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Nucleic acids in plant tissue lysates can be captured quickly by a cellulose filter paper and prepared for amplification after a quick purification. In this study, a published filter paper strip method was modified by sticking the filter paper on a polyvinyl chloride resin (PVC) sheet. This modified method is named EZ-D, for EASY DNA extraction. Compared with the original cetyl trimethylammonium bromide (CTAB) method, DNA extracted by EZ-D is more efficient in polymerase chain reaction (PCR) amplification due to the more stable performance of the EZ-D stick. The EZ-D method is also faster, easier, and cheaper. PCR analyses showed that DNA extracted from several types of plant tissues by EZ-D was appropriate for specific identification of biological samples. A regular PCR reaction can detect the EZ-D-extracted DNA template at concentration as low as 0.1 ng/μL. Evaluation of the EZ-D showed that DNA extracts could be successfully amplified by PCR reaction for DNA fragments up to 3000 bp in length and up to 80% in GC content. EZ-D was successfully used for DNA extraction from a variety of plant species and plant tissues. Moreover, when EZ-D was combined with the loop-mediated isothermal amplification (LAMP) method, DNA identification of biological samples could be achieved without the need for specialized equipment. As an optimized DNA purification method, EZ-D shows great advantages in application and can be used widely in laboratories where equipment is limited and rapid results are required.

In this study, a new solid phase extraction method based on the use of a low-cost funnel-shaped partially carbonized cellulose filter paper as a sorbent has been developed. The sorbent is easily prepared by heating the folded filter paper wetted with sulfuric acid solution and can be reused for several times. It is combined with dispersive liquid–liquid microextraction and used for the extraction of some pesticide residues from fruit juice samples prior to their analysis by gas chromatography–flame ionization detection. In this work, limits of detection and quantification were in the ranges of 0.30–0.61 and 1.0–2.0 µg L−1, respectively, and relative standard deviations ranged between 3 and 6% for intra– (n=5) and inter–day (n=5) precisions at a concentration of 25 µg L−1 of each pesticide. The enrichment factors of 452–751 were achieved. Extraction recoveries were in the range of 45–75%. The calibration curves had wide linear ranges with a good linearity (coefficient of determination ≥ 0.994). Finally, efficiency of the method was apprised by determining the analytes in fruit juice samples and relative recoveries were found to be in the range of 85–101%.

In newborn screening, samples suspected for congenital adrenal hyperplasia (CAH), a potentially lethal inborn error of steroid biosynthesis, need to be confirmed using liquid chromatography–tandem mass spectrometry. Daily quality controls (QCs) for the 2nd-tier CAH assay are not commercially available and are therefore generally prepared within the laboratory. For the first time, we aimed to compare five different QC preparation approaches used in routine diagnostics for CAH on the concentrations of cortisol, 21-deoxycortisol, 11-deoxycortisol, 4-androstenedione and 17-hydroxyprogesterone in dried blood spots. The techniques from Prep1 to Prep5 were tested at two analyte concentrations by spiking aliquots of a steroid-depleted blood, derived from washed erythrocyte suspension and steroid-depleted serum. The preparation processes differed in the sequence of the preparation steps and whether freeze-thaw cycles were used to facilitate blood homogeneity. The five types of dried blood spot QCs were assayed and quantitated in duplicate on five different days using a single calibration row per day. Inter-assay variations less than 15% and concentrations within ±15% of the nominal values were considered acceptable. Results obtained by means of the four dried blood spot QC preparation techniques (Prep1, Prep2, Prep4 and Prep5) were statistically similar and remained within the ±15% ranges in terms of both reproducibility and nominal values. However, concentration results for Prep3 (spiking prior to three freeze-thaw cycles) were significantly lower than the nominal values in this setting, with differences exceeding the ±15% range in many cases despite acceptable inter-assay variations. These findings have implications for the in-house preparation of QC samples in laboratory developed tests for CAH, including 2nd-tier assays in newborn screening.

Workplace-collected blood spots deposited on filter paper were analysed with multiplexed affinity-based protein assays and found to be suitable for proteomics analysis. The protein extension assay (PEA) was used to characterize 92 proteins using 1.2 mm punches in repeated samples collected from 20 workers. Overall, 97.8% of the samples and 91.3% of the analysed proteins passed quality control. Both within and between spot correlations using six replicates from the same individual were above 0.99, suggesting that comparable levels are obtained from multiple punches from the same spot and from consecutive spots. Protein levels from dried blood and wet serum from the same individuals were compared and the majority of the analysed proteins were found to be significantly correlated. These results open up for simplified sample collection of blood in field conditions for proteomic analysis, but also highlight that not all proteins can be robustly measured from dried whole blood.

In this study, a paper-based sensor, combined with a visual distance-readout method, was developed to determine glucose in fruit samples based on the glucose oxidase-mediated sodium alginate gelation. The type of filter paper, the concentration of sodium alginate and the enzymatic reaction conditions were systematically investigated. Under optimal conditions, the increase in diffusion diameter showed a good linear relationship with glucose concentration between 1.4–7.0 mM, and the limit of quantification was 1.4 mM. Finally, the applicability of the proposed strategy was successfully verified by measuring glucose concentrations in fruit samples. The results generated by the developed paper-based sensor were in good agreement with the results obtained from a glucose assay kit. The recoveries were 91.8%–99.1%. In short, the present study developed a simple, low-cost and efficient method for assessing fruit quality and for guiding fruit intake for diabetic patients, especially in remote or resource-limited regions.

While current trends in Green Analytical Chemistry aim at reducing or simplifying sample treatment, food usually comprises complex matrices where direct analysis is not possible in most cases. In this context, sample treatment plays a pivotal role. Biogenic amines are naturally formed in many foodstuffs due to the action of microorganisms, while their presence has been associated with adverse health effects. In this work, the extraction of seven biogenic amines (cadaverine, histamine, phenylethylamine, putrescine, spermidine, spermine, and tyramine) from beer samples has been simplified using laboratory filter paper as sorbent without any further modification. The analysis of the eluates by direct infusion mass spectrometry reduces the time of analysis, increasing the sample throughput. This simple but effective method enabled the determination of the analytes with limits of detection as low as 0.06 mg•L−1 and relative standard deviations better than 11.9 %. The suitability of the method has been assessed by analyzing eight different types of beers by the standard addition method.

Objectives Fabry disease (FD) is an X-linked lysosomal storage disorder, resulting from a deficiency of the enzyme α-galactosidase A, responsible for breaking down glycolipids such as globotriaosylceramide and its deacylated derivative, globotriaosylsphingosine (LysoGb3). Here, we compare the levels of LysoGb3 in dried blood spots (DBS) and plasma in patients with classic and late-onset phenotypes. Methods LysoGb3 measurements were performed in 104 FD patients, 39 males and 65 females. Venous blood was collected. A portion was spotted onto filter paper and another portion separated to obtain plasma. The LysoGb3 concentrations in DBS and plasma were determined by highly sensitive electrospray ionization liquid chromatography tandem mass spectrometry. Agreement between different matrices was assessed using linear regression and Bland Altman analysis. Results The method on DBS was validated by evaluating its precision, accuracy, matrix effect, recovery, and stability. The analytical performances were verified by comparison of a total of 104 paired DBS and plasma samples from as many FD patients (representing 46 GLA variants). There was a strong correlation between plasma and the corresponding DBS LysoGb3 concentrations, with few exceptions. Discrepancies were observed in anemic patients with typically low hematocrit levels compared to the normal range. Conclusions The method proved to be efficient for the rapid analysis of LysoGb3. DBS provides a convenient, sensitive, and reproducible method for measuring LysoGb3 levels for diagnosis, initial phenotypic assignment, and therapeutic monitoring in patients with FD.

The aim of this study was to validate a workflow that allows structural identification of plant volatiles that induce a behavioral response in insects. Due to the complexity of plant volatile emissions and the low levels at which these bioactive components tend to occur, gas chromatography-electroantennography (GC-EAD) was applied as the prime differentiator technique, i.e., to indicate particular peaks of interest in the chromatogram. In a next step, the analysis was repeated under identical conditions using GC-Orbitrap mass spectrometry (MS). Combining electron impact (EI) ionization and chemical ionization (CI) with the superior spectral resolution and mass accuracy of the technique enabled straightforward identification of these unknowns, with high confidence in a minute amount of time. Moreover, because of the intrinsic sensitivity of the technique, components that occur at trace amounts but may induce disproportional large behavioral responses are evenly well-identified. We were able to positively identify β-caryophyllene as a bioactive compound in female carob moths. Behavioral attraction was negatively correlated with the amount of β-caryophyllene in host fruits. In an oviposition experiment on filter paper, β-caryophyllene was stimulated in the range of 40–100 ng, while concentrations above 200 ng inhibited oviposition.

Anurans (frogs and toads) expelled urine when handled and it could provide insights into their physiological status. However, storage, preservation and transportation are often challenging. The study aimed to standardize and validate a field method for short-term storage and preserve of anuran urine samples using Whatman filter papers. To examine the efficacy of storage conditions and type of papers, urinary based enzyme immunoassays were used to measure progesterone and testosterone hormone metabolites. High-Performance Liquid Chromatography was performed and revealed immunoreactive progesterone and testosterone metabolites in the urine samples. Urinary hormone metabolites concentration stored in filter paper at room temperature and control samples stored in -20°C for the same period were similar. Whatman grade 50 was found to be more suitable for storage of hormones than grade 3 paper for the experiments performed.•A cheap and simple storage method for storage of anuran urine in field conditions using filter papers.•Anuran urine could be preserved and transported under ambient conditions without significant changes and loss of hormones.•This method would facilitate the endocrine monitoring of anurans in remote areas where limited logistics are available., Graphical abstract Image, graphical abstract

A synthetic microbial consortium called Effective Microorganisms (EM) consists mainly of photosynthetic bacteria, lactic acid bacteria and yeast. Various effects of EM∙XGOLD, a health drink produced by EM, on life cycle of Dictyostelium discoideum were described previously. Here, we report our attempt to identify the active principle, termed EMF, that brought about the observed effects. Throughout the purification processes, the presence of the active principle was monitored by promoted fruiting body formation. By liquid-liquid separation the activity was recovered in aqueous phase, which, after concentration, was further subjected to reverse-phase column chromatography. No activity was detected in any eluant, while almost all the activity was recovered in residual insoluble material. The application of conventional organic chemistry procedures to the residual fraction did not lead to any informative results. Acid treatment of the insoluble material produced air bubbles, suggesting it to be composed of some inorganic carbonate. Viewed under scanning electronmicroscope, the residue revealed spherical particles of μm size range. Energy Dispersive X-ray (EDX) Spectroscopy pointed to the existence, on the surface of the particles, of magnesium and, to a certain extent, of potassium. In separate experiments, acid treatment and alkali neutralization of EM∙XGOLD completely wiped out the stimulatory activity of fruiting body formation. These lines of evidence indicate these Mg, K-containing microparticles to be an active principle of EM culture extract. How these particles exert their effect is currently under intensive investigation.

Made available in DSpace on 2019-10-06T17:04:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-06-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Development and application of a new, simple, inexpensive, and eco-friendly method is presented for the quantification of bumetanide in human urine samples for the detection of doping in sports. The method involves the use of a paper platform and digital image detection and is based on the reaction between bumetanide, p-dimethylaminocinnamaldehyde (p-DAC), and HCl in a methanolic medium, yielding a colored compound in a delimited area on a qualitative filter paper. The concentrations of p-DAC and HCl were optimized by a chemometric experimental design. After the addition of the reagents to the paper, digital images were obtained by scanning in a multifunctional printer and analyzed using the RGB pattern. The linear bumetanide concentration range was 6.90 × 10 −5 –1.37 × 10 −3 mol L −1 with R 2 = 0.993 and the limits of detection (LOD) and quantification (LOQ) were 3.60 × 10 −4 and 1.09 × 10 −4 mol L −1 , respectively. A SPE clean-up step for the samples were required to eliminate the interference of urinary urea. The recoveries obtained varied from 94% to 105%, indicating the absence of significant matrix effects or interferences in urine samples after clean-up step. The proposed method was successfully applied to the analysis of bumetanide in human urine samples. Instituto de Química Universidade Estadual Paulista “Júlio de Mesquita Filho” UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 Instituto de Química Universidade Estadual Paulista “Júlio de Mesquita Filho” UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 CAPES: 001 FAPESP: 2015/21733-1

This study demonstrates the feasibility of successive digestions as a strategy for Br and I pre-concentration and ultra-trace determination by ion chromatography and plasma-based spectrometric techniques. Digestion and pre-concentration steps were performed by using microwave-induced combustion (MIC), and milk powder samples for adult and infant nutrition were used as an example of application. Samples were pressed as pellets (up to 0.7 g) and combusted in closed quartz vessels pressurized with oxygen. Up to 5 combustion cycles were sequentially performed using the same vessel without changing the absorbing solution. In each cycle, a new filter paper, igniter, and sample pellet (0.7 g) were used allowing digestion and pre-concentration. Ammonium hydroxide solutions (100 to 300 mmol L−1) were evaluated for analytes absorption. Using 300 mmol L−1 NH4OH as absorbing solution, up to 5 digestion cycles (0.7 g each cycle, total mass of 3.5 g) can be applied while keeping a suitable relative standard deviation (

In the last years, the imprinting technology has raised attention and different polymers with artificial recognition sites towards a target molecule have been developed. In this article, a polymerization-free method ―which only requires the dissolution of nylon-6 polymer and its subsequent incubation with the template molecule― has been employed for the preparation of a molecularly imprinted polymer directly immobilized on filter paper, thus increasing the versatility and manageability of the new material. The molecularly imprinted paper-based analytical device (MIP PAD) has been coupled to a fluorimeter via a custom-built platform, which enables direct measurement of the fluorescence at the surface of the MIP PAD. Extraction efficiency of the MIP PAD was evaluated using quinine as model analyte, measuring the fluorescence directly at the MIP PAD surface after incubation on aqueous standards of quinine and soda drink, showing that the performance of the imprinted material was superior to that of the non-imprinted polymer. In addition, the selectivity of the MIP PAD versus analogous organic fluorescent molecules has been further evaluated using norfloxacin, observing that the molecular imprinting results in selective extraction of quinine. The performance of the method has been evaluated for quantitative analysis, achieving limits of detection (LOD) and quantification (LOQ) for aqueous standards of 0.37 and 1.24 mg L−1, respectively, while in the case of spiked soda drink the LOD and LOQ were 0.63 and 2.11 mg L−1, respectively. The reproducibility of the measurements was also evaluated, observing values within range 2.30 and 9.07% measured as relative standard deviation.

Introduction. The actual form of packaging licorice roots for water extraction are filter paper sachets. New forms of licorice root processing provide the proper technological properties of raw materials for filter paper sachets.Aim. A comparative assessment of the of glycyrrhizic acid (GA) content in licorice roots (LR), produced in the Russian Federation and in licorice raw materials of various processing methods by HPLC-UV.Materials and methods. The objects of research were crushed LR, packaged in packs of industrial production and laboratory-industrial samples of coarse powder (CP), cut-pressed granules (CPG) and compositions proposed for packaging in filter paper sachets. The determination of GA content was carried out on an Agilent 1200 high performance liquid chromatography system equipped with a photodiode array detector (Agilent Technologies, USA). The stationary phase is column Phenomenex Luna® C18 (2) 250×4.6 mm. The composition of the mobile phase – 5% orthophosphoric acid water solution: acetonitrile (60:40). A flow rate – 1.0 ml/min, isocratic elution mode. The temperature of the column – 30 °C. The sample injected volume – 10 µl. Detection was performed at a wavelength of 254 nm; run time – 15 minutes.Results and discussion. The GA content in CP, CPG and the composition of CP and CPG –was determined in the ratio of 80:20 (composition). It was established that the GA content varies in the LR in the range – 7.08–9.17%, CP – 3.87–3.90%, CPG – 6.88–7.08%, and the composition – 4.44–4.88%.Conclusion. The use of HPLC-UV method for the standardization of licorice roots of domestic production and the roots of various forms of processing is very promising. The technique can be recommended for inclusion in the State Pharmacopoeia of the Russian Federation of a subsequent edition, which will allow harmonizing the quality requirements of domestic licorice raw materials with the requirements of foreign pharmacopoeias.

The present work describes the development and validation of a novel approach to determine methadone (MTD) and its main metabolite (EDDP) in oral fluid samples, using the dried saliva spots (DSS) sampling approach and gas chromatography-tandem mass spectrometry (GC-MS/MS). Oral fluid samples (50 μL) were applied into Whatman™ 903 protein saver filter paper cards and were allowed to dry overnight. The extraction was carried out by immersion of the spot in 1 mL of isopropyl alcohol with agitation for 1 min. Afterwards, the extract was centrifuged for 15 min at 3500 rpm and the supernatant evaporated to dryness and reconstituted with 50 μL of methanol. The procedure was considered linear in the range of 10 to 250 ng/mL for both compounds, with determination coefficients greater than 0.99. Intra- and inter-day precision and accuracy revealed coefficients of variation (CVs) lower than 15% at the studied concentrations, with mean relative errors within ± 15% of the nominal concentrations. Recoveries ranged from 45 to 74%. The limits of detection and quantification were 5 and 10 ng/mL respectively for both analytes. All studied parameters complied with the defined criteria and the method enabled the successful determination of MTD and EDDP in oral fluid samples from patients undergoing opiate substitution/maintenance therapy.

The aim of this study was to test the use of IP-10 detection in dried plasma from contact studies individuals (contacts of smear positive patients), by comparing it with IP-10 and IFN-γ detection in direct plasma, to establish IP-10 detection in DPS as a useful assay for LTBI diagnosis. Whole blood samples were collected from 80 subjects: 12 with active tuberculosis (TB), and 68 from contact studies. The amount of IFN-γ produced by sensitized T cells was determined in direct plasma by QuantiFERON Gold In-Tube test. IP-10 levels were determined in direct and dried plasma by an in-house ELISA. For dried plasma IP-10 determination, two 25 µl plasma drops were dried in Whatman903 filter paper and sent by mail to the laboratory. Regarding TB patients, 100.0%, 91.7% and 75.0% were positive for IFN-γ detection and IP-10 detection in direct and dried plasma, respectively. In contacts, 69.1%, 60.3% and 48.5% had positive results after IFN-γ and IP-10 in direct and dried plasma, respectively. The agreement among in vitro tests was substantial and IP-10 levels in direct and dried plasma were strongly correlated (r = 0.897). In conclusion, IP-10 detection in dried plasma is a simple and safe method that would help improve LTBI management.

In this study, levels of inflammatory protein biomarkers in venous plasma, plasma derived from capillary blood from the earlobe, and capillary plasma stored as dried plasma spots (DPS) were compared. Samples from 12 male individuals were assessed with a panel of 92 inflammation-related proteins using multiplex proximity extension assay. Correlations between sample types varied greatly between analytes. A high correlation of rho > 0.8 was observed between capillary plasma and DPS for 32 analytes. At this level of correlation, 13 analytes correlated between venous and capillary plasma and 5 analytes in the comparison of venous blood with DPS.

Background Measuring concentrations of metabolites of estradiol and progesterone in urine, instead of measuring serum concentrations, is common in research and also is used in patient care. The primary aim of this study was to demonstrate that analysis of urine samples dried on filter paper by gas chromatography with tandem mass spectrometry (GC–MS/MS) provides results similar to serum analyzed by radioimmunoassay (RIA). Secondary aims were to show that collection of four samples during the day (4-spot method) can be substituted for a 24-h collection, and that analysis of urine from dried samples is equivalent to liquid urine samples. Methods This prospective observational study compared results of urine and serum analyses. Urine samples from women throughout the menstrual cycle and single samples from postmenopausal women were evaluated. Urine was collected onto filter paper and dried. Dried urine was extracted, hydrolyzed, and derivatized prior to analysis by GC–MS/MS. Hormone concentrations were normalized to creatinine. Single samples were used to compare results of 24-h urine collection to the 4-spot method from a separate population of women and men. A subset of these samples were used to compare results from dried urine to liquid urine. Results The primary study showed good reliability in the comparisons between the dried urine and serum assays. During the menstrual cycles of a subset of four women, urine metabolite concentrations followed the same pattern as serum concentrations. Comparison of 4-spot to 24-h urine collections and of dried to liquid urine measurements had intraclass correlation coefficients (ICC) greater than 0.95, indicating excellent agreement. Conclusions For estradiol and progesterone, the dried urine assay is a good surrogate for serum testing. The 4-spot method can be used instead of 24-h urine collections and dried urine results are comparable to liquid urine. The dried urine assay is useful for some clinical assessments of hormone disorders and may be useful in large epidemiologic studies due to ease of sample handling. Electronic supplementary material The online version of this article (10.1186/s13065-019-0539-1) contains supplementary material, which is available to authorized users.

This work demonstrates a sensitive and rapid method for the detection of antibiotic residues in food samples by employing the filtration behaviour of paper combined with aggregation and precipitation of chemical reagents. Using this concept, we successfully determined the presence of oxytetracycline and norfloxacin residues in pork using metal complexation on microfluidic paper-based analytical devices (μPADs). The base substrate (top layer of the device) was fabricated by printing letter channels of the words “oxytetracycline” and “norfloxacin” before functionalization with copper (II) sulfate pentahydrate in 0.5 M sodium hydroxide and iron (III) nitrate nanohydrate in 5 mM ammonia solution for the detection of oxytetracycline and norfloxacin separately. A transition metal hydroxide formed upon reaction that created solid precipitates on paper and allowed antibiotic residues to bind to the metal ions via coordination chemistry. The metal ion-antibiotic complex could form on the filter paper and generated a visible color change with the detection limit of 1 ppm for both oxytetracycline and norfloxacin in pork. This procedure of filtration and concentration in combination with a simple text-reporting approach allows the end users to achieve a low limit of detection as well as easy result interpretation in food safety monitoring. usc Refereed/Peer-reviewed

To address the issues allied with cardiovascular diseases and the increased prevalence of hypertension, a novel electrochemical sensor was developed based on poly(ionic liquid) [PVIM]-cobalt polyoxometalate (Co5POM) supported on carbonaceous materials (MNCs) for the highly selective and ultrasensitive non-enzymatic detection of cholesterol. The novel composite exhibits excellent selectivity and sensitivity towards the non-enzymatic electrochemical detection of cholesterol with a low detection limit of 1 fM (1 × 10-15 M), a response time of ∼5 s, and a wide detection range of 1 fM-5 mM with two linear ranges of 1 fM-200 nM and 0.5 μM-5 mM with sensitivities of 210 and 64 μA μM-1 cm-2, respectively, even in the presence of ascorbic acid, glucose and uric acid. The proposed sensor was tested with a human blood serum sample at physiological pH in a physiologically relevant concentration range. A novel flexible sensor was developed with PVIM-Co5POM/MNC coated over Whatman filter paper and this shows a high sensitivity with a wide detection range of 1 fM-5 mM.

This comparative study proposes an efficient technique by employing a synthetic substrate, which is commercially available, for direct, sensitive, efficient and fast analysis in Paper Spray Mass Spectrometry (PS-MS). The Teslin® substrate is a well-known synthetic paper used in the printing industry, and it is made with a single-layered, microporous polyolefin–silica matrix. Currently, filter paper is one of the most commonly used natural cellulose fiber-based substrates in PS-MS. In this study, the analytical performance of Teslin® vs. filter paper was determined by measuring different physical characteristics such as porosity, solvent elution efficiency and sensitivity of both substrates. The key result of electrostatic-spray ionization in the hydrophobic Teslin® substrate was more efficient detection and direct analysis of a smaller amount of drug samples (1 μL) with an improved signal sensitivity of 26.94-fold in comparison to filter paper. It has been demonstrated that the efficiency of reproducibility of the analyte, signal-noise ratio, and constant longer active signal (>2 min) were notably improved with the hydrophobicity of Teslin® paper by eliminating chromatographic effects. The limit of detection for drug analysis was reported to be in the lower μg mL−1 range.

Herein, a new colorimetric paper sensor based on the layer-by-layer assembled multilayers of a cationic surfactant, tetrabutylammonium bromide (TBABr), and an anionic surfactant, sodium dodecyl sulfate (SDS), modified on filter paper was developed for the determination of total antioxidant capacity (TAC). In this study, gallic acid (GA) was used as the antioxidant standard. The fabricated (TBABr/SDS)3/PAD was loaded with Fe3+ ions to obtain Fe3+/(TBABr/SDS)3/PAD, exhibiting high selectivity for the detection of GA when compared with the case of other metal ions. The interaction between GA and the Fe3+/(TBABr/SDS)3/PAD sensor occurred rapidly, and the colorimetric paper sensor changed from yellow to purple immediately. The quantitative detection of GA was enabled by taking an image using an ordinary smartphone and applying the ImageJ software based on the change in color. Under optimum conditions, a linear response was obtained between the change in the color of the sensor and the TAC value expressed in terms of gallic acid equivalents. The linear range was from 0.50 μM to 6.50 mM with the detection limit of 0.35 μM. The colorimetric paper sensor was applied to detect the TAC in three kinds of green tea and vegetable samples, which provided the good recoveries of 86.0–109.9%. The proposed sensor is simple, cheap, equipment-free, rapid and environmentally friendly. In addition, the colorimetric sensor Fe3+/(TBABr/SDS)3/PAD has potential applicability for TAC detection in real food samples.

Glyphosate is widely used herbicides and causes several diseases in humans. Therefore, the detection of glyphosate is curial and urgent. Studies on the detection of glyphosate in literature are often based on inhibition of the enzyme acetylcholinesterase. In this study, we developed two simple colorimetric sensors, BP-Cl and CP-Cl, by linking 3-chloro-4-methylpyridine with 4-(dimethylamino)cinnamaldehyde or 4-(dimethylamino)benzaldehyde in a one-step reaction. The colorimetric and optical sensing properties of these compounds were investigated by the naked-eye and UV-Vis spectrophotometer in ACN/HEPES buffer (5 mM pH 8.0, 1:1 v/v). The sensors displayed high sensitivity and selectivity for glyphosate by color changes, which ranged from colorless to yellow for BP-Cl and yellow to orange for CP-Cl. The detection limits of BP-Cl and CP-Cl by the naked-eye detection were found as 15 mM and 10 mM. On the other hand, the detection limits of BP-Cl and CP-Cl via UV-Vis measurements were calculated as 0.847 mM and 1.23 mM, respectively. Moreover, the sensors were able to monitor glyphosate in water samples using the naked-eye, UV-Vis spectroscopy, and filter paper strips. (c) 2021 Elsevier B.V. All rights reserved.

Developing rapid and reliable method for simultaneous hormones quantitation is of great significant because of important roles of hormones in metabolism. However, current methods are faced with problems of low throughput or complicated operation procedure to remove matrices from serum samples in routine clinical diagnosis. In the present work, a multilayer PS-MS method was developed for rapid and simple detection of hormones. In the strategy, multilayer filter paper acted as the Liquid Chromatography in LC-MS/MS for separation of hormones and biological matrices. Qualitative and quantitative analysis of three hormones, testosterone (T), androsterone (ADT) and androstenedione (4-AD) were realized through MS/MS spectra. The method exhibited linearity in the range of 0.02–2 μg/L and the results of recovery and repeatability were satisfactory for standard samples and spiked serum. The time-cost of a whole detection process was less than 3 min. The established multilayer PS-MS realized rapid, simple and reliable quantitative analysis of various hormones and provided broad prospect for clinical analysis of small molecules in different biological samples. Moreover, it provides a novel MS approach with high through-put and free HPLC, meeting the requirements of point-of-care testing (POCT).

Cellulose nanocrystals (CNCs) have gained increased interest worldwide for their unique properties. CNC production by acid hydrolysis of cellulose-rich biomass is well established, but its' quantification is still complicated. In this study, a rapid method for the determination of CNC concentration using Calcofluor White (CW) fluorescence dye is demonstrated for both purified and homemade CNCs recovered from Whatman filter paper. The method is robust, selective for crystalline cellulose, suitable for routine measurement in CNC production and that the pH must be basic for staining using CW.

The objective of this work was to compare the quality, purity and quantity of DNA isolated from dried blood spots (DBS) by three methods (Chelex-100, QIAamp DNA mini kit, and TE (Tris EDTA)-Buffer). Sample collection was performed in six districts in Odisha, India and screened for cases of clinical malaria and dengue and vector density. Mosquito abdomens were spotted on Whatman 3MM (MERCK) Filter paper and dried for 10 min at room temperature. DNA was isolated from DBS using three methods (Chelex-100, QIAamp DNA mini kit, and TE-Buffer), and PCR was used to determine the feeding behaviours of vector mosquitoes. DNA was quantified using a UV-spectrophotometer, and q-PCR was used to determine the target gene copy number to compare the methods. The QIAamp DNA mini kit method was used as the reference method. The yield and purity of DNA extracted with Chelex-100 and TE were 14–72 ng/µl and 1.51–1.85 and 9–50 ng/µl and 1.68–2.1, respectively. DNA extracted using the Chelex-100 method was stored for over 1 month at − 20 °C and was suitable for later use. The Chelex-100 method had a sensitivity of 99.5% and specificity of 78%. A Bland–Altman plot suggested that the Chelex-100 method was similar to the QIAamp DNA mini kit method for determining the feeding behaviours of vector mosquitoes. The Chelex-100 method is simple, cost-effective, and safe and requires minimal time for DNA extraction from dried blood spots. In malaria and dengue research, detecting the feeding behaviours from mosquito DNA from dried blood spots on filter paper by PCR is an easy, minimally invasive and inexpensive molecular technique that can be performed in remote areas.

A microfluidic paper-based analytical device (μ-PAD) and handheld colorimeter android application for quantifying the precise concentration of adulterants in milk are developed. A simple method to pattern polydimethylsiloxane for creating a hydrophobic barrier on filter paper using custom-designed rubber stamp containing the design of μ-PAD was used. The experiments were performed for the detection of urea, starch, salt and detergent ranging from 1 to 100 mg in 10 ml of milk. The user just needs to pipette drops of adulterated milk on a test spot and the results are obtained instantly. The authors believe that the developed platform can be used as a basis for low-cost, portable system for various fluid adulterants’ tests. The experimental database was used for the development of a colorimetric android application to calibrate the colour range for adulterants’ concentration detection. The limit of detection of colorimetric android application for adulterants urea is 5 mg, starch is 17 mg, salt is 29 mg and for detergent is 20 mg in 10 ml of milk. This kind of system is attractive for use in developing countries, in the field, or as an inexpensive alternative as compared with other methods for water and food safety.

Background Protein-containing samples can readily be characterised and/or identified using matrix-assisted laser-desorption and ionisation time-of-flight mass spectrometry (MALDI-TOF MS). This technique however requires relatively-fresh biological material that contains proteins that have not yet undergone significant degradation. For field-work collection of samples, problems are often encountered due to delays between collection and sample processing, sample storage (possibly at elevated temperature and/or humidity in some climates), quarantine/regulatory restrictions on the transfer of living biological materials across national borders, and the potential to transfer unwanted microorganisms via non-living biological materials. Results In an attempt to overcome the above difficulties, we have developed a simple and inexpensive method for practical storage of field-sample proteins, for subsequent MALDI-TOF MS analysis, in which biological material is crushed onto filter paper and dried. The dried and protein-impregnated filter paper can then be soaked in an alcoholic solution suitable for the inactivation of microorganisms of concern and again dried for storage. After subsequent dry storage, the proteins may be eluted from the paper using a solution containing acetonitrile, trifluoroacetic acid, water, and MALDI-TOF MS matrix near to saturation. The extracted proteins are then pipetted onto the MALDI-TOF MS sample plate for subsequent analysis. Using this method, spectra of comparable quality to fresh-material controls have been obtained for acid-soluble proteins from Fallopia japonica and Impatiens glandulifera leaf material. Unlike untreated leaf material, high-quality spectra can be obtained with and without alcohol treatment even after storage for one month at up to 40 °C. Conclusions We have developed a simple and inexpensive method for practical storage of field-sample proteins for subsequent MALDI-TOF MS analysis. Key benefits of this approach are a reduction in sample degradation, and consequent conservation of taxon-discriminatory spectral profiles, whilst minimising the potential for carryover of viable microorganisms. Electronic supplementary material The online version of this article (10.1186/s13007-018-0358-8) contains supplementary material, which is available to authorized users.

In this work we report a novel paper-based analytical device read-out via LED-induced fluorescence detection (FPAD) for the quantification of the emerging pollutant ethinylestradiol (EE2) in river water samples. The PAD was used as a reaction platform for a competitive enzyme immunoassay. For the PAD development, microzones of filter paper, printed by a wax printing method, were modified with amino-functionalized SBA-15 and subsequently, anti-EE2 specific antibodies were covalently immobilized. The determination of EE2 in water was carried out by adding a fixed concentration of EE2 conjugated with the enzyme horseradish peroxidase (HRP) to samples and standards. Then, the FPAD were added and incubated for 10 min. Finally, the detection was performed by the reaction of 10-acetyl-3,7-dihydroxyphenoxazine (ADHP) whose oxidation is catalyzed by HRP in the presence of H2O2, obtaining the highly fluorescent resorufin (R). Resorufin was detected by LED excitation at 550 nm, observing emission at 585 nm. The EE2 concentration in the samples was inversely proportional to the relative fluorescence obtained from the enzymatic reaction products. The FPAD assay showed a detection limit (LOD) of 0.05 ng L−1 and coefficients of variation (CV) below 4.5% within-assay and below 6.5% between-assay, respectively. The results obtained show the potential suitability of our FPAD for the selective and sensitive quantification of EE2 in river water samples. In addition, it has the PADs advantages of being disposable, easy to apply and inexpensive. Fil: Scala Benuzzi, María Luz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina Fil: Takara, Eduardo Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina Fil: Alderete, Mara. Universidad Nacional de San Martin. Instituto de Nanosistemas; Argentina Fil: Soler Illia, Galo Juan de Avila Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martin. Instituto de Nanosistemas; Argentina Fil: Schneider, Rudolf J.. Bundesanstalt für Materialforschung und -prüfung; Alemania Fil: Raba, Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina Fil: Messina, Germán Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina

In the present study, we have developed a smartphone based handheld optical biosensor for determination of urea in saliva. A simple strategy was adopted by immobilization of urease enzyme along with a pH indicator on a filter paper based strip. The strip changed color upon the reaction with urea present in saliva and the color change can be estimated using our smartphone based application based on RGB profiling. Calibration of the biosensor was carried out using spiked saliva samples and an exponentially decreasing calibration curve has been obtained for green pixel intensity in the broad range (10–1000 mgdL−1) with a linear detection range of 10–260 mgdL−1 and a response time of 20 s. The sensitivity reported for the biosensor in the clinically significant range was −0.005 average pixels sec−1/mgdL−1 with a LOD of 10.4 mgdL−1. Studies carried out on spiked saliva samples showed a good correlation between salivary urea estimated using our biosensor against phenol-hypochlorite based spectroscopic procedure. Development of a smartphone based biosensor for urea estimation eliminates the need for procuring a dedicated instrument as well as trained technician for daily monitoring and saves time as compared to traditional laboratory methods of analysis.

Mosquito has comprehensive and sensitive olfactory neuro-sensory located at antenna utilized for detecting airborne organic compounds in search of blood host. Mosquito is also known to have similar neurotransmitters function with human at neural synapses e.g. acetylcholinesterase, esterases and oxidases enzymes. Thus, there is potential use mosquito in predicting neurotoxicity of exogenic volatile organic compounds (VOC) e.g. manufactured acetone. Hence, the study evaluates the suitability to conduct bioassay of VOC neurotoxicity against mosquito in Peet Grady chamber that is commonly used for insecticidal bioassay. Acetone as the representative of VOC is easily evaporized at laboratory temperature of 26 to 29 °C without heating. The acetone evaporation profile on liquid surface and porous solid surface under the Peet Grady chamber is studied to ascertain the consistency of vaporization rate with homogenized distribution. The study showed the acetone has shown consistent vaporization rate of 23 mg/min from liquid surface and 116.3 mg/min from porous surface (filter paper) without heating, in a linear regression of very high positive correlation (r = 1.000) between time and mass of acetone vaporized. However, the non-homogenized distribution of acetone vapours in the Peet Grady chamber directly affected the accuracy to elucidate the neurotoxicity bioassay against mosquito in term of mosquito knockdown. The study suggests the positioning of mosquitoes in the Peet Grady chamber should be lower than the point of acetone vaporization, whereby the mosquitoes are knockdown by acetone vapours within the 20th minute upon reaching concentration of 170.3 to 196.1 ppm.

A novel approach for serum analysis by dried matrix spot (DMS) technique is proposed. The methodology consists of sampling filter paper discs (2.7 mm in diameter) containing the large amount of serum retained after a single spotting. Several oxidizers (sodium chlorate, sodium azide, acetic acid, formic acid, 1-butyl-3-methylimidazoliumm chloride/bromide) were tested (oxidizers premixed with the sample before spotting, and papers previously soaked in concentrated additive/oxidizer solutions). Direct multi-element determination (Al, Be, Ca, Cu, Fe, K, Li, Mg, Mn, Mo, Na, P, Rb, Se, V, and Zn) in dried serum spots at very low levels was therefore assessed by laser ablation (LA) coupled with inductively coupled plasma - mass spectrometry (ICP-MS). Laser ablation was performed using a focused Nd: YAG laser beam in lineal scan mode (wavelength 213 nm, laser fluency 2.2 J cm−2, repetition rate 20 Hz, laser spot diameter 90 µm, depth 0 µm, scanning speed 12 µm s−1). Matrix-matched calibration mode and 13C as internal standard (for signal intensities normalization) was used throughout the work. Limits of quantification were found to be from 21 µg L−1 to 221 mg L−1. Repeatability (seven ablations of the same dried serum spot) and reproducibility (two ablations of seven dried serum spot from the same material) offered RSDs below 12% for all analytes, which seems satisfactory for clinical purposes. The method was validated by analyzing several certified reference materials (Seronorm™ level I and II trace elements in serum), and it was applied to several DMS from serum samples from healthy adults.

Atypical myopathy (AM) in horses is caused by ingestion of seeds or seedlings of some maple trees (Acer species, sapindaceae family). Elevated concentrations of acyl conjugates, a sign of inhibited s-oxidation of fatty acids, are diagnostic for AM. Quantification of acyl conjugates is currently not part of the standard test scheme of veterinary laboratories but is done routinely in laboratories screening human newborns for inborn errors of metabolism. It was our aim to show that the screening method, which is based on the use of whole blood dried on filter paper, can be applied to samples from horses with the single methodological adaptation, that is, spotting serum instead of whole blood on the filter paper. Acylcarnitines (ACs) were measured by tandem mass spectrometry after butylation. Results were compared with those obtained by ultraperformance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) in the corresponding liquid samples. Inhibition of fatty acid s-oxidation was unequivocally shown by elevated concentrations of butyryl-/isobutyrylcarnitine, valeryl-/isovalerylcarnitine, and hexanoylcarnitine (intraday coefficient of variation

Highlights • Retrieval of BoHV-1 DNA from extended semen spotted paper matrix was optimized. • The method was repeatable in inter-assay and intra-assay precision testing. • Viral DNA was stable in the matrix for at least 28 days when stored at 4°–37 °C. • The analytical sensitivity was equivalent to the OIE approved Chelex based method. • The dsn and dsp was 83% and 93% respectively in comparison to Chelex based method., The extended frozen semen (EFS) batches produced from infectious bovine rhinotracheitis (IBR) sero-positive cattle and buffalo bulls housed in various semen stations in India are transported to the testing laboratory in liquid nitrogen (LN2) for screening bovine herpesvirus-1 (BoHV-1). This procedure is laborious and poses LN2 related hazards. An alternative logistics for transportation of samples was investigated. Use of Flinders Technology Associates (FTA®) elute card was evaluated for transportation of extended bovine semen to screen BoHV-1 DNA by real-time PCR targeting gB gene and the method was compared with the OIE approved Chelex resin based method. A protocol for extraction of BoHV-1 DNA from FTA® card spotted with extended semen was optimized. The viral DNA was found to be stable on FTA® card for at least 28 days when the cards are stored at 4°–37 °C. The analytical sensitivity for the assay was determined using variable dilutions of BoHV-1 spiked semen and positive plasmid harbouring gB gene (97bp) spotted onto FTA® card and it was found to be 100.8 TCID50/ml or 100 copies respectively in real-time PCR. The test could detect as low as 100.008 TCID50/ml or 1 copy of positive plasmid when more number of replicates (n = 6) of the same sample were tested. This sensitivity was found to be comparable to Chelex method and both the methods demonstrated a very strong correlation (r = 0.9774; 95% CI: 0.9620–0.9860) in terms of Ct value (p

In the present study, electrospun polyethylene terephthalate nanofibers doped with graphene oxide nanoparticles (GO-PET) was fabricated and used as an effective adsorbent in micro-solid phase extraction (μ-SPE) of tetracycline (TC) and cefotaxime (CF) from honey samples prior to HPLC. The UV–vis spectrophotometer was utilized in the optimization step. The adsorbent was fully characterized using SEM, FT-IR, BET, and BJH methods. The specific surface area and average pore size of the adsorbent were 79.5 m2 g−1 and 4.83 nm, respectively. The honey samples were dissolved in water (5% w/v) at 50 °C for 10 min, centrifuged at 4000 rpm for 15 min and finally filtered using a filter paper before performing the extraction. The important factors of the method were studied to obtain the optimal conditions. Under the optimum conditions (sample solution, 100 mL; adsorbent, 40 mg; pH 5; extraction time, 10 min; desorption solvent; MeOH, 200 μL), the limits of detection for TC and CF were 15.3 and 3.0 μg kg−1. The linear dynamic range (LDR) was obtained as 10–5000 μg kg−1 with the determination coefficients (R2) of 0.9939 and 0.9959, respectively. The real sample extraction recoveries were 89–94% and 95–98% for TC and CF, respectively. The intra-day and inter-day precisions were 5.6 and 4.9% (n = 3) for TC, and 3.6 and 4.5% (n = 9) for CF.

We introduce a novel centrifugal disc for purifying nucleic acid (NA) in a high-throughput manner to perform the human sex-typing of forensic samples. The centrifugal disc was designed with double-sided etched channels to fabricate 30 extraction units, which was capable of purifying 30 forensic samples in a single run. In order to introduce the washing solution (70% ethanol) and the elution buffer for the 30 extraction units in an automatic manner, we designed the aliquoting chambers that were connected with a zigzag delivery channel. The super-hydrophobic zigzag-shaped aliquot structure plays a crucial role in automatically dividing the washing solution and the elution buffer into 30 aliquots with one injection shot. The Whatman glass filter paper was used as an NA extraction matrix and sophisticated passive valves were equipped to avoid the overflowing of these buffers to the neighboring chamber during the injection. To operate the disc, we developed a portable workstation that consists of a buffer storage system, a buffer injection system, and a spinning unit. The entire process was automatically operated by the in-house portable workstation. Genomic DNA extraction using thirty forensic samples was completed in 10 min. Using the purified genomic DNA, we performed a loop-mediated isothermal amplification (LAMP) reaction for sex-typing by targeting the human alphoid repeat sequence of the Y-chromosome and the human 18S rRNA. The combination of the high-throughput centrifugal disc for NA extraction and the LAMP reaction enables us to complete the genetic sex-typing in 30 min.

Hexavalent chromium is a toxic heavy metal getting discharged into the environment and water bodies through various industrial processes. Conventional analysis methods call for expensive equipment and complicated sample pretreatment that made unsuitable for onsite detection. Paper is used as an enzyme immobilization platform because of its property to wick the liquid by capillary action; lightweight, cheap and can be easily patterned or cut according to the requirements for developing biosensor. In this study, enzyme immobilization of glucose oxidase (GOx) on filter paper were examined using three polysaccharides such as chitosan, sodium alginate and dextran for entrapment efficiency, activity and stability of the immobilized enzyme. Among the three, chitosan proved efficient for enzyme entrapment with about 90% efficiency at 0.3% (w/v) chitosan. The stability was checked after 1 week at 4 °C and room temperature, where the chitosan entrapped enzyme retained nearly 97% stability at 4 °C. Enzyme inhibition study of GOx and Cr(VI) was carried out using chronoamperometry shown uncompetitive type of inhibition. A paper-based electrochemical biosensor strip was developed by immobilizing GOx enzyme on filter paper using chitosan as an entrapping agent and associating it with a screen-printed carbon electrode for amperometric measurements. The linear range of detection was obtained as 0.05–1 ppm with the limit of detection as 0.05 ppm for Cr(VI), which is the standard permissible limit in potable water. The relative standard deviation (5.6%) indicates good reproducibility of the fabricated biosensor.

Background Mass spectrometry allows for analysis of multiple hormone and organic acid metabolites from small urine volumes; however, to assess the full extent of daily hormone production, 24-h urine collections are usually required. The aims of this study were, first, to confirm that mass spectrometric analysis of an array of hormones and organic acids would yield similar results in both liquid and dried urine, and, second, to determine if collection of four dried spot urine samples could be substituted for a 24-h collection when measuring reproductive hormones. Methods Two study populations were included in this prospective observational study. Twenty individuals collected both a spot liquid urine and dried urine on filter paper to analyze eight organic acids. A second group of 26 individuals collected both a 24-h urine and four dried spot urines during waking hours throughout the same day for evaluation of 17 reproductive hormones and metabolites; data from 18 of these individuals were available to compare liquid versus dried urine results. Dried urine was extracted, hydrolyzed, and derivatized before analysis by mass spectrometry; all analytes from dried urine were normalized to urine creatinine. Results Reproductive hormone results from dried and liquid urine were in excellent agreement with intraclass correlation coefficients (ICCs) greater than 0.90; comparison of dried to liquid urine for organic acids showed good to excellent agreement (ICC range: 0.75 to 0.99). Comparison between the 4-spot urine collection and 24-h urine collection methods showed excellent agreement (ICC > 0.9) for 14 of the 17 urine metabolites and good agreement for the others (ICC 0.78 to 0.85) with no systematic differences between the two methods of collection. Conclusions The burden of urine collection can be reduced using collection of four spot dried urines on filter paper without compromising comparability with hormone results from a 24-h urine collection. A large number of urine analytes can be assessed from the dried urine with similar results to those from liquid urine. Given the ease of sample handling, this 4-spot dried urine assay would be useful for both clinical assessment of patients and for large epidemiologic studies.

In this work, cellulose filter paper (CFP), which is inexpensive and commercially available, was used as the carrier, and the immobilized α-glucosidase was obtained by two steps: firstly, the surface of CFP was modified by polydopamine/polyethyleneimine (PDA/PEI) co-deposition method to obtain CFP-PDA/PEI with a uniform coating of rich positive charge; subsequently, α-glucosidase was immobilized on the CFP-PDA/PEI by electrostatic adsorption. The free enzyme and immobilized enzyme have the same optimal temperature (70℃) and pH (8.0), and their Km is similar, which is 2.2 and 2.8, respectively. These results show that the immobilization process does not change the properties of the enzyme greatly. The immobilized enzyme still maintains 75.6% of its initial activity after 10 repeated uses, showing good reusability. The excellent repeatability (RSD = 2.2%, n = 5) and the verification of competitive inhibitor (acarbose) illustrates the reliability of the immobilized enzymes for enzyme inhibitor screening. Finally, combined with CE, a screening method based immobilized α-glucosidase was proposed and applied to screen the α-glucosidase inhibitory from 10 kinds of Traditional Chinese medicines (TCMs) in vitro. The results indicated that the method was a very effective tool for screening potential α-glucosidase inhibitors from TCMs.

A novel, low-cost, and portable paper strip biosensor was developed for the detection of tetracycline antibiotics. Escherichia coli/pMTLacZ containing the tetracycline-mediated regulatory gene used as recognition elements with β-galactosidase as the reporter protein was designed and applied to cheap and portable Whatman filter paper as the carrier to prepare this paper strip biosensor. The detection process was optimized by using EDTA and polymyxin B as a sensitizer to improve the accuracy of detection for complicated matrices. The paper strip biosensor was suitable for tetracycline concentrations in the range of 75–10000 μg/L in water and 75–7500 μg/L in soil extracts. Detection limits of 5.23–17.1 μg/L for water and 5.21–35.3 μg/kg for the EDTA soil extracts were achieved at a response time of 90 min. The standard deviation (SD) of detected values by the biosensor paper strip compared to those determined by HPLC was between 13.4 and 59.6% for tetracycline and 2.01–33.5% for oxytetracycline in water and was between 6.22 and 72.8% for tetracycline and 5.90–43.4% for oxytetracycline in soil. This suggests that the paper strip biosensor was suitable for detecting both tetracycline and oxytetracycline in water, and could provide a suitable detection for extractable oxytetracycline in soils. Therefore, this biosensor provides a simple, economical, and portable piece of field kit for on-site monitoring of tetracyclines in a variety of environmental samples, such as pond water and agricultural soil that are susceptible to tetracycline pollution from feed additives and fertilization with livestock manure.

BACKGROUND Drug concentrations of antiepileptic drugs (AEDs) are routinely determined from blood serum or plasma at trough levels (before intake of morning dose). In capillary blood collection, blood is taken from the fingertip with the aid of a disposable tool and dried on absorbent material. The volumetric absorptive microsampling technique offers several advantages over the use of filter paper cards. The aim of this study was to determine conversion factors for the estimation of AED serum concentrations from capillary blood concentrations. METHODS Venous and capillary blood samples were collected from adult inpatients with epilepsy who were treated with lacosamide (LCM, n = 30), lamotrigine (LTG, n = 40), and/or levetiracetam (LEV, n = 36). A validated liquid chromatography-mass spectrometry (LC-MS) method for dried blood samples for these AEDs was compared with routine serum laboratory methods. Method agreement was evaluated using different regression techniques, and the conversion factors were calculated. RESULTS Regression analyses revealed a linear relationship between serum and capillary blood concentrations for all 3 AEDs (r ≥ 0.95). For LTG, the regression intercept was significantly different from 0, indicating that the relationship was linear, but not necessarily proportional. Although LEV and LCM concentrations tended to be lower in capillary blood than in serum (mean ratio of serum concentration to capillary blood concentration: 1.14 and 1.22, respectively), LTG concentrations were higher in capillary blood (mean ratio = 0.85). CONCLUSIONS The estimation of serum concentrations from measured capillary blood concentrations is feasible for LCM, LTG, and LEV. A simple ratio approach using the mean ratio and Passing-Bablok regression showed the best results for all 3 AEDs. The volumetric absorptive microsampling technique facilitates the quantitative sample collection of capillary blood and overcomes the drawbacks associated with the classical dried blood spot technique.

Alcohol intoxication is usually associated with drowning, falls, overdoses, fires, occupational accidents, physical and sexual abusements, domestic violence and traffic accidents. Therefore, alcohol considered an important factor for the explanation of the occurrence of many types of injuries. For many purposes such as forensic, it is important to establish a detection method to ensure whether the subject or the patient have consumed alcohol at a level that would be the reason for the accidents or injuries occur. Therefore, in this work, a simple, rapid and low-cost method was developed and validated for the detection of the alcohol in saliva as a function of blood alcohol concentration (BAC). The method is based on fabricated a biosensor consisted of chromium oxide nanoparticles deposited on filter paper. The validation of the biosensor was tested on 50 participants which categories into two selected groups (1 and 2). Group 1 consisted of 20 subjects from an organized party (no alcohol), they usually consumed three to four drinks as an average per week while Group 2 consisted of 30 subjects from an organized party the local bar (alcohol group), usually consumed two to three drinks per day. The results of the present study have shown that 95% of group 1 demonstrated positive results with variable colour intensities of the BAC in comparison to the 80% only of subjects from group 2. The present study has approved that the fabricated biosensor can effectively detect 0.02% or more of BAC which can be a useful test for many purposes such as medical, forensic, research and workplace.

Introduction: Alternative methods of dry storage and transportation may be a viable alternative to the use of liquid storage medium for cervical samples, especially for screening programs in places with few resources. Objective: The objective of this study is to verify the viability and efficacy of human papillomavirus DNA (HPV-DNA) detection in cervical cell samples collected and stored on a Flinders Technology Associates (FTA) card (Whatman Indicating FTA® Elute Micro Card) and subsequently recovered in ethanol-based liquid medium and to compare the results to those obtained using samples stored directly in ethanol-based liquid medium. Study Design: Thirty-four women submitted to ETZ (excision of the transformation zone of the cervix) were included in this study. Before ETZ, 2 samples of exfoliated cervical cells were collected from each woman by a doctor and stored in ethanol-based liquid medium and on an FTA card. DNA recovery from FTA samples was performed using ethanol-based liquid medium. Detection of HPV-DNA in the samples was performed using the Cobas® 4800 HPV Test Platform. Results and Conclusions: The HPV-DNA detection positivity rates were 70.6% for the samples collected directly in liquid medium and 64.7% for the samples stored on the FTA card, with high detection accuracy in the DNA samples recovered from the FTA card (area under the curve = 0.958; 95% confidence interval = 0.890–1.000). The concordance between the results obtained using the 2 storage media was 94.1% (Kappa = 0.866). These preliminary results suggest that collection of cervical material on an FTA card may be an alternative to storage in liquid medium since the liquid medium has some limitations. In addition, DNA recovery from the card using ethanol-based liquid medium streamlines the workflow in the laboratory and reduces the cost associated with reagents, thereby facilitating access to the HPV test in places with few resources and potentially improving cervical cancer screening.

This study introduces an applicable colorimetric sensor array for the detection of pesticides in the vapor phase. The array consisted of six metal nanoparticles spotted on the piece of filter paper. 3D-origami pattern was used for the fabrication of a paper-based sensor to decrease the effect of the nanoparticles leaching after exposure to analytes. Exposure to pesticide aerosols caused changes in the color of the array due to the aggregation of nanoparticles. These changes provided selective responses to thion pesticides such as malathion, parathion, chlorpyrifos, and diazinon. The sensing assay could also differentiate between aliphatic and aromatic thions and discriminate amine-containing compounds from the other studied analytes. These finding results are clearly confirmed by both visual detection and multivariate statistical methods. The proposed sensor was successfully developed for the quantitative measurement of pesticide aerosols at a very low concentration. The limit of detection of this method determined for malathion, parathion, chlorpyrifos and diazinon were 58.0, 103.0, 81.0 and 117.0, respectively. Moreover, the array could be employed to simultaneously analyze four studied pesticides. The statistcal results confirmed that the method has high performance for concurrent detection of thions as a major air pollutant without the interference of other species.

Quantitative analysis of amino acids in blood and urine is primarily indicated for the diagnosis of amino acid disorders. The high-performance liquid chromatography (HPLC) technique is frequently used for this detection. The frequency of sample collection on filter paper has been increasing exponentially, and there are many advantages attributed to processing biological samples in this way. The aim of this study was to validate a quantitative analysis of amino acids by HPLC in blood and urine collected on filter paper and to establish reference values in the neonatal period. Dried blood and dried urine samples of respectively 58 and 45 healthy newborns (2-9 days) were collected. Pre-treatment and extraction of samples were done according to the literature. Separation and analysis of amino acids were carried out by HPLC with fluorescence detection. The developed method demonstrated excellent separation, linearity, limits of detection and quantification, repeatability and recovery. The reference values for 17 amino acids were defined in dried blood and urine samples of newborns. This work presents a simple, fast and effective method for the simultaneous analysis of 17 amino acids in blood and urine collected on filter paper in a single run. The reference values were established and validated.

Paper-based polymeric ionic liquid (p-Poly-(MMA-IL)) was successfully developed by grafting the polymeric ionic liquid on the surface of commercial filter paper by using dipping method, presenting a new cost-effective film. The newly developed p-Poly-(MMA-IL) was then applied as a paper-based thin film microextraction (p-TFME) to extract four representative sulfonamides (SAs) drugs, which were sulfadiazine, sulfachloropyridazine, sulfamethoxazole, and sulfadimethoxine in environmental water samples. Besides, p-Poly-(MMA-IL) was successfully characterised by FTIR, FESEM, and XRD techniques and underwent significant parameters optimisation, which affected the extraction efficiency. Under optimal conditions, the proposed method (p-Poly-(MMA-IL)-TFME) was evaluated and applied to analyse SAs in environmental water samples by using a high-performance liquid chromatography-diode array detector (HPLC-DAD). The validation method showed that a good linearity (0.50 µg L-1 –500 µg L-1) was noted (R2 > 0.999, n = 3). Detection and quantification limits were within 0.14 µg L-1 – 0.52 µg L-1 and 0.41 – 1.57 µg L-1, respectively, the preconcentraction factors were > 14.95, and the matrix effect was less than 2.64%, an acceptable percentage for real samples analysis. The extraction recoveries of environmental water samples were ranged from 90.4% to 109.9% with a relative standard deviation (RSD) of less than 9.8%. The newly developed paper-based polymeric ionic liquid (p-Poly-(MMA-IL) for analysis of SAs under the p-TFME procedure was successfully achieved with limited sample volume and organic solvent, fast extraction, and practicable in the daily analysis.

Ferritin, a blood cell protein containing iron, is a crucial biomarker that is used to estimate the risk assessment of iron deficiency anemia. For point-of-care analysis, a reliable, cost-effective, selective, sensitive, and portable tool is extremely necessary. In this study, a label-free electrochemical immunosensor for detecting ferritin using a paper-based analytical device (ePAD) was created. The device pattern was custom designed onto filter paper to successfully fabricate a deliverable immunosensor. Graphene oxide was first modified onto the working electrode using an inkjet printing technique. An activation step of the electrode surface was then performed using standard 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC)/N-hydroxysulfosuccinimide (sulfo-NHS) chemistry. Anti-ferritin antibodies were covalently immobilized onto the amine-reactive ester surface. The amount of ferritin was monitored by observing the electrochemical signal of the selected redox couple by differential pulse voltammetry (DPV). In the presence of ferritin, the sensor showed a considerable decrease in electrochemical response in a concentration-dependent manner. In contrast, there was no observable change in current response detected in the absence of ferritin. The current response provided a good correlation with ferritin concentrations in the range of 1 to 1000 ng mL-1, and the limit of detection (3SD/slope) was found to be 0.19 ng mL-1. This fabricated immunosensor offered good selectivity, reproducibility, and long-term storage stability. In addition, this proposed immunosensor was successfully applied to detect ferritin in human serum with satisfactory results. The promising results suggested that this handmade paper-based immunosensor may be an alternative device for the diagnosis of iron deficiency anemia.

Ultrasensitive detection of specific biomarkers in clinical serum is helpful for early diagnosis of cervical cancer. In this paper, a surface-enhanced Raman scattering (SERS)-based immunoassay was developed for the simultaneous determination of squamous cell carcinoma antigen (SCCA) and osteopontin (OPN) in cervical cancer serum. Au-Ag nanoshuttles (Au-AgNSs) as SERS tags and hydrophobic filter paper-based Au nanoflowers (AuNFs) as capture substrate were constructed into a sandwich structure which served as an ultrasensitive SERS-based immunoassay platform. Finite difference time domain simulation confirmed that the electromagnetic field coupled between the AuNFs had a prominent SERS signal enhancement effect, which improved the detection sensitivity. SERS mapping showed that hexadecenyl succinic anhydride hydrophobic treatment could prevent the analyte from being quickly absorbed by the filter paper and increase the retention time to be more evenly distributed on the filter paper substrate. The immunoassay platform was verified to have good selectivity and reproducibility. With this method, the detection limits of SCCA and OPN in human serum were as low as 8.628 pg/mL and 4.388 pg/mL, respectively. Finally, in order to verify the feasibility of its clinical application, the serum samples of healthy subjects; cervical intraepithelial neoplasia I (CINI), CINII, and CINIII; and cervical cancer patients were analyzed, and the reliability of the results was confirmed by enzyme-linked immunosorbent assay experiments. The constructed SERS-based immunoassay platform could be used as a clinical tool for early screening of cancers in the future.

Purpose In this study, an aqueous two-phase micellar system (ATPMS), formed by the non-ionic surfactant Triton X-114, was used to investigate the partitioning of cellulolytic enzymes produced by the filamentous fungus Aspergillus fumigatus CCT 7873. Methods Performance of the ATPMS on the partitioning of CMCase (activity on carboxymethyl cellulose) and FPase (activity on filter paper) was investigated by varying the temperature (35, 40, 45, 50, 55, 60, and 65 °C), enzyme crude extract concentration (20, 40, 60, and 80% w/w), and Triton X-114 concentration (2, 4, 6, and 8% w/w) and by adding different inorganic salts (NaCl, CaCl2, MgSO4, and MnSO4) in the system. Results An ATPMS formed with 8% (w/w) Triton X-114 and 40% (w/w) enzymatic crude extract at a system temperature of 55 °C was most favorable for partitioning the tested enzymes. Under these conditions, a purification factor for CMCase and FPase of 10.89 and 0.65 was reached, respectively. The addition of inorganic salts changed the distribution of enzymes. Of these, CaCl2 contributed to a higher distribution coefficient (50.0), whereas for FPase, the presence of MnSO4 in the system improved the purification factor to 3.94. Conclusion The highest values obtained for the yield and purification factors demonstrate that ATPMS is an interesting option for recovering and purifying cellulolytic enzymes.