Search

The conventional tissue biopsy method yields isolated snapshots of a narrow region. Therefore, it cannot facilitate comprehensive disease characterization and monitoring. Recently, the detection of tumor-derived components in body fluids─a practice known as liquid biopsy─has attracted increased attention from the biochemical research and clinical application viewpoints. In this vein, surface-enhanced Raman scattering (SERS) has been identified as one of the most powerful liquid-biopsy analysis techniques, owing to its high sensitivity and specificity. Moreover, it affords high-capacity spectral multiplexing for simultaneous target detection and a unique ability to obtain intrinsic biomolecule-fingerprint spectra. This paper presents the fabrication of silver nanosnowflakes (SNSFs) using the polyol method and their subsequent dropping onto a hydrophobic filter paper. The SERS substrate, which comprises the SNSFs and hydrophobic filter paper, facilitates the simultaneous detection of creatinine and cortisol in human sweat using a hand-held Raman spectrometer. The proposed SERS system affords Raman spectrometry to be performed on small sample volumes (2 μL) to identify the normal and at-risk creatinine and cortisol groups.

In this study, it was aimed to develop a simple, accurate, and sensitive analytical strategy for the determination of nitrite in processed meat products using a solid optical chemosensor and digital imaging system. The method is simply based on formation of azo dyes obtained by mixing the powdered 1-naphthy lamine, N, N-dimethyl aniline, and nitrite solution under acidic conditions and the colorimetric analysis of the color formed on glass microfiber filter paper by a digital-based imaging system. All the system parameters in color formation and detection steps were optimized to lower the detection limit. In the optimal experimental conditions, detection limit, percent relative standard deviation, and R2 values were determined as 0.64 mg/L, 0.64%, and 0.994, respectively. Recovery results (99.2–121.6%) were calculated for different sausage and salami samples spiked at two different concentrations. Unlike the standard azo dyestuff–based methods, the method is environmentally friendly, fast, simple, and cheap since organic solvents are not used during the analysis.

A novel paper-based analytical device (PAD) was prepared and applied to determine the xanthine oxidase (XOD) inhibitory activity of Salvia miltiorrhiza extracts. First, polycaprolactone was 3D printed on filter paper and heated to form hydrophobic barriers. Then the modified paper was cut according to the specific design. Necessary reagents including XOD for the colorimetric assay were immobilized on two separate pieces of paper. By simply adding phosphate buffer, the reaction was performed on the double-layer PADs. Quantitative results were obtained by analyzing the color intensity with the specialized device system (including a smartphone, a detection box and sandwich plates). The 3D-printed detection box was small, with a size of 9.0 cm × 7.0 cm × 11.5 cm. Color component G performs well in terms of linearity and detection limits and thus was identified as the index. The reaction conditions were optimized using a definitive screening design. Moreover, a 10 % glycerol solution was found to be a suitable stabilizer. When the stabilizer was added, the activity of XOD could be maintained for at least 15 days under 4 °C or -20 °C storage conditions. The inhibitory activity of Salvia miltiorrhiza extracts was investigated and compared to that of allopurinol. The results obtained with the PADs showed agreement with those obtained with the microplate method. In conclusion, the proposed PAD method is simple, accurate and has potential for point-of-care testing. It also holds promise for use in rapid quality testing of medicinal herbs, intermediate products, and preparations of traditional Chinese medicines.

Extracellular vesicles (EVs) play a significant role in the pathophysiological process of many diseases, highlighting their values in medical diagnosis and disease monitoring. However, the current EV isolation methods are time-consuming, inconvenient to operate, and incompatible with downstream analyses. Here, we present a novel isolation method employing anionic polysaccharide-modified filter papers for the isolation of EVs (AppiEV) via electrostatic adsorption. A disc of glass fiber-based filter modified with sodium alginate was assembled into a spin column to function as the solid capture phase. In the acidic condition, EVs were induced to carry more positively charged ions, which enable the capture of EVs by the negatively charged filter paper. After a wash, the EVs were released from the spin column using an alkaline elution buffer, which induces the EVs to carry more negative charges. The EVs isolated by AppiEV from cell culture supernatants, plasma, and urine are similar to or even better than those isolated by ultracentrifugation in terms of EV size distribution, protein distribution, and nucleic acid contents. Due to the interference removal of the EV-free RNA and DNA attributed to the negatively charged capture medium, the eluate of AppiEV could be directly used for genetic analysis, including the stem-loop RT-PCR analysis of miR-21 and the allele-specific PCR analysis of mutation genes of EGFR p.L858R and EGFR p.T790M. We believe that AppiEV offers a simple and efficient approach for the isolation of high-quality EVs from various liquid specimens.

We have evolved a completely unique, reliable HPLC technique for simultaneous quantification of Fostemsavir and Ganciclovir. The chromatographic detachment was attained on an X-Bridge phenyl column (150x4.6mm, 3.5 µ) using isocratic elution with a buffer containing 0.1% OPA and acetonitrile proportion of 50:50 as movable part with a stream of 1 mL/min at room temperature. The maximum absorbance of the drugs was observed at 236 nm. Dissolve 1mL of orthophosphoric acid in 1 lt of HPLC marked water and sieved by using 0.45 µ filter paper, this solution was used as a buffer. 10 min run time was used to separate Fostemsavir and Ganciclovir. Analysis was achieved within 15 min over honest linearity within the concentration range from 6-90 µg/mL of Fostemsavir and 2.5-37.5 µg/mL of Ganciclovir. To check the system suitability parameters, the normal solution was injected six times, from the outcomes, it was concluded that all the outcomes were well under the acceptable range. Precision and recovery study results were well under a suitable range. From this technique, an assay of Fostemsavir and Ganciclovir was performed and the results were well under the acceptable range. Degradation studies were carried out on Fostemsavir and Ganciclovir, with a purity threshold greater than the purity angle in all conditions and within the acceptable range. The above-mentioned technique was validated according to ICH guidelines.

In this research, simultaneous quantification of cysteine (Cys) and histidine (His) using a paper-based sensor was investigated for the first time. A microfluidic paper-based sensor is a promising amino acid determination tool due to its low cost, low sample consumption, and fast analysis and is easy to make. We used SBA-15 as porous materials that are crystalline compounds formed with surfactants and TEOS as a silica source. The SBA-15 sample was characterized by X-ray diffraction, Fourier transform infrared, and scanning electron microscope techniques. The microfluidic paper-based sensors were fabricated using a wax pen, and the mesoporous SBA-15 modified filter paper. The fabricated sensors for Cys and His determination are operated based on an indicator-displacement assay. A comparative determination study of Cys and His on the sensors was carried out. The results illustrated that the addition of silica nanoporous material led to an immediate and uniform color change. The sensors were successfully exploited in the simultaneous determination of urinary Cys and His levels, thus providing the potential opportunity for clinical diagnosis. The linear range of 1.0 to 90.0 μM and 1.0 to 100 μM for His and Cys was obtained from the calibration data. The detection limits were also calculated (S/N = 3) for His and Cys of 0.5 μM and 1.5 μM, respectively. The proposed method showed a good agreement with the results achieved by a standard method.

Phosphatidylethanol (PEth) is a group of phospholipids formed in cell membranes following alcohol consumption by action of the enzyme phospholipase D (PLD). PEth measurement in whole blood samples is established as a specific alcohol biomarker with clinical and forensic applications. However, in blood specimens containing ethanol, formation of PEth may continue after sampling leading to falsely elevated concentrations. This study evaluated the use of dried blood spot (DBS) and microsampling specimens to avoid post-sampling formation of PEth. Filter paper cards and three commercial devices for volumetric microsampling of finger-pricked blood were assessed, using PEth-negative and PEth-positive whole blood fortified with 2 g/L ethanol. PEth (16:0/18:1) was measured by LC–MS/MS. Post-sampling formation of PEth occurred in wet blood and in the volumetric devices, but not filter paper cards, when stored at room temperature for 48 h. Addition of an inhibitor of PLD, sodium metavanadate (NaVO3), eliminated post-sampling formation during storage and drying. In conclusion, the present study confirmed previous observations that PEth can be formed in blood samples after collection, if the specimen contains ethanol. The results further demonstrated that post-sampling formation of PEth from ethanol also occurred with commercial devices for volumetric dried blood microsampling. In order for a PEth result not to be questioned, it is recommended to use a PLD inhibitor, whether venous blood is collected in a vacutainer tube or finger-pricked blood is obtained using devices for dried blood microsampling. Graphical abstract

We have developed a completely unique and reliable HPLC technique for simultaneous quantification of Lopinavir and Rilpivirine. Chromatographic detachment was attained on a X-bridge phenyl column (150x4.6mm, 3.5 µ) using isocratic elution with a buffer containing buffer and acetonitrile with the proportion of 70:30 as movable phase with a flow of 1 ml/min at room temperature and UV detection was carried out at 250 nm. Dissolve 1ml of tri ethylamine in 1 lt of HPLC grade water and filter through 0.45 µ filter paper, this solution was used as buffer. 8 min. run time was used to separate Lopinavir and Rilpivirine. Analysis was achieved within 15 min over an honest linearity within the concentration range from 20-300 µg/ml of Lopinavir and 2.5-37.5 µg/ml of Rilpivirine. By injecting the standard six times, system suitability parameters were studied and the outcomes were under the acceptable limit. Precision and recovery study results were found to be within the suitable limit. By using the above technique, assay of Lopinavir and Rilpivirine was performed and found to be within the limit. Degradation studies were carried out on Lopinavir and Rilpivirine, with a purity threshold greater than purity angle in all conditions and within the allowable range. The above mentioned technique was validated according to ICH guidelines.

We have developed a completely unique and reliable HPLC technique for simultaneous quantification of Cisplatin and Topotecan. A chromatographic detachment was attained on a XDB C18 column (150x4.6mm, 3.5 µ) using isocratic elution with a buffer containing buffer and acetonitrile with the proportion of 60:40 as a movable phase with a flow of 1 mL/min at room temperature and UV detection was carried out at 262 nm. Dissolve 1mL of triethylamine in 1 lt of HPLC grade water and filter through 0.45 µ filter paper. This solution was used as a buffer. 10 min run time was used to separate Cisplatin and Topotecan. The analysis was achieved within 15 min over honest linearity within the concentration range from 5-75 µg/mL of Cisplatin and 2-30 µg/mL of Topotecan. By injecting the standard six times, system suitability parameters were studied and the outcomes were under the acceptable limit. Precision and recovery study results were found to be within a suitable limit. By using the above technique, the assay of the marketed formulation was performed and found to be within the limit. Degradation studies were carried out on Cisplatin and Topotecan, with a purity threshold greater than the purity angle in all conditions and within the acceptable range. The above-mentioned technique was validated according to ICH guidelines.

Portable fluorescent test strips with off-line visual detection have become a hit in the field of target analysis. Yet, common fluorescent test strips are mainly based on filter papers, which usually suffer from poor visual detection effect owing to the “coffee ring effect”. Herein, an ingenious ratio fluorescent test strip was successfully prepared based on the polyvinylidene fluoride (PVDF) hydrophobic membrane for rapid, selective and off-line visual detection of 4-nitrophenol (4-NP). Interestingly, two surprising discoveries were made: one was, strategically used, the green-emission fluorescence polydopamine (F-PDA) function as both fluorescence functional monomer and response signal during the synthesis of ratiometric fluorescent probe (CdTe@SiO2@F-PDA/MIPs), which greatly shortened the detection time of 4-NP. Another was, the PVDF membrane with hydrophobicity and colorless fluorescent background effectively overcame the “coffee ring effect” and fluorescence background interference. Compared with other hydrophobic membranes, the PVDF hydrophobic membrane was rough enough to load more CdTe@SiO2@F-PDA/MIPs, which provided more recognition sites for 4-NP detection. Finally, the PVDF fluorescent test strip exhibited a much lower detection limit of 2.77 nM within 1.5 min (90 s). The visual detection comparison experiment showed that the color changes of the PVDF fluorescent test strip to 4-NP were lightly identifiable and more obvious than that with a traditional filter paper. Moreover, the detection reliability of CdTe@SiO2@F-PDA/MIPs was verified by the comparison experiment of high-performance liquid chromatography (HPLC), and satisfactory results were ultimately obtained.

The present work describes a sensitive, simple, cost-effective and fast analytical procedure to detect the parabens in industrial waste effluent water samples using novel activated carbon nanofiber (CNF) modified filter paper based solid phase extraction technique coupled with liquid chromatography with photodiode array detector (UPLC-PDA). The carbon nanofiber coated filter paper was used as an adsorbent and also characterized by field emission scanning electron microscope (FESEM) showed superior porous structure. Various factors effecting the adsorption and desorption process were studied. The optimum parameters which improve the efficiency are paper length 1 cm × 2 cm, adsorption time 15 min, eluent methanol, eluent volume 5 mL, sample pH 7, desorption time 2 min, 2% salt addition and 300 rpm stirring rate respectively. The parabens exhibited superior linearity ranging from 0.1-50 ng mL-1. The regression coefficient (R2) value ranging from 0.9981-0.9989. This method exhibited good sensitivity with the quantification limit (LOQ) between 0.5-0.75 ng mL-1 and detection limit (LOD) over the range of 0.1-0.25 ng mL-1. The precision was expressed from the RSDs values from 0.74-0.97 %. The spiked analytes revealed excellent recoveries in the range of 95.30-116.72 % with RSD less than 5.72 % for all the water samples also applied for real samples.

In this study, we developed a novel, simple, rapid, and low-cost colloidal gold-based immunochromatography method, with filter paper replacing nitrocellulose membrane as the substrate. To obtain adequately immobilized protein, chitosan was used to functionalize the filter paper. After conditions and parameters were optimized, the novel immunochromatography method was applied for detection of sulfonamide residues in milk. Quantitative detection was accomplished using a smartphone and Photoshop software (Adobe Inc., San Jose, CA), allowing us to screen 13 sulfonamides with a limit of detection ranging from 0.42 to 8.64 μg/L and recovery ranging from 88.2 to 116.9% in milk. The proposed novel method performed similarly to the conventional method that uses a nitrocellulose membrane as the transport medium, and it had lower cost and better usability because of the inexpensive and easily available filter paper.

La elevada incidencia del Enterococcus faecalis en procedimientos odontológicos es un tópico de interés para el área de la salud, esta bacteria resiste a varios antimicrobianos y su proliferación aumenta debido a su baja susceptibilidad a sustancias de uso convencional como el hidróxido de calcio, convirtiéndose en una de las principales causas del fracaso de los tratamientos de conducto. La presente investigación evaluó la susceptibilidad in vitro del Enterococcus faecalis cepa ATCC-29212 frente a la combinación de sustancias y antibióticos con el hidróxido de calcio. Se utilizó la técnica de difusión en agar, inoculando el microorganismo en cajas de Petri con agar Cerebro Corazón (BHI), tratado con discos de papel filtro impregnados con 1µl de cada tratamiento por triplicado; T1 (Hidróxido de Calcio + propilenglicol), T2 (Hidróxido de Calcio + paramonoclorofenol), T3 (Hidróxido de Calcio + ampicilina gentamicina + propilenglicol), T4 (Hidróxido de Calcio + Solución Salina Fisiológica), Control positivo (medicamento comercial a base de Hidróxido de Calcio), se incubó a 35°C durante 24h, los halos formados alrededor de cada disco fueron medidos y comparados con la escala de Duraffourd y procesados mediante ANOVA de un factor. Se obtuvo una medida del halo de inhibición de 22,50±3,3 mm, con el tratamiento T3, siendo sumamente sensible. Concluyendo que este resultó el más efectivo en comparación el resto de las pruebas in vitro en comparación con el resto de los fármacos investigados.

This study was conducted on crude enzyme from the novel strain Acanthophysium sp. KMF001 using a mediator (surfactant). The surfactant was applied to the steam-exploded pretreated domestic wood biomass, and response surface methodology (RSM) was conducted to determine the optimum conditions for saccharification using the optimum substrate concentration, enzyme concentration, and surfactant concentration. Steam-explosion of Korean oak (25 kgf/cm2) for 7 min showed a maximum-predicted saccharification of approximately 99.9% at 7.0% substrate concentration, 37.5 FPU (filter paper units) enzyme concentration, and 475.8 mg/g-glucan surfactant (polysorbate 80) concentration. Steam-explosion of red pine (25 kgf/cm2) for 7 min revealed a maximum prediction saccharification rate of approximately 58.7% at 6.5% substrate concentration, 36.3 FPU enzyme concentration, and 330.3 mg/g-glucan surfactant (polysorbate 80) concentration. The extents of saccharification of Korean oak (99.9%) and pine (58.7%) demonstrated the high applicability of the crude enzyme from Acanthophysium sp. KMF001.

Phosphatidylethanol (PEth), which is formed by enzymatic reaction between ethanol and phosphatidylcholine, is a direct marker for alcohol usage. PEth has a long elimination half-life (~5-10 d) and specimens can be sampled using minimally invasive microsampling strategies. In combination with rapid analysis procedures PEth has proved to be advantageous for the detection of abstinence over other direct (e.g., ethyl glucuronide in blood, urine or hair) and indirect (e.g., carbohydrate-deficient transferrin in serum) alcohol markers. Although PEth determination is widely applied around the world, laboratory protocols are not standardized. Here we provide general guidelines for the analysis of PEth in dried blood spots (DBSs), including reference material evaluation, synthesis of a deuterated internal standard, preparation of calibration samples (reference material in teetotaller blood), and analyte separation and detection. The protocol contains information to extract the DBSs either manually or with a fully automated autosampler. Extraction of the analytes from DBS filter paper cards is performed using an organic extraction, followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). For accurate and reliable measurement of PEth, the two most abundant analogs, PEth 16:0/18:1 and PEth 16:0/18:2, are quantified. We show data that provide guidelines on how to interpret the results for both demographic studies and forensic applications. The described protocol can be applied by experienced laboratory staff with basic LC-MS/MS knowledge and takes 2 d to perform.

Conventional mass spectrometry (MS)-based analytical methods for small carbohydrate fragments (oligosaccharides, degree of polymerization 2–12) are time-consuming due to the need for offline sample pretreatment such as desalting. Herein, we report a new paper spray ionization method, named desalting paper spray (DPS), which employs a piece of triangular filter paper for both sample desalting and ionization. Unlike regular paper spray ionization (PSI) and nano electrospray ionization (nanoESI), DPS-MS allows fast and sensitive detection of oligosaccharides in biological samples having complex matrices (e.g., Tris, PBS, HEPES buffers or urine). When oligosaccharide sample is loaded onto the filter paper substrate (10 mm × 5 mm, height × base) made mostly of cellulose, oligosaccharides adsorb on the paper via hydrophilic interactions between oligosaccharides and cellulose. Salts and buffers can be washed away using an ACN/H(2)O (90/10 v/v) solution, While oligosaccharides can be eluted from the paper using a solution of ACN/H(2)O/formic acid (FA) (10/90/1 v/v/v) and directly spray-ionized from the tip of the paper. Various saccharides at trace levels (e.g., 50 fmol) in nonvolatile buffer can be quickly analyzed by DPS-MS (< 5 min per sample). DPS-MS is also applicable for direct detection of oligosaccharides from glycosyltransferase (GT) reactions, a challenging task which typically requires radioactive assay. Quantitative analysis of acceptor and product oligosaccharides shows increased product with increased GT enzymes used for the reaction, a result in line with radioactivity assay. This work suggests that DPS-MS has potential for rapid oligosaccharides analysis from biological samples.

This experiment shares the method development and analytical validation of an original, accurate and correct UV-Visible Spectrophotometric methods for the fixed dose assessment of Ramipril and Amlodipine besylate. The working solutions of Telmisartan and Ramipril were scanned at 240 nanometer and 210nanometer respectively. The regression strength of Amlodipine besylate and Ramipril over its absorbances take place as y=0.4291x0.0084 and y=0.0399x-0.310 respectively with a correlation coefficient (r2 ) of 0.9998 for Amlodipine besylate and 0.9993 for Ramipril. The intra-day precision in addition inter-day precision for Amlodipine besylate and its % RSD were obtained as 0.08% and 0.25% respectively. The intra-day precision in addition interday precision for Ramipril and% RSD were obtained as 0.16% and 0.24% respectively. The precise amount of tablet formulation were added which holds Alkaline (0.1 N Sodium hydroxide), Acidic (0.1 N Hydrochloric acid) reflux for 3 hours, 3% Oxydol at 50ºC, heat (60ºC), humidity (75 percentage Relative humidity) for 24 hr. and after the particular time diluted to distilled water, separated using Filter paper. From this stock solution, 5 mL section of the filtrate was pipetted out and further thinned with distilled water in a 100 mL standard flask (10 µg/mL). The standard stock solution of two drugs were prepared and compared against a label claim

Currently, filter paper assay (FPA) is used to measure the hydrolytic potential of cellulase enzyme mixtures that are used to hydrolyze a range of cellulosic substrates. However, some of the Whatma...

Over the past decades, paper-based lateral flow immunoassays (LFIAs) have been extensively developed for rapid, facile, and low-cost detection of a wide array of target analytes in a point-of-care manner. Conventional home pregnancy tests are the most significant example of LFAs, which detect elevated concentrations of human chorionic gonadotrophin (hCG) in body fluids to identify early pregnancy. In this work, we have upgraded these platforms to a higher version by developing a customized microfluidic paper-based analytical device (μPAD), as the new generation of paper-based point-of-care platforms, for colorimetric immunosensing. This will offer a cost-efficient and environmentally friendly alternative platform for paper-based immunosensing, eliminating the need for nitrocellulose (NC) membrane as the substrate material. The performance of the developed platform is demonstrated by detection of hCG (as a model case) in urine samples and subsequently indicating positive or negative pregnancy. A dual-functional silane-based composite was used to treat filter paper in order to enhance the colorimetric signal intensity in the detection zones of μPADs. In addition, microfluidic pathways were designed in a manner to provide the desired regulated fluid flow, generating sufficient incubation time (delays) at the designated detection zones, and consequently enhancing the obtained signal intensity. The presented approaches allow to overcome the existing limitations of μPADs in immunosensing and will broaden their applicability to a wider range of assays. Although, the application of the developed hCG μPAD assay is mainly in qualitative (i.e., positive or negative) detection of pregnancy, the semi-quantitative measurement of hCG was also investigated, indicating the viability of this assay for sensitive detection of the target hCG analyte within the related physiological range (i.e., 10–500 ng/mL) with a LOD value down to 10 ng/mL.

The present experiment works on routine initiation and scientific recognization of a typical, exact and meticulous UV-Visible Spectrophotometric process for the synchronous assessment of Amlodipine besylate and Olmesartan medoxomil. The working solutions of Amlodipine and Olmesartan medoxomil were scanned at 240 nanometer and 230 nanometer respectively. The regression strength of Amlodipine besylate and Olmesartan medoxomil over its absorbances were obtained as y = 0.068x-0.2182 and y = 0.067x0.0386 respectively with a correlation coefficient (r2) of 0.9995 for Amlodipine besylate and 0.9992 for Olmesartan medoxomil. The intra-day precision in addition inter-day precision for Amlodipine besylate and its % RSD were obtained as 0.15% and 0.39% individually. The intra-day precision in addition inter-day precision for Olmesartan medoxomil and % RSD were obtained as 0.39% and 0.14%, respectively. The precise amount of tablet formulation were added which holds Alkaline (0.1 N Sodium hydroxide), Acidic (0.1 N Hydrochloric acid) reflux for 3 hours, 3% Oxydol at 50ºC, heat (60ºC), humidity (75 Relative percentage humidity) for 24 hr and after the particular time quantity was dissolved with distilled water, separated using Filter paper. From this stock solution, 5 mL part of the filtrate was isolated and further diluted by distilled water in a 100 mL standard flask (10 µg/mL). The standard solution of two drugs were compared against a label claim.

Compared with traditional filter paper, a high-purity cellulose membrane prepared via a green pathway was used to enhance detection performance for cadmium ions. In this work, a simple, rapid, and ...

Problems of stability were found for biomarkers of alcohol consumption: ethyl glucuronide (EtG), ethyl sulfate (EtS), phosphatidylethanols (PEths), and fatty acid ethyl esters (FAEEs) in whole blood. The purpose of this study was to establish a method for the determination of these four kinds of ethanol's non-oxidative metabolites in dried blood spots (DBS) by liquid chromatography tandem mass spectrometry (LC-MS/MS), and to evaluate their stability. In this method, 50 μL of human blood was spotted onto a filter paper for DBS analysis. Samples were extracted by methanol, reconstituted by 2-propanol, and injected into the LC-MS/MS system. Limits of detection were among 0.5–50 ng/mL, and deviations in accuracy and precision were all lower than 15% at three quality control levels. The stability of the four kinds of ethanol non-oxidative metabolites in DBS was investigated during a 90-day range under three temperatures, −20 °C, 4 °C, and 25 °C. EtG and EtS showed a high level of stability in DBS in the 90-day range, regardless of the temperature. FAEEs were unstable after three days. PEths showed stability within 15 days in postmortem DBS and 60 days in antemortem DBS, respectively, at all temperatures.

This work presents a novel development that exploits the concept of in-situ gas-separation together with a specific enzymatic colorimetric detection to produce a portable biosensor called “Blood Alcohol Micro-pad” for direct quantitation of ethanol in whole blood. The thin square device (25 mm × 25 mm × 1.8 mm) comprises two layers of patterned filter paper held together with a double-sided mounting tape with an 8-mm circular hole (the headspace). In operation, the reagent is deposited on one layer and covered with sticky tape. Then 8 μL of a blood sample is dispensed onto the opposite layer and covered with sticky tape. Diffusion of ethanol across the 1.6 mm narrow headspace permits selective detection of ethanol by the enzymatic reagents deposited on the opposite layer. This reagent zone contains alcohol oxidase, horseradish peroxidase and 2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, as the chromogenic reagent. The color intensity, measured from the recorded digital image, resulting from the enzymatic assay of ethanol, correlates with the concentration of blood alcohol. The results obtained with spiked mice and sheep blood samples, using an external calibration in the range of 1–120 mg dL−1ethanol, gave recoveries of 93.2–104.4% (n = 12). The “Blood Alcohol Micro-pad” gave good precision with %RSD

Chlorination is a common and successful method for disinfection of water all around the world, especially in developing countries. However, this process can produce trihalomethanes (THMs) byproducts which are carcinogen. The major THM occurring in this process is chloroform. The purpose of this study was to design a simple equipment for colorimetric determination of chloroform in various water samples. The method is based on the colorimetric reaction of chloroform with resorcinol in strong basic medium on a filter paper. Response surface methodology (RSM) was employed to optimize the determination condition. The reagents were immobilized on filter paper and the color change was followed to quantify chloroform without using any analytical instrument. Detection limit and linear range of the proposed method were 0.007 mg/L and 0.011–1.192 mg/L, respectively for analysis of samples with volume of 2.0 L. The method was successfully applied to determine chloroform in different water samples and compared with GC-MS as a standard method. Employing the designed device, purge, trap and analysis steps were performed in a single run which can reduce the uncertainties originated by excessive steps of the analysis.

Detection of bacterial colonies in water is a pressing issue in recent times owing to its implications on human health, leading to an urgent need for low cost, disposable sensors. In this work, we report a disposable impedimetric sensor for detection of total bacterial colonies present in water samples. The sensor consists of a polyaniline coated filter paper functionalized with a homo-bi functional crosslinker, glutaraldehyde. Prior to the functionalization step, two Ag electrodes are deposited on the filter paper using conductive silver paste. The aldehyde groups of glutaraldehyde bind with the amine functional groups present on bacterial cell wall resulting in a change in dielectric constant, and consequently, the capacitive effect between the two Ag electrodes. Also, bacterial metabolism affects the medium conductivity and in turn, the medium resistance changes. The combined effect of changes in capacitive effect as well as resistance is reflected as a change in AC impedance measured using a frequency response analyzer (FRA). E. coli and Pseudomonas aeruginosa bacteria are detected in PBS buffer up to ~ 500 cfu/mL. Testing is also carried out by spiking tap water and grey water with known concentrations of bacteria samples. The detection limits obtained are 500 – 1000 cfu/mL with a response time of ~ 20 minutes. The developed sensor provides rapid, moderately sensitive, cost-effective solution for detecting total bacterial load in water samples.

By utilizing the coffee-ring effect and microfluidic paper-based analytical devices (µPADs), this study improved the sensitivity of the determination of norfloxacin in four different food matrices. Micro-PADs in this study were fabricated by designing and embedding wax channels onto cellulose-based filter paper through printing and subjecting the paper to heat to allow the wax to penetrate the paper. Determination of norfloxacin concentration in food samples was achieved by monitoring the colorimetric reaction that occurred between norfloxacin and the added iron (III) nitrate nonahydrate in 5 mM ammonia in each reaction chamber. A transition metal hydroxide was formed through this reaction that resulted in the formation of a solid precipitate to enable the antibiotic to bind to the iron molecule via coordination chemistry. This metal ion-antibiotic complex generated a visible color change. Following the colorimetric reaction, images were taken and subsequently analyzed via ImageJ to determine the relative pixel intensity that was used to infer norfloxacin concentration. The analytical sensitivity of this device was determined to be as low as 50 ppm when analyzing the inner-ring reaction, and as low as 5 ppm when analyzing the outer coffee ring thereby allowing for an alternative cheaper, faster, and more user-friendly method to detect norfloxacin than the conventional methods. PRACTICAL APPLICATION: This novel paper-based microfluidic device can achieve the detection of antibiotic residues in agrifoods in a faster, cheaper, and more user-friendly manner.

Background Dried specimens have been proposed in multiple environments to minimize costs associated with specimen storage and shipping in clinical studies. This report describes the development and validation of an automated method for qualitative toxicology screening of dried urine samples using LC–MS/MS. Methods Urine standards containing 41 compounds were prepared and applied to filter paper cards. Dried urine was eluted from the cards using a Dried Blood Spot (DBS) autosampler from Spark Holland, which was plumbed inline with a Thermo Scientific Turboflow chromatography system for subsequent MS/MS detection with selected reaction monitoring . Limits of detection, precision of peak areas, repeatability, and carryover studies were conducted. Concordance with a reference LC–MS/MS method using liquid samples was evaluated using remnant discarded specimens. Results The limit of detection ranged from 5 to 75 ng/mL for most compounds. At the LOD for each analyte, the peak area precision ranged from 8 to 29%. For 20 repeat injections of samples spiked at ±25% of the LOD, there was a 4% false positive rate for the 75% × LOD samples, and a 0.4% false negative rate for the +125% × LOD samples. In comparing 40 known positive specimens analyzed with the DUS method and a liquid urine reference method, there was 88% agreement. Analysis of 10 known negative specimens yielded negative results. There was no significant carryover detected up to 2000 ng/mL for any of the analytes in the assay. Conclusion Using a robotic DUS sampling an inline HTLC–MS/MS system, we have developed and validated a fully-automated and robust method for multi-analyte detection of drugs of abuse in dried urine specimens.

Blood filter paper strips are cost-effective materials used to store body fluid specimens under challenging field conditions, extending the reach of zoonotic pathogen surveillance and research. We describe an optimized procedure for the extraction of parasite DNA from whole blood (WB) stored on Type I Advantec Nobuto strips from both experimentally spiked and field-collected specimens from canine and skunks, respectively. When comparing two commercial kits for extraction, Qiagen’s DNeasy Blood &amp, Tissue Kit performed best for the detection of parasite DNA by PCR from Trypanosoma cruzi-spiked canine WB samples on Nobuto strips. To further optimize recovery of β-actin from field-collected skunk WB archived on Nobuto strips, we modified the extraction procedures for the Qiagen kit with a 90 °C incubation step and extended incubation post-addition of proteinase K, a method subsequently employed to identify a T. cruzi infection in one of the skunks. Using this optimized extraction method can efficaciously increase the accuracy and precision of future molecular epidemiologic investigations targeting neglected tropical diseases in field-collected WB specimens on filter strips.

The aim of this study was to further evaluate and optimize the Transwell® system for assessing the dissolution behavior of orally inhaled drug products (OIDPs), using fluticasone propionate as a model drug. Sample preparation involved the collection of a relevant inhalable dose fraction through an anatomical mouth/throat model, resulting in a more uniform presentation of drug particles during the subsequent dissolution test. The method differed from previously published procedures by (1) using a 0.4 µm polycarbonate (PC) membrane, (2) stirring the receptor compartment, and (3) placing the drug-containing side of the filter paper face downwards, towards the PC membrane. A model developed in silico, paired with the results of in vitro studies, suggested that a dissolution medium providing a solubility of about 5 µg/mL would be a good starting point for the method’s development, resulting in mean transfer times that were about 10 times longer than those of a solution. Furthermore, the model suggested that larger donor/receptor and sampling volumes (3, 3.3 and 2 mL, respectively) will significantly reduce the so-called “mass effect”. The outcomes of this study shed further light on the impact of experimental conditions on the complex interplay of dissolution and diffusion within a volume-limited system, under non-sink conditions.

This paper deals with the innovation of the Czech colorimetric biosensor Detehit designed for the simple, fast, and sensitive detection of nerve agents. The innovation is based on the use of an indicator consisting of a mixture of two triphenylmethane dyes, Guinea green B and a basic fuchsin, on a glass nanofiber filter paper carrier. The advantage of this solution is the blue–red color transition, which is much more visible than the white–yellow transition of other Detehit biosensors. The newly designed biosensor allows the users to visually detect (with the naked eye) the presence of the most significant paralytic substances (sarin, soman, cyclosarin, tabun, VX) in water at concentrations of at least 0.001 μg/mL. This biosensor design also enables one to detect these substances in air or on contaminated surfaces.

A procedure for the determination of phosphonylated tyrosine, a marker of exposure to organophosphorus nerve agents, in dried blood plasma spot (DBS) samples by means of liquid chromatography/tandem high-resolution mass spectrometry was developed. The DBS samples on Protein Saver 903 Card substrates were shown to be stable for two months on storage at 22 and 40°C. It was found that the temperature of storage has a high impact on the stability of the DBS samples: the analyte concentration in the samples stored at 40°C was about three times lower than that in the samples stored at room temperature. It was shown that the special Protein Saver 903 Card substrates could be replaced by an ordinary blue ribbon filter paper. In the latter case, the tyrosine adducts of nerve agents were reliably determined in the DBS samples stored for a month at room temperature (22°C). However, for storage at elevated temperatures (40°C), the use of filter paper substrates is not recommended. The proposed approach to storage of blood samples allows one to take and easily transport large series of samples and automate their analysis.

A novel all-in-one paper-based sampling concept for mass spectrometric bottom-up protein analysis is here demonstrated in a chip format integrating instant immunocapture, protein reduction, - alkylation and tryptic digestion all in-device. Conventional laboratory grade filter paper was coated with the polymer 2-hydroxyethyl methacrylate-co-2-vinyl-4,4-dimethyl azlactone (pHEMA-VDM) with a subsequent covalent immobilization of the monoclonal antibody E27 targeting the biomarker human chorionic gonadotropin (hCG). In-device protein reduction and alkylation was optimized with regards to reagent concentration and reaction pH. The sampling concept showed a high degree of performance between 10 and 1000 ng/mL (R2 > 0.99) by a five-point calibration curve sampled with hCG spiked to human serum samples and freshly collected whole blood samples, respectively. LOD (experimentally obtained at 100 pg/mL (2.64 pM/0.9 IU/L)) was demonstrated to be up to ten times lower with more than six times faster sample preparation than what has previously been reported for on-paper analysis of hCG in human serum samples.

High-purity cellulose membranes prepared via a green pathway were used to attempt to enhance their performance of glucose detection compared with that of traditional filter paper. In this work, cellulose-based strips (CBS) for the low concentration of glucose detection have been designed based on a fast, sensitive, and easy enzyme colorimetric assay from porous and high-purity cellulose membranes (CM). Different from the traditional paper-based sensors that were made of commercially available filter paper, the cellulose-based membranes matrix was fabricated by a "green" route in that cellulose was dissolved in an aqueous NaOH/urea solution, and then modified by the sodium periodate oxidation method to immobilize the glucose oxidase (GOX) and horseradish peroxidase (HRP) with Schiff-base reaction. The structure and properties of CM and CBS were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray mapping (EDS), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), etc. SEM images showed a porous, interpenetrating structure of CM, which benefited the enzyme immobilization and enzymatic reaction. When glucose solution was dropped onto the CBS, the color change from colorless to blue was only 5 min. The limit of detection (LOD) is 0.45 mM in the linear range of glucose from 1 to 11 mM. Moreover, the CBS had also been successfully used for glucose determination in real urine samples, and the color changes can be easily recorded by a simple camera to achieve the semiquantitative detection of glucose. This work provided a new design strategy for the cellulose-based functional materials which could be applied in biosensors, drug carriers, and biomedicine.

Monitoring of copper(II) ion is critical for water safety. Herein, a solid phase extraction (SPE) column filled with home-made sulfonated PS-DVB microspheres was adopted to eliminate interference from other co-existing ions. Meanwhile, 1-(2-pyridylazo)-2-naphthol (PAN) as colorimetric reactant was dispersed in polyvinyl butyral (PVB) and immobilized on the filter paper. The as-fabricated paper-based microfluidic analytical device (μPAD) combined with home-made SPE column was utilized for the selective and quantitative determination of copper(II) ion. The selectivity and sensitivity for copper(II) ion were significantly enhanced by SPE-combined μPAD. The sensor has a noticeable color change in the presence of copper(II) ion. The limit of detection was as low as 0.340 μM, which is much less than the drinking water guidelines in many countries and organizations. This technology is convenient and does not need any expensive instrumentation and professional skills. It is easily used to achieve rapid and on-site assessment of copper(II) ion in real-world situations.

BACKGROUND: The inhibitory effect of a moisture‐absorbent sodium polyacrylate (SPA), that is commonly used in disposable diapers, on the bio‐hydrogen (H₂) generation from waste diaper‐like material (WDM) was assessed in dark fermentation studies. Three types of treatments were evaluated in batch bioreactors at 37 °C: mixture of bond paper and filter paper (WDM, no SPA), SPA alone (only SPA or control), and WDM spiked with SPA [paper plus sodium polyacrylate hydrogel (WDM‐SPA)]. The WDM simulated the cellulosic fraction of diaper composition. RESULTS: The units with only SPA did not produce H₂. The WDM‐SPA units exhibited H₂production 25% lower than those of bioreactors loaded with only WDM but no SPA. Cumulative H₂ production was 0.03, 4.22 and 5.50 mmolH₂ gTS–¹ for the SPA, WDM‐SPA and WDM reactors, respectively (0.04, 5.90 and 8.77 mmolH₂ gVS–¹; 0.89, 132.19 and 196.45 NmLH₂ gVS–¹). BioH₂ generation was related to predominance of the fermentation route that produces 1 mol L–¹ of butyric acid (HBu) plus 2 mol L–¹ H₂ in the WDM and WDM‐SPA units, as suggested by the ratio A:B (acetic: butyric acids; A:B

We report the method for fabrication and validation of a standalone handheld optical biosensor for non-invasive monitoring of glucose using saliva. For this, a biodegradable, low-cost test strip for glucose was developed by co-immobilizing glucose oxidase enzyme and bromocresol purple pH sensitive dye. The enzymatic reaction produced pH change and, thus, a change in color of a filter paper strip, which was detected by a standalone electronic meter. The in-house developed meter consisted of an optically isolated region in the chassis for inserting the test strip along with the sample to avoid interferences from ambient wind and light. The developed biosensor had a wide detection range of detection between 32- and 516-mg/dL glucose concentration while the sensitivity of detection was 1.0 mg/dL/count at a limit of detection (LOD) of 32 mg/dL within a response time of 15 s. The device along with strips was validated on clinical samples while comparing salivary glucose level with that of blood glucose level using a commercial glucometer. A very good correlation was found for diabetic individuals (0.80), whereas it was less significant (0.53) for non-diabetic individuals. The device passed Clarke’s error grid analysis and hence should be medically acceptable. This simple and low-cost setup should be ideally suited for mass screening of diabetes, apart from being used as a self-monitoring device in a non-invasive and painless manner.

The present work describes a unique method for the purification and concentration of catechins from Camellia sinensis. The extracted plant products after using hot water were filtered and fed into a membrane separation process to separate catechins. Samples collected at various stages of processing were filtered through an ordinary filter paper and used for HPLC analysis. The permeate flux increased from 9.23 × 10−6 to 17.8 × 10−6 m3 m−2 s−1 when cross flow velocity increased from 2 to 6 LPM at 30 Psi pressure. Aqueous permeate obtained from the membrane cell was concentrated and decaffeinated to get purified catechins. Combining all the catechin compounds a final product containing 72% of catechins was obtained. The catechins thus extracted were utilized in the preparation of a pharmaceutical supplement comprising an effective amount of 30–80% (w/w) catechin component mixture and 5–50% (w/w) starch as filler along with/without the inert materials as additives.

© 2019 Elsevier B.V. The detection and analysis of explosives and explosive-related compounds is a heightened priority in recent years for homeland security and counter-terrorism applications. This study aimed to evaluate the use of a commercial Lab-On-a-Chip (LOC) instrument for the analysis of explosive vapours, with the long-term goal of developing a portable instrument for passively detecting explosives in air samples. A simple method to collect explosive vapour residues was developed using a glass vial containing varying amounts of the target explosives (1 mg/mL). Standards were diluted to the desired concentration in 150 μL of acetone to facilitate the evaporation. The top of the vial was covered with a circular 0.5 cm diameter filter paper and exposed to a range of temperatures from 22 °C to 80 °C for 15 min. Following evaporation, the filter paper chads were folded and inserted into the LOC wells containing the separation buffer for the analysis, avoiding any further extraction step. After successfully separating and detecting eight explosives via liquid analysis, three explosives were chosen as targets for the vapour analysis experiments. 1,3,5-Trinitrobenzene (TNB), 2,4,6-Trinitrotoluene (TNT), and 2,4,6-Trinitrophenylmethylnitramine (Tetryl) were successfully separated, detected and identified following the vapour extraction of explosive standards onto filter paper chads. Limits of detection for the liquid analysis were demonstrated to be 2.32 ng for TNB, 2.35 ng for Tetryl, and 3.25 ng for TNT. The minimum detectable mass found for the vapour analysis was 6.03 for TNB, 9.99 ng for TNT, and 14.22 ng for Tetryl. The average recovery from the paper chads was 29% for Tetryl, 47% for TNB, and 75% for TNT (n = 4), comparable with findings from previous studies. Results show that a minimum temperature of 40 °C is necessary to vaporize the compounds using acetone, while the best results were achieved when heating the vial to 80 °C. The use of a filter paper to collect the explosives residues, avoiding any additional extraction step, and the ability to analyze these compounds using a LOC instrument, makes this approach a future alternative method for explosive residues detection in the headspace.

Inspired by dried blood spots (DBS), “dried spots of herbal medicines” (DSHM) concept was proposed here. In response to this superior sampling means, a new platform integrating dried spot, serially coupled reversed phase liquid chromatography and hydrophilic interaction liquid chromatography (RPLC-HILIC), and tandem mass spectrometry (MS/MS), was configured for directly, comprehensively chemical profiling of HM-derived liquid matrices. As an important original source of Cistanches Herba (Chinese name: Roucongrong) that is a well-known tonic HM, Cistanche sinensis (Csi) was employed to illustrate and validate the applicability. Dried spots (I.D. 3.0 mm) were prepared by loading 2 μL aliquots of Csi extract onto filter paper. Each dried spot was packed into an in-line filter holder (I.D. 3.0 mm × 4.0 mm) and then inserted behind the auto-sampler of a well-defined instrumentation named RPLC-HILIC–MS/MS. Hybrid ion trap-time of flight MS and hybrid triple quadrupole-linear ion trap MS were deployed in combination for the in-depth MS/MS data acquisition of diverse chemical families, such as phenylethanoid glycosides, lignans, iridoids, amino acids, and so forth. To assist chemical profiling, an in-house chemical library was built by collecting as much prior knowledge as possible. A total of 88 components were detected and tentatively annotated in Csi by matching their multi-stage MS spectra with those of authentic standards and literature data. Collectively, DSHM carried all merits of DBS, and the integrative dried spot-RPLC-HILIC-MS/MS platform was a promising analytical tool for direct chemical analysis and rapid quality evaluation of HMs, in particular those traditional Chinese medicine injections.

Microfluidic paper-based analytical devices (μPADs) for detection of hydrogen peroxide and glucose have been developed. The analytical performance of colorimetric detection using the conventional starch-iodine color reaction has been significantly improved by using gelatin as the surface modifier which retains the enzyme activity in the dry filter paper strip, improves antioxidability, as well as decreases the strong background signal. Under optimal conditions, the color intensities show a good linear relationship with glucose concentration ranging from 0.5 to 5 mM and hydrogen peroxide concentration from 0.5 to 6 mM, with the detection limit of 0.05 mM and 0.1 mM, respectively. In addition, the accuracy of colorimetric sensor has been successfully assessed in detecting glucose from real human serum samples and recovery value ranges from 95.7% to 97%, which are approaching to the glucose oxidase endpoint. The new colorimetric assay exhibits high sensitivity, good selectivity, acceptable stability and reproducibility. The present approach is promising for monitoring glucose for point of care diagnostic applications, especially in regions with resource-limited settings.

A new highly selective and sensitive dual-mode sensor 3TD based on the conjugate of oligothiophene and barbituric acid moiety was developed for colorimetric and turn-on fluorescent detection of CN─. The sensor 3TD exhibited high specificity towards CN─ by interrupting its own ICT producing thereupon a large blue-shift in UV–Vis spectrum and remarkable “turn-on” fluorescence emission. The detection limit was 2.26 × 10─7 M, which is quite lower than the permissible level of CN─ in drinking water according to the WHO. The fluorescent detection of CN─ was well demonstrated by filter paper strips and silica coated TLC plates. Moreover, the sensor was also used to detect CN─ in environmental water and agro-products with satisfactory results. Most importantly, in terms of these advantages of colorimetric and turn-on fluorescent dual-mode, immediate response, excellent selectivity, high sensitivity, low cytotoxicity, and good biocompatibility, the sensor 3TD was successfully applied into CN− imaging in living cells, demonstrating its excellent value in practical application.

Body surface mucus was scraped off from white croaker Pennahia argentata after washing with two different procedures, suspended in cold water and filtered through a filter paper. The filtrate thus obtained was lyophilized and defined as the fish body surface substances. The relative level of the substances obtained after high-pressure water washing was 28.8% and significantly lower than those obtained after conventional washing (68.8%) and without washing (100%). The breaking strength of thermally induced gels prepared by pre-heating at 65 °C mimicking modori for 60 min after the high-pressure water washing was 3.8 N and was significantly higher than that after the conventional washing (2.6 N) and without washing (2.1 N). These results suggest that rheological properties of thermally induced gels can be improved with an extensive washing of fish material. The degradation of myosin heavy chain was recognized, when the water soluble fraction of the lyophilized powder of the fish body surface mucus was added into the ordinary muscle homogenate at around 60 °C and pH 8.15, suggesting that proteases were present in the fish body surface mucus. Such novel findings are useful for avoiding the modori phenomenon and thus improving the quality of surimi-based products.

Objective: This study aimed to evaluate of the tissue dissolution capability of 3% of sodium hypochlorite, 5%pomegranate, and 5% miswak.Methods: 45 freshly extracted premolar teeth were used. The teeth were grouped into three groups (n=15) Group I: The pulp tissue was immersed in 3% sodium hypochlorite irrigating solution. Group II: The pulp tissue were immersed in Punicagranatum (5%pomegranate) Nano particles irrigating solution. Group III: The pulp tissue were immersed in Salvadorapersica (5%miswak) Nano particles irrigating solution. The pulp tissue obtained was inserted into a small plastic test tube and 10ml of the irrigating solution were added to it and stored for 15 min. The ultrasonic tip were inserted inside the tube with irrigating solution and allowed to work for 1 minute to achieve proper agitation. After 15 min the solution was filtered through absorbing filter paper for 3 min to remove any excess moisture and left the sample to dry. Then the weight of the residual pulp tissue was measured and the difference between the initial and final weight was used to calculate the weight loss that were represent the dissolving power of each solution.Results: The highest value of dissolution percentage was found in Sodium hypochlorite group (98%), followed by Pomegranate group (78.3%). while the least value was found in Miswak group (66.8%). p= ≤0.001.Conclusion: On contrary of miswak, Pomegranate gives promising results in relation to NaOCl in terms of tissue dissolving capacity.

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 (

This manuscript reports on a simple paper-based bienzymatic colorimetric assay for sarcosine as an important urinary biomarker of prostate cancer. All required assay reagents are pre-deposited on hydrophilic filter paper spots surrounded by a hydrophobic barrier. Sarcosine in the sample solution is selectively oxidized in the presence of sarcosine oxidase (SOx), resulting in the formation of hydrogen peroxide, which is subsequently detected through the horseradish peroxidase (HRP)–catalyzed conversion of the colorless indicator 3,3’,5,5’-tetramethylbenzidine (TMB) into its blue-colored oxidation product. By the modification of the paper with positively charged poly(allylamine hydrochloride) (PAH), a linear response to sarcosine between 0 and 10 μM and a significant lowering of the limit of detection (LOD) (0.6 μM) compared to the unmodified paper substrate (12.6 μM) has been achieved. The improvement of the LOD was attributed to the fact that the presence of the polymer limits the enzyme-driven colorimetric reaction to the surface of the paper substrate, resulting in stronger color development. In experiments in artificial urine matrix, the bicarbonate anion was identified as an inhibitor of the colorimetric reaction. This inhibition was successfully eliminated through on-device sample pH adjustments with pH-buffer components pre-deposited onto assay devices. The LOD for sarcosine achieved in artificial urine matrix (2.5 μM) is below the 5 μM threshold value for this urinary biomarker required for diagnostic purposes. Finally, good selectivity over all 20 natural amino acids and satisfactory long-term storage stability of reagent-modified paper substrates at − 20 °C for a period of 50 days were confirmed.

Rationale To open up new ways for matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS)-based patient screening, blood serum is the most preferred specimen because of its richness in patho-physiological information and due to ease of collection. To overcome deleterious freeze/thaw cycles and to reduce high costs for shipping and storage, we sought to develop a procedure which enables MALDI-MS protein profiling of blood serum proteins without the need for serum freezing. Methods Blood sera from patients/donors were divided into portions which after pre-incubation were fast frozen. Thawed aliquots were deposited on filter paper discs and air-dried at room temperature. Intact serum proteins were eluted with acid-labile detergent-containing solutions and were desalted by employing a reversed-phase bead system. Purified protein solutions were screened by MALDI-MS using standardized instrument settings. Results MALDI mass spectra from protein solutions which were eluted from filter paper discs and desalted showed on average 25 strong ion signals (mass range m/z 6000 to 10,000) from intact serum proteins (apolipoproteins, complement proteins, transthyretin and hemoglobin) and from proteolytic processing products. Semi-quantitative analysis of three ion pairs: m/z 6433 and 6631, m/z 8205 and 8916, as well as m/z 9275 and 9422, indicated that the mass spectra from either pre-incubated fast-frozen serum or pre-incubated dried serum spot eluted serum contained the same information on protein composition. Conclusions A workflow that avoids the conventional cold-chain and yet enables the investigation of intact serum proteins and/or serum proteolysis products by MALDI-MS profiling was developed. The presented protocol tremendously broadens the clinical application of MALDI-MS and simultaneously allows a reduction in the costs for storage and shipping of serum samples. This will pave the way for clinical screening of patients also in areas with limited access to health care systems, and/or specialized laboratories.

Several different diagnostic tests have been reported for rapid, sensitive, and economical detection of bacterial pathogens, but most lack widespread and practical use in the clinic. In this study, we used anthocyanins from red cabbage (Brassica oleracea) as a natural pH indicator and, for the first time, incorporated this agent into a simple, rapid, and economical colorimetric strategy for the detection of Helicobacter pylori (H. pylori) (RCE@test). We prepared two sets of RCE@test solutions (test 1 is purple, and test 2 is blue) in different forms, including liquid, adsorbed filter paper, and agar, and investigated the performance of each RCE@test as a function of the test volume, H. pylori concentration, and reaction time. To elucidate the effect of the pathophysiological environment on these RCE@tests, H. pylori in an artificial gastric fluid was also detected. The 10 and 1 CFU/mL H. pylori suspensions were detected in 15 min and 3 h, respectively, and the limit of detection was determined down to 1 CFU/mL. We experimentally demonstrated the advantages of the RCE@test for detection of H. pylori by comparing it to a commercially available rapid urease test, the CLO test (Campylobacter-like organism test). In addition to colorimetric detection by the naked eyes, RGB (Red Green Blue) and Delta-E analysis in image-processing software was run to quantitatively monitor changes of color in the RCE@test using a smartphone application. Finally, we propose that this test provides simple, effective, rapid, and inexpensive detection and that it can be easily implemented for clinical use. 2020 BAGEP Award of the Science Academy; Turkish Academy of Sciences (2018 TUBA GEBIP Award) This work was supported by the 2020 BAGEP Award of the Science Academy and Turkish Academy of Sciences (2018 TUBA GEBIP Award). We would like to thank Mucahit Osman Turkan and Busra Aydin for their assistance in drawing and designing TOC. WOS:000643539400033 2-s2.0-85104943598 PubMed: 33825433