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Rapid, sensitive, point-of-care detection of pathogenic bacteria is important for food safety. In this study, we developed a novel quantum dot nanobeads-labelled lateral flow immunoassay strip (QBs-labelled LFIAS) combined with strand displacement loop-mediated isothermal amplification (SD-LAMP) for quantitative Salmonella Typhimurium (ST) detection. Quantum dot nanobeads (QBs) served as fluorescence reporters, providing good detection efficiency. The customizable strand displacement (SD) probe was used in LAMP to improve the specificity of the method and prevent by-product capture. Detection was based on a sandwich immunoassay. A fluorescence strip reader measured the fluorescence intensity (FI) of the test (T) line and control (C) line. The linear detection range of the strip was 102–108 CFU·mL−1. The visual limit of detection was 103 CFU·mL−1, indicating that the system was 10-fold more sensitive than AuNPs-labelled test strips. ST specificity was analyzed in accordance with agarose gel outputs of PCR and SD-LAMP. We detected ST in foods with an acceptable recovery of 85%–110%. The method is rapid, simple, almost equipment-free, and suitable for bacterial detection in foods and for clinical diagnosis.

Background: The fruit pulp decoction of Crescentia cujete, commonly known as calabash, is traditionally used for the treatment of several respiratory diseases and is available as syrup formulations. Unfortunately, there is no detailed investigation on analytical methods for warranting the quality of these products. Aim and objective: To develop and validate an appropriate analytical method for the simultaneous quantification of transcinnamic acid, 4-hydroxybenzoic acid, verbascoside and 6-epi-aucubin in the decoction and commercial cough syrups of Crescentia cujete fruit. Materials and methods: A reversed-phase ultra-high-performance liquid chromatographic method coupled to a diode array detector (UPLC-DAD) was validated following the ICH guidelines. The chromatographic analysis was performed using a C18 column, the mobile phase system consisted of water and acetonitrile containing 0.1% formic acid, and UV chromatograms were recorded from 200 to 400 nm. Results: A new UPLC-DAD method was validated for the simultaneous quantification of trans-cinnamic acid, 4- hydroxybenzoic acid, verbascoside and 6-epi-aucubin in calabash-derived products. After successful validation, this method was applied for the quantification of the selected chemical markers in an in-house decoction and three commercial cough syrups. Among the selected chemical markers, 6-epi-aucubin was the main compound in the calabash decoction, while trans-cinnamic acid and 4-hydroxybenzoic acid were the major compounds in the commercial products. Verbascoside and 6-epi-aucubin were below the limit of quantification in all syrup samples. Conclusion: The proposed method was successfully applied for the analysis of three commercial syrup formulations and can be useful for standardization and quality control of raw and pharmaceutical calabash preparations.

Introduction Mycotoxins are toxic metabolites produced by fungi that commonly contaminate foods. As recommended by the World Health Organization, total diet study (TDS) is the most efficient and effective way to estimate the dietary intakes of certain chemical substances for general populations. It requires sensitive and reliable analytical methods applicable to a wide range of complex food matrices and ready-to-eat dishes. Objectives A novel strategy with high selectivity and sensitivity, incorporating three methods based on ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS), was designed for measuring 43 mycotoxins in dietary samples in a China TDS. Methods The 43 mycotoxins were divided into 3 groups for analysis to achieve better performance. For each group, an UHPLC-MS/MS method was developed to determine the target compounds after clean-up by solid phase extraction. A total of 21 isotope internal standards were employed for accurate quantitation. Method validation in terms of linearity, selectivity, sensitivity, accuracy, and precision was performed for all the 43 mycotoxins in 12 complex food matrices. Results The limits of detection (LODs) and limits of quantitation (LOQs) were 0.002–1 ng mL−1 and 0.006–3 ng mL−1, respectively. The method recoveries of the 43 mycotoxins spiked in 12 food categories were in the range of 60.3%–175.9% after internal standard correction, with relative standard deviations (RSDs) below 13.9%. For practical application, this method was utilized for 72 dietary samples collected from 6 provinces in the 6th China TDS. More than 80% of the samples were found contaminated by mycotoxins. DON, SMC, FB1, ZEN, BEA, ENNB1, and ENNB were most detected. Conclusions The proposed methods with high sensitivity, accuracy, and robustness provide powerful tools for multi-mycotoxin monitoring and dietary exposure assessment, allowing 43 mycotoxins, including some emerging mycotoxins, to be accurately investigated in a total diet study for the first time.

Rapid screening of foodborne pathogens is of great significance to ensure food safety. A microfluidic biosensor based on immunomagnetic separation, enzyme catalysis and electrochemical impedance analysis was developed for rapid and sensitive detection of Salmonella typhimurium. First, the bacterial sample, the magnetic nanoparticles (MNPs) modified with capture antibodies, and the enzymatic probes modified with detection antibodies and glucose oxidase (GOx) were simultaneously injected into the microfluidic chip, followed by mixing and incubation to form MNP-bacteria-probe sandwich complexes. Then, glucose with high impedance was injected into the chip and catalyzed by the GOx on the complexes into hydrogen peroxide with high impedance and gluconic acid with low impedance, which was finally measured using the low-cost interdigitated microelectrode and the electrochemical impedance analyzer to determine the target bacteria. Under the optimal conditions, this biosensor could quantitatively detect Salmonella typhimurium at the concentrations from 1.6 × 102 CFU/mL to 1.6 × 106 CFU/mL in 1 h with the low detection limit of 73 CFU/mL. Besides, this biosensor was demonstrated with good feasibility for practical applications by detecting the Salmonella typhimurium spiked chicken meat samples.

A gold nanoparticle (AuNP) aggregation-induced colorimetric aptasensing method for quantitative detection of sulfadimethoxine (SDM) with a smartphone was developed. AuNPs were complexed with aptamers which protected AuNPs from aggregating in high-concentration salt solutions. In the presence of SDM, SDM bound with the aptamer on the surface of AuNPs with higher affinity, which competitively desorbed the aptamer from the AuNP surface and resulted in AuNPs aggregation, accompanied with a color change from red to purple-blue. The R, G and B values of images taken by a smartphone camera were analyzed with an app on the smartphone, and were utilized for quantitative analysis of SDM. Under the optimized conditions, the colorimetric aptasensing method using a smartphone showed high sensitivity for SDM, with the limit of detection of 0.023 ppm, lower than the allowed maximum SDM residue limit. This study provides a simple, fast, and easy to read method for on-site quantitative biochemical and cellular analysis.

A simple and efficient dithizone-functionalized solid-phase extraction (SPE) procedure, online coupled with high-performance liquid chromatography (HPLC)-inductively coupled plasma mass spectrometry, was developed for the first time for enrichment and determination of ultra-trace mercury (Hg) species (inorganic divalent Hg (Hg(II)), methylmercury (CH3Hg(II)) and ethylmercury (C2H5Hg(II)) in cereals and environmental samples. In the proposed method, functionalization of the commercial C18 column with dithizone, enrichment, and elution of the above Hg species can be completed online with the developed SPE device. A simple solution of 2-mercaptoethanol (1% (V/V)) could be used as an eluent for both the SPE and HPLC separation of Hg species, significantly simplifying the method and instrumentation. The online SPE method was optimized by varying dithizone dose, 2-mercaptoethanol concentration, and sample volume. In addition, the effect of pH, coexisting interfering ions, and salt effect on the enrichment was also discussed. Under the optimized conditions, the detection limits of Hg species for 5 mL water sample were 0.15 ng/L for Hg(II), 0.07 ng/L for CH3Hg(II), and 0.04 ng/L for C2H5Hg(II) with recoveries in the range of 85%–100%. The developed dithizone-functionalized C18 SPE column can be reused after a single functionalization, which significantly simplifies the enrichment step. Moreover, the stability of Hg species enriched on the SPE column demonstrated its suitability for field sampling of Hg species for later laboratory analysis. This environment-friendly method offers a robust tool to detect ultra-trace Hg species in cereals and environmental samples.

The protein complex of recombinant human insulin-like growth factor-1 and insulin‑like growth factor binding protein‑3 (rhIGF-1/rhIGFBP-3; mecasermin rinfabate), is an investigational product for the prevention of complications of prematurity. Delivery of rhIGF-1/rhIGFBP-3 is by continuous central line intravenous infusion in preterm infants until endogenous IGF-1 production begins. Protein-specific analytical methodologies were developed to evaluate the compatibility of rhIGF- 1/rhIGFBP-3 at low protein concentrations (∼2.5-10 μg/mL) expected when co-administered with other required medications in the NICU. Highly sensitive detection of the biologic potential degradants (fragments) and/or molecular modifications (oxidized species, aggregates) required the use of reversed-phase high-performance liquid chromatography and size-exclusion ultra-performance liquid chromatography coupled with mass spectrometric detection. We report on the quantification of rhIGF-1/rhIGFBP-3, its components and degradants, to a limit of quantitation of 3.1 μg/mL upon mixing with 24 commonly administered neonatal medications. Methods developed for the rhIGF-1/rhIGFBP-3 admixtures, optimized in studies with furosemide, caffeine citrate and ampicillin, demonstrated good reproducibility, linearity, and limit of detection/quantitation. Using these methods, no increase in degradation of rhIGF-1/rhIGFBP-3 components and no increase in oxidation or aggregation level was observed with caffeine citrate, while admixtures of rhIGF-1/rhIGFBP-3 with ampicillin yielded lower mass recovery of rhIGF-1/rhIGFBP-3 components, which likely resulted from adduct formation. Furosemide was found to be physically incompatible with rhIGF-1/rhIGFBP-3. Our findings support the use of these methodologies for detection of protein modifications under various clinical administration conditions, and additionally supplement physical compatibility data studies of ultra-low concentrations of rhIGF-1/rhIGFBP-3 post co-administration to preterm infants with other medications (manuscript in-preparation).

Foodborne pathogenic bacteria have been considered as a major risk factor for food safety. It is of great significance to carry out in-field screening of pathogenic bacteria to prevent the outbreaks of foodborne diseases. In this study, a portable lab-on-a-disc platform with a microfluidic disc was developed for rapid and automatic detection of Salmonella typhimurium using a nickel nanowire (NiNW) net for effective separation of target bacteria, horseradish peroxidase nanoflowers (HRP NFs) for efficient amplification of biological signals, and a self-developed smartphone APP for accurate analysis of colorimetric images. First, the microfluidic disc was preloaded with reagents and samples and centrifuged to form one bacterial sample column, one immune NiNW column, one HRP NF column, two washing buffer columns and one tetramethylbenzidine (TMB) column, which were separated by air gaps. Then, a rotatable magnetic field was specifically developed to assemble the NiNWs into a net, which was automatically controlled by a stepped motor to successively pass through the sample column for specific capture of target bacteria, the HRP NF column for specific label of target bacteria, the washing columns for effective removal of sample background and non-specific binding NFs, and the TMB column for colorimetric determination of target bacteria. The color change of TMB from colorless to blue was finally analyzed using the smartphone APP to quantitatively determine the target bacteria. This lab-on-a-disc platform could detect Salmonella typhimurium from 5.6 × 101 CFU/20 μL to 5.6 × 105 CFU/20 μL in 1 h with a lower detection limit of 56 CFU/20 μL. The recovery of target bacteria in spiked chicken samples ranged from 97.5% to 101.8%. This portable platform integrating separation, labeling, washing, catalysis and detection onto a single disc is featured with automatic operation, fast reaction, and small size and has shown its potential for in-field detection of foodborne pathogens.

Indole-3-carbinol (I3C), an important anticancer compound found in broccoli, has attracted considerable attention. The rapid extraction and accurate analysis of I3C in the pharmaceutical industry in broccoli is challenging as I3C is unstable at low pH and high temperature. In this study, a rapid, accurate, and low-cost ultrasound-assisted dispersive-filter extraction (UADFE) technique based on poly(deep eutectic solvent)-graphene oxide (PDES-GO) adsorbent was developed for the isolation and analysis of I3C in broccoli for the first time. PDES-GO with multiple adsorption interactions and a fast mass transfer rate was synthesized to accelerate adsorption and desorption. UADFE was developed by combining dispersive solid-phase extraction (DSPE) and filter solid-phase extraction (FSPE) to realize rapid extraction and separation. Based on the above two strategies, the proposed PDES-GO-UADFE method coupled with high-performance liquid chromatography (HPLC) allowed the rapid (15–16 min), accurate (84.3–96.4%), and low-cost (adsorbent: 3.00 mg) analysis of I3C in broccoli and was superior to solid-phase extraction, DSPE, and FSPE methods. The proposed method showed remarkable linearity (r=0.9998; region: 0.0840–48.0 μg/g), low limit of quantification (0.0840 μg/g), and high precision (relative standard deviation ≤ 5.6%). Therefore, the PDES-GO-UADFE-HPLC method shows significant potential in the field of pharmaceutical analysis for the separation and analysis of anti-cancer compounds in complex plant samples.

Rapid and accurate detection of immunoglobulin E (IgE) in serum and reduction of serum dosage are of great significance for clinical detection. Herein, we described a rapid magnetic separation of IgE from patient serum based on Fe3O4@SiO2-NTA@026 sdab as the capture probe and multiple horseradish peroxidase (HRP)-labeled antibodies linked gold nanoparticles (AuNPs) as chemiluminescence (CL) signal amplifier for ultrasensitive detection of total IgE. Results showed that the limit of detection of our immunosensor system in serum samples was 0.03 kU/L, which is lowest in comparison with current methods, and far lower than that of ImmunoCAP for IgE detection (0.1 kU/L). Furthermore, our immunosensor possessed satisfied repeatability and accuracy, as well as good stability. In comparison with the ImmunoCAP for the quantitative detection of IgE, highly consistent results were achieved in 20 serum samples. Specially, this method was also successfully utilized for assessing the IgE traces in breast cancer patients, which provides a new idea for the diagnosis of early cancer. Therefore, we believe that such versatile immunosensor will offer an alternative method for the on-site monitoring and determination of various IgE-related diseases.

Because the widely used perfluorooctane sulfonate (PFOS) is harmful to both environment and human health, it is of great significance and urgency to develop sensitive and selective sensors for the detection of trace PFOS in water. In this study, a tetraphenylethylene-derived macrocycle BowtieCyclophane has been developed as a fluorescent sensor based on aggregation-induced emission enhancement and fluorochromism. Sensitive detection of PFOS has been achieved with a limit of detection (LOD) of 47.3 ± 2.0 nmol/L (25.4 ± 1.1 μg/L) accompanied by visual fluorescence color changes.

As a neglected member of the platinum group elements, osmium, the metal with the highest density in the earth, is very suitable for the preparation of a peroxidase with high catalytic activity and stability, and can also be associated with the development of a sensor. In this study, we accessed Os nano-hydrangeas (OsNHs) with one-pot synthesis and utilized them in a bifunctional immunosensor that can present both catalytic chromogenic and tinctorial signal for nanozyme-linked immunosorbent assay (NLISA) and lateral flow immunoassay (LFIA) for use in folic acid (FA) detection. In the OsNHs-NLISA, the linear range is from 9.42 to 167.53 ng mL−1. The limit of detection (LOD) is 4.03 ng mL−1 and the IC50 value is 39.73 ng mL−1. In OsNHs-LFIA, the visual cut-off value and limit of detection (v-LOD) are 100 ng mL−1 and 0.01 ng mL−1, respectively. Additionally, the outcome from the specificity and spiked sample analysis offered recovery from the spiked milk powder sample ranging from 93.9 to 103.6% with a coefficient of variation under 4.9%, compared with UPLC-MS/MS for a correlation of R2 = 0.999 and admirable validation. The promising application of the OsNHs can also be used in other bioprobes, and this bifunctional immunosensor analysis mode is suitable for diversified analytes.

In this work, a rapid and simplified method for extracting SARS-CoV-2 RNA from whole wastewater using a magnetic beads-based protocol is presented. The described method involves the centrifugation of a 50-mL aliquot of raw wastewater influent for 5 min to obtain a 500-μL pellet, which is eluted with 2 mL of a Tween®20-based elution buffer; 1 mL of the elute is extracted for RNA using a direct magnetic bead-based extraction method. RNA recovery was examined in several bench-scale experiments using heat-inactivated SARS-CoV-2 (HI-SCV-2) spiked into raw wastewater to assess the effects of different solids pellet : buffer ratios, inhibition mitigation strategies, and varying levels of total suspended solids. When the method was assessed using an influent wastewater sample known to contain SARS-CoV-2, the viral signal was detected in all five biological replicates, whereas direct extraction of 1-mL aliquots of the raw wastewater resulted in a 40% viral detection rate. The experimental method limit of detection (MLOD) using HI-SCV-2 spiked into raw wastewater was 50 GU mL−1 with a 95% limit of detection. Using the described protocol, the presence of SARS-CoV-2 RNA was verified in wastewater collected from wastewater treatment facilities (WWTFs) in Atlantic Canada over a period of 15 weeks during the rise and fall of a COVID-19 outbreak. This method is effective and rapid and could provide potential application for laboratories with limited resources. Of approximately 50 methods that have been developed for measuring SARS-CoV-2 in wastewater referenced in the literature, this is the first to advance a robust magnetic beads-based RNA extraction technique from whole wastewater without extensive sample pre-treatment. The novel application of this method in the rapid extraction of SARS-CoV-2 RNA from municipal wastewater is an indispensable tool to potentially understand COVID-19 infection occurrence within communities.

Metabolomics-based analytical strategy has showed superiority on non-targeted screening of contaminants, especially for unknown and unexpected (U&U) contaminants in the field of food safety, but data analysis is often the bottleneck of the strategy. In this study, a novel metabolomics-based analytical method via searching for marker compounds was developed, on the basis of ultrahigh-performance liquid chromatography-tandem mass spectrometer (UHPLC-MS/MS) results to accurately, rapidly and comprehensively achieve non-targeted screening of 34 pharmaceutical and personal care products (PPCPs) as U&U contaminants spiked in bovine and piscine muscle matrices. Three concentration groups (20, 50 and 100 ng mL-1) were intentionally designed to simulate the control and experimental groups for the discovery of marker compounds, for which multivariate and univariate analysis were adopted. In multivariate analysis, each concentration group was fully separated from other two groups in PCA and OPLS-DA plots, laying a foundation to distinguish marker compounds among groups. S-plot, permutation and variable importance in projection (VIP) in OPLS-DA were employed to screen and identify marker compounds, which were further verified by pairwise t-test and fold change judgement in univariate analysis. The results indicate that 34 PPCPs spiked in two muscle matrices were all identified as marker compounds, proving the validity and practicability of this novel metabolomics-based non-targeted screening method, which will exhibit great superiority and broad application prospects, especially in face of massive PPCPs and various animal matrices in the field of food safety control. In addition, the limits of detection (LODs) for 34 PPCPs were calculated to be 0.2 ~ 2.6 µg kg-1 and 0.3 ~ 2.1 µg kg-1 in bovine and piscine muscle matrices, respectively.

Formalin is extensively used by traders to preserve various food items like fish and mushrooms, but it has serious health hazards. Detection of formalin content in foods is a challenging problem and in the proposed work, an electrochemical sensor based on a molecular imprinted polymer of acrylonitrile over graphite platform (MiPAN@GP electrode) is pioneered for the recognition of formalin (FAL). The synthesized MiPAN@GP electrode material was characterized with Fourier transform infra-red (FTIR) spectroscope, UV-visible (UV-vis) spectroscope, and scanning electron microscope (SEM). The analytical performance of the electrode was evaluated by a three electrode system using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). A wide linear range from 10 μM to 1000 μM with a limit of detection of 0.63 μM was obtained. The MiPAN@GP sensor exhibited various advantages, such as low cost, high repeatability, high reproducibility, long term stability, and good selectivity. The practical applicability of the MiPAN@GP electrode was tested with mushroom and fish extracts which yielded satisfactory results and high accuracy (≈ 99%) when compared with the high performance liquid chromatography (HPLC) analysis results.

Ratiometric fluorescence immunoassay is known as a spectrofluorimetric variant for sensitive and quantitative analyses of biomarkers. However, there are few comparative studies between it and the traditional, single-wavelength-based immunoassay. In this work, a ratiometric fluorescence immunoassay was designed via the fluorescence resonance energy transfer (FRET) in a system comprising MnO2 nanosheets, o-phenylenediamine (OPD), and fluorescent carbon nanodots (FCNs). The MnO2 nanosheet oxidizes OPD, producing a fluorescence peak at 580 nm, while FCNs exhibit a fluorescence peak at 490 nm. Under the effect of FRET, the fluorescence at 580 nm increases significantly while the fluorescence at 490 nm is reduced. The FRET effect was confirmed by our fluorescence lifetime measurements. We optimized the experimental conditions that include solution pH, OPD concentration, and reaction time. By electrostatically coating the MnO2 nanosheets with antibody molecules and using the resultant materials as a detection probe, the ratiometric fluorescence sensing was extended to the detection of alpha fetoprotein (AFP) in human serum samples on a 96-well titer plate. Our ratiometric fluorescence immunoassay possesses a good dynamic range (from 0.14 to 130.43 pM). The detection limit was estimated to be 0.13 pM (0.009 ng/mL), which is 7.6-fold lower than that of the single-wavelength-based immunoassay. The measurement results of serum samples from healthy and patient donors are highly comparable to those measured by chemiluminescence for the same donors, demonstrating the viability for serological assays of important cancer markers.

There have been 2 spectrophotometric techniques developed, validated to find out how much folic acid there is that is simple to use, sensitive to detect, and selective. One method reduces ferric chloride in a neutral medium while simultaneously adding folic acid, and the second method is to chelate iron (II) along with 1, 10-phenanthroline (method A) on one hand and Method B depends on the interaction of the primary amino group of folic acid with the amino group of Ninhydrin in an alkaline solution, On the other hand. In Method A, red chromogens with a wavelength of 505 nm are produced, whereas, in Method B, violet chromogens with a wavelength of 575 nm are produced, and so on. Beer's law holds under ideal conditions in molar absorptivity values of 2.331104 L.mol-1 cm-1 and 6.771104 L.mol-1 cm-1, respectively, for concentration ranges of 1.0–35.0 g ml-1 and 0.5–10.0 g ml-1. Sandell's sensitivity values of 1.944 × 10–6 µg cm-2 and 1.6728 × 10–6 µg cm-2, respectively, and Sandell Technically, technique A and method B had limits of detection (LODs) of 0.198 and 0.488, respectively, and limits of quantification (LOQs) of 0.600 and 1.479, respectively. The correlation coefficients (R2) for technique A and method B were both 0.9979 and 0.9988. A and B used stability constants of 5.6192 and 5.4633 kJ.mol-1, respectively, and Gibbs free energy change (ΔG) values of −25.6071 and −24.8963, respectively, in their calculations of the free energy change (ΔG). The proposed methodologies were successfully used to evaluate folic acid in both pure and tablet form, with no influence from common excipients found in pharmaceutical formulations, demonstrating their efficacy. According to the study, there were no statistically significant differences between the precision and accuracy of the suggested procedures and those produced using the reference approach.

A simple and sensitive spectrophotometric method for the quantification of sulfite at trace level has been proposed. The method is based on the change in the intensity of the color developed on reaction of sulfite with Rhodamine-B Phenyl hydrazide (RBPH) in aqueous micellar medium. The experimental conditions such as pH, concentration of RBPH and Tween 80 have been optimized and calibration plot has been constructed. The proposed method offers a wide linearity in the concentration range 0–15 ppm of sulfite. The limit of detection and limit of quantification were found to be 0.006 and 1.5 ppm respectively, with the regression co-efficient R2 = 0.992. The proposed method has been successfully applied to measure the trace level sulfite in food samples such as tomato ketchup, jam, dry grapes, sugar and wine. Comparison of the developed method with standard protocol showed good recoveries.

Novel HPLC method was developed for enantioresolution of tyrosine kinase inhibitor drug Ibrutinib (IBT). Separation and identification of IBT enantiomers was investigated using cellulose tris (3,5-dichlorophenylcarbamate) immobilized on silica gel (Chiral-pack-IC). Good baseline enantioseparation was achieved on Chiral-pack-IC under normal-phase condition composed of n-Hexane, ethanol in a ratio of 55 and 45 (%v/v) with 0.1% Diethyl amine and 0.3% Trifluoro acetic acid. Resolution between IBT and its enantiomer was above 4. The flow rate and column oven temperature were 0.9 mL/min and 30 °C respectively. Detection was carried out at 260 nm. Injection volume optimized was 10 µL. Developed method was validated in accordance with ICH guide lines for specificity, limit of detection, limit of quantification, linearity, accuracy, precision, ruggedness and robustness.

Background: Cannabidiol (CBD) is a nonpsychoactive natural product that has been increasingly used as a promising new drug for the management of neurological conditions such as refractory epilepsy. Development of rapid and sensitive methods to quantitate CBD is essential to evaluate its pharmacokinetics in humans, particularly in children. The objective of this work was to develop and validate an ultrafast ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) method for CBD quantitation that is capable of detecting major CBD and tetrahydrocannabinol (THC) metabolites in the plasma of pediatric refractory epilepsy patients. Methods: Eight-point CBD calibration curves were prepared using 60 µL of plasma from healthy volunteers. Samples were analyzed in a Shimadzu Nexera X2 UHPLC system, which was coupled to a Sciex QTRAP 6500 mass spectrometer. Chromatography was optimized in acetonitrile (ACN)/water with a 70%–90% gradient of ACN in 2 minutes. Multiple reaction monitoring transitions of major CBD and THC metabolites were optimized in patient plasma. Results: The optimized UHPLC-MS/MS method was validated for the linear range (1–300 ng/mL) of CBD (r2 = 0.996). The limit of quantification and limit of detection were 0.26 and 0.86 ng/mL, respectively. Accuracy and precision met the acceptable validation limits. CBD recovery and matrix effects were 83.9 ± 13.9% and 117.4 ± 4.5%, respectively. The method was successfully applied to quantify CBD and detect the major CBD and THC metabolites in clinical samples. 7-COOH-CBD was the most intensely detected metabolite followed by glucuronide conjugates. Conclusions: A simple and sensitive method for rapidly monitoring CBD and identifying relevant metabolites was developed. Its applicability in samples from children treated for epilepsy was demonstrated, making it an excellent alternative for performing pharmacokinetic studies.

The main objective was to develop a wipe sampling test to measure surface contamination of the most frequently used antineoplastic drugs (ADs) in Swedish healthcare and furthermore to develop an analysis method sensitive enough to assess low levels of contamination. Two wipe sampling tests with separate sample processing methods assessing i) cyclophosphamide (CP), ifosfamide (IF), 5-fluorouracil (5-FU), etoposide (ETO), gemcitabine (GEM) and cytarabine (CYT) (Wipe Test 1), and ii) GEM, CYT and methotrexate (MTX) (Wipe Test 2), respectively were developed by optimization of absorption and extraction efficiencies using different wipe tissue materials, tissue wetting solution and extraction solvents. A fast LC-MS/MS method was developed for simultaneous detection of the studied ADs. The limit of quantification for the method was between 0.04 to 2.4 ng/wipe sample (0.10 to 6.1 pg/cm2 for an area of 400 cm2) and at 50 ng/sample the within-day precision was between 1.3-15%, and the accuracy between 102-127%. Wipe Test 1 was applied in an assessment of cleaning efficiency of five different cleaning solutions (formic acid, water, sodium hydroxide, ethanol and sodium dodecyl sulfate (SDS) for removal of ADs from surfaces made of stainless steel or plastic. For CP, IF, 5-FU, GEM and CYT 92% of the AD were removed regardless of surface and cleaning solution. In conclusion, a user-friendly assessment method to measure low levels of seven ADs in the work environment was developed and validated. Assessment of the decontamination efficiency of cleaning solutions concerning removal of ADs from stainless steel showed that efficiencies differed depending on the AD with water being the least effective cleaning agent. The results suggests that a combination of different cleaning agents including detergent and a solution with an organic component would be optimal to efficiently remove the measured ADs from surfaces in the workplace.

Organophosphorus flame retardant (OPFRs) is a new type of environmental pollutant, and the rapid and sensitive detection of OPFRs is a very important job. A new experimental phenomenon was found that TCEP, a kind of organophosphorus flame retardant, can effectively enhance the signal of the luminol-H2 O2 chemiluminescence (CL) system. Combined with the controllability of flow injection analysis, a rapid, stable, and sensitive CL method was established. The CL intensity responded linearly to the concentration of TCEP in the range 0.5 μg/L to 100 μg/L (R2 = 0.999) with a low detection limit of 33 ng/L. The relative standard deviation (R.S.D.) was 2.2 % (n= 7, c= 100 μg/L). The water samples were labeled and recycled with RSDs of 1.1 % - 5.7 % and recoveries of 88.7 % - 116.1 %. Based on this, this study established a new CL detection method for environmental pollutant TCEP.

Fluorobenzoic acids are critically important chemical tracers in hydrothermal, geothermal, leaching, and oilfield applications. Particularly in oilfield applications, these tracers are used to investigate fluid flow paths between injector wells and producer wells, providing valuable information about the enhanced oil recovery process of the oil reservoirs. The detection limit of tracers is a vital subject in field reservoir work because the amount of chemical tracer that must be injected into the injector well is directly related to the amount detected at the producer well after migration and diffusion. The popularity of fluorinated benzoic acids as the tracers is due to their non-toxicity over radioactive tracers and low detection limit, which is determined using analytical techniques. This review focuses on the improvements/developments in extraction techniques such as solid-phase extraction and determination techniques such as Gas chromatography coupled with mass spectrometry, Liquid chromatography with mass spectrometry, Isotope Dilution Gas chromatography-mass spectrometry, High-performance Liquid Chromatography, Ion chromatography coupled with electrospray mass spectrometry, etc. for the analysis of fluorinated benzoic acids to achieve the lowest possible limit of concentration. This article is protected by copyright. All rights reserved.

BACKGROUND In this study, development and validation of a simple, miniaturised and, environmentally friendly carrier mediated three phase hollow fibre liquid phase micro-extraction (HFLPME) technique was investigated for the enrichment of tetracycline residues in honey samples. The extracts were analyzed using UV/Vis spectrophotometry and the LC-Q-TOF/MS. Parameters affecting the extraction efficiency of HFLPME such as pH of the donor and acceptor solutions, salt addition, agitation speed and extraction time were optimized. RESULTS The calibration curves showed good linearity, in the range of 1-100 μg kg-1 with correlation coefficients ranging between 0.9943 and 0.9992, under the optimized conditions. Recoveries of blank honey samples at three spiking levels (1, 10 and 20 μg kg-1 ) ranged from 81.2% to 107.5%. RSDs for the precision of the method were less than 15.0%. LODs and LOQs were in the ranges of 0.0861 to 0.2628 μg kg-1 and 0.2610 to 0.7964 μg kg-1 , respectively. Finally, the proposed method was successfully applied in the extraction of five tetracyclines from honey samples. Doxycycline residue detected in one of the commercial honey samples was below the limit of quantification. CONCLUSION Due to the advantages offered by HFLPME, this method can be employed as an alternative to conventional extraction techniques for the clean-up and pre-concentration of antibiotics in complex matrices including food samples. This article is protected by copyright. All rights reserved.

In this work, an innovative colorimetric assay method for the determination of carcinoembryonic antigen (CEA) is developed with aptamer probes utilized as recognition element. DNA hybridization chain reaction (HCR) is used as signal amplification technique, and peroxidase-mimicking hemin/G-quadruplex-assisted catalytic oxidation of 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) is deployed as signal reporting mechanism. The detection principle was firstly verified by using gel electrophoresis analysis and absorbance measurements. After condition optimization, a detection limit was theoretically determined as 24.8 ng/mL. Furthermore, the method exhibited good selectivity and satisfactory recovery rates (92.2~108.6%) in serum samples. Moreover, the sensing scheme is easily extended for the detection of other analytes via similar target-aptamer recognition principle. To sum up, this is an enzyme- and label-free, cost-effective yet signal-amplifiable assay scheme for the determination of tumor markers with promising simplicity and selectivity, practical utility, and potential universality. This article is protected by copyright. All rights reserved.

Fabric-phase sorptive extraction (FPSE) coats organic–inorganic hybrid sorbent materials onto flexible and hydrophilic fabrics through sol–gel sorbent-coating technology. Herein, we explored four different coating chemistries, including those of nonpolar sol–gel poly(dimethylsiloxane), medium polar sol–gel poly(tetrahydrofuran), and polar sol–gel poly(ethylene glycol) (PEG)–block-poly(propylene glycol)–PEG, and sol–gel PEG. Results showed that PEG had the best extraction recoveries for the majority of the analytes. Subsequently, strongly polar sol–gels were prepared using PEG as precursor and FPSE medium. FPSE was then combined with a cut solid-phase extraction column and immobilised with magnetic-stirring beads so that FPSE could be automatically stirred magnetically throughout the entire extraction process. The developed method based on ultra-high-performance liquid chromatography–tandem mass spectrometry showed good linearity within the concentration range of 5–200 ng/mL. Under the optimum experimental conditions, limits of detection for 48 pesticides were obtained within the range of 0.014–6.280 ng/mL. Thereafter, the new method was applied to tomato, cucumber, and cabbage samples. Recoveries ranged from 71.4 to 99.8% at three concentration levels. The various parameters of this experimental method were systematically investigated and optimised to improve its sensitivity and prove its feasibility in vegetables. Overall, our results demonstrated that the method was simple, sensitive, efficient, and rapid. Furthermore, FPSE fibre cloth showed great potential for commercial exploitation because of its reusability.

Since inulin utilization as a sugar or fat replacer, texture modifier, and emulsifier is increasing in the food industry, there is a need for its determination for food control and labeling. This study reports the development and validation of an advanced high-performance liquid chromatographic method with evaporative light-scattering detection (HPLC-ELSD) method for inulin quantification, with optimized extraction conditions (1:10 w/v solid-to-solvent ratio, 1 h/80 °C in a water bath continued with 30 min ultrasonication for the extraction step, and precipitation during the night with four volumes of acetone). The rapid HPLC-ELSD analysis (16 min) has been performed by isocratic elution with water as a mobile phase and optimized detector parameters (temperature of evaporator 80 °C, temperature of nebuliser 80 °C, gas flow rate 1.3 standard liters per minute, detector gain 1). The method was validated in terms of limits of detection and quantification, intra- and inter-day precision and accuracy, and recovery. The proposed method was carried out using a cation exchange (Ag +) column for the first time for the inulin determination, avoiding the hydrolysis step in order to simplify and accelerate the quantification.

Enantioseparation of three β-blockers, i.e., atenolol, metoprolol and propranolol, was studied on amylose tris(3-chloro-5-methylphenylcarbamate) immobilized chiral stationary phase using supercritical fluid chromatography (SFC). The effect of organic modifiers (methanol, isopropanol and their mixture), column temperature and back pressure on chiral separation of β-blockers was evaluated. Optimum chromatographic separation with respect to resolution, retention, and analysis time was achieved using a mixture of CO2 and 0.1% isopropyl amine in isopropanol: methanol (50:50, V/V), in 75:25 (V/V) ratio. Under the optimized conditions, the resolution factors (Rs) and separation factors (α) were greater than 3.0 and 1.5, respectively. Further, with increase in temperature (25–45 °C) and pressure (100–150 bars) there was corresponding decrease in retention factors (k), α and Rs. However, a reverse trend (α and Rs) was observed for atenolol with increase in temperature. The thermodynamic data from van't Hoff plots revealed that the enantioseparation was enthalpy driven for metoprolol and propranolol while entropy driven for atenolol. To understand the mechanism of chiral recognition and the elution behavior of the enantiomers, molecular docking studies were performed. The binding energies obtained from simulation studies were in good agreement with the elution order found experimentally and also with the free energy values. The method was validated in the concentration range of 0.5–10 μg/mL for all the enantiomers. The limit of detection and limit of quantitation ranged from 0.126 to 0.137 μg/mL and 0.376–0.414 μg/mL, respectively. The method was used successfully to analyze these drugs in pharmaceutical preparations., Graphical abstract Image 1, Highlights • Simultaneous enantioseparation of three β-blockers in a single analysis using chiral SFC • Separation efficiency was mainly dependent on the nature and composition of mobile phase • van't Hoff plots revealed enthalpy driven process for metoprolol and propranolol and entropy driven for atenolol • Binding energies from molecular docking study were in good agreement with the elution order • The results suggested hydrogen bonding and hydrophobic interactions, as the dominant interaction modes.

Salmonella is a foodborne pathogen that has contributed to numerous food safety accidents worldwide, making it necessary to detect contamination at an early stage. A pair of specific primers based on the invA gene of Salmonella was designed for PCR. Target double-stranded DNA (dsDNA) from PCR was purified and denatured at high temperature to obtain target single-stranded DNA (ssDNA). Two carboxyfluorescein-labeled hairpin probes (H1-FAM and H2-FAM) were designed with complementary portions to the ssDNA sequence so that binding could trigger H1-FAM and H2-FAM hybridization chain reaction (HCR) to produce a long dsDNA complex. In this study, graphene oxide (GO) was used in the development of a homogeneous fluorescence detection platform for Salmonella. Using this HCR-GO assay platform, Salmonella detection was completed in 3.5 h. Salmonella was reliably and specifically detected with a limit of detection (LOD) of 4.2 × 101 cfu/mL in pure culture. Moreover, this new HCR-GO assay platform was successfully applied to the detection of Salmonella in artificially contaminated milk with a LOD of 4.2 × 102 cfu/mL.

Eight new generation amide insecticide residues analysis by multiwalled carbon nanotubes (MWCNs) cleanup, combined with QuEChERS and ultrahigh performance liquid chromatography tandem mass spectrometry has been developed and successfully applied in complex matrix such as orange, celery, onion, litchi, mango, shallot, chives, avocado, garlic. The matric effect of MWCNs is optimized and compared with ordinary cleanup materials. The results show that the performance of MWCNs is fine and effectively reduce matrix interference. Through chemical structure skeletons analyzed, chlorantraniliprole, bromoantraniliprole, and cyantraniliprole can cause same product ions of m/z 286.0 or 177.1 in the ESI+ mode, then tetrachlorantraniliprole and cyclaniliprole can produce collective ions of m/z 146.9 in the ESI− mode. The coefficients (R2) were greater than 0.9990, the limit of quantification ranges from 0.03 to 0.80 μg/kg, the recovery rate ranges from 71.2 to 120%, and the relative standard deviation (RSD) ranges from 3.8 to 9.4%. The method is fast, simple, sensitive, and suitable for the rapid determination of amide pesticides in complex matrix agricultural food.

Enniatins (ENNs) and beauvericin (BEA), known as emerging mycotoxins, are the toxic secondary metabolites produced by various Fusarium species. Most grain and grain-based products are contaminated with ENNs and BEA. Animals have been exposed to ENNs and BEA primarily due to consumption of cereal grains and cereal by-products. ENNs and BEA have been detected in animal-derived food and human breast milk, and they pose significant threats to public health. Therefore, more contamination data are urgently needed for the risk assessment of ENNs and BEA present in animal-derived food. To ensure the quality of animal-derived food, a method has been developed for the simultaneous detection of five emerging mycotoxins (viz. enniatin B, enniatin B1, enniatin A, enniatin A1, and beauvericin) in eggs by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) coupled with cold-induced liquid-liquid extraction (CI-LLE) and dispersive solid phase extraction (DSPE). The main factors governing the response, recovery, and sensitivity of the method, such as the type of extraction solvent, the temperature and duration of cold treatment in CI-LLE, the type and dosages of adsorbents, and apparatus conditions and the type of mobile phase used, were optimized during sample pretreatment and instrument analysis. The mycotoxin residues in eggs were extracted using 20 mL acetonitrile-water-acetic acid (79∶20∶1, v/v/v) mixture for 20 min by the vortex shock method. After mixing, the mixture was frozen for 30 min in a freezer at -40 ℃ and centrifuged for 10 min at 10000 r/min. A 2 mL aliquot of the upper acetonitrile layer was purified by using 70 mg of C18 adsorbents. After whirling, the mixtures were centrifuged at 10000 r/min for 5 min. The purified solution was then concentrated to nearly dry in nitrogen atmosphere at 40 ℃. The residues were dissolved in 1.0 mL 80%(v/v) acetonitrile aqueous solution. The target analytes were separated on an ACQUITY UPLC BEH C18 chromatographic column (100 mm×2.1 mm, 1.7 μm) at a column temperature of 40 ℃, with a flow rate of 0.3 mL/min. The injection volume was 5 μL, and gradient elution was conducted using acetonitrile and 5 mmol/L ammonium formate solution as the mobile phases. Multiple reactions monitoring (MRM) was conducted in the positive electrospray ionization (ESI +) mode. The isotope internal standard method was used for quantification of BEA, and the matrix-matched external standard method was used for quantification of four ENNs. The results of the optimized method showed that the five analytes were completely separated by using the above-mentioned chromatographic column. Good linear relationships were obtained for the five mycotoxins in the concentration range of 0.1-50.0 μg/L; the correlation coefficient (r2) ranged from 0.9983 to 0.9997. The limits of detection (LODs) ranged from 0.05 to 0.15 μg/kg, while the limits of quantification (LOQs) ranged from 0.20 to 0.50 μg/kg. Accuracy and precision experiments were conducted by spiking egg samples with known amounts of analytes at three concentration levels (0.5, 5.0, and 25.0 μg/kg, in compliance with the current legislation) with six replicates. The average recoveries of the five analytes ranged from 81.1% to 106%, and the relative standard deviations (RSDs) were between 0.27% and 9.79%. The matrix effects of the analytes were between 2.70% and 45.1% in egg samples after pretreatment by CI-LLE coupled with DSPE. The developed method was applied to the determination of five mycotoxins in rural eggs and commercial eggs. BEA was detected in most rural egg samples, with detection rates of 30.4%. None of the four ENN residues were detected. Therefore, we can conclude that the method described herein has the advantages of sensitivity, stabilization, accuracy, good recovery, and easy operation, and is suitable for the simultaneous and rapid determination of BEA and ENN residues in eggs.

In this study, a capillary electrophoresis-based online immobilized acetylcholinesterase (AChE) microreactor was developed for the determination of organophosphorus pesticide (OPs) residues in six fruit and vegetable juice samples. AChE was immobilized on the inner wall at the inlet of the capillary via polydopamine (PDA) coating. The immobilized AChE activity and other kinetic parameters were evaluated by measuring the peak area of the product (thiocholine). The value of Michaelis-Menten constant (Km) was determined to be 3.11 mM, and the half-maximal inhibitory concentration (IC50) and inhibition constant (Ki) of tacrine on immobilized AChE were measured to be 0.46 μM and 0.27 μM, respectively. The activity of the immobilized AChE remained more than 85.0% of its initial immobilized enzyme activity after 30 runs. Then, the developed strategy was successfully applied to detect the acephate in six fruit and vegetable juice samples (apple, pear, peach, tomato, cucumber and lettuce juice) with a limit of detection (LOD) of 11.0 ng/mL. Results show that the recovery of spiked samples are in the range of 86.0-96.0% with RSD of less than 5.7%. Therefore, the proposed method is capable of achieving rapid analysis of acephate with simple operation when there are no other types of OPs in the real samples.

Rapid and credible detection of pathogens is essential to prevent and control outbreaks of foodborne diseases. In this study, a poly-l-lysine-functionalized magnetic beads (PLL-MB) strategy combined with a PCR assay was established to detect Staphylococcus aureus. We also detected Escherichia coli O157:H7 to further verify the strategy for gram-negative bacteria detection. Poly-l-lysine has strong positive charges because of its amino groups, which can conjugate with the carboxyl of carboxyl magnetic beads. Furthermore, it can be used to combine with bacteria through electrostatic adsorption. Under optimum conditions, the developed PLL-MB complexes showed 90% capture efficiency in phosphate-buffered saline and 85% capture efficiency in milk for S. aureus detection. The limit of detection of the PLL-MB-PCR assay was 102 cfu/mL (1.8 × 102 cfu/mL for S. aureus and 7 × 102 cfu/mL for E. coli O157:H7) in phosphate-buffered saline and milk samples. The whole assay can be performed within 4 h. The proposed strategy showed a lower limit of detection when compared with the conventional PCR assay without enrichment. In addition, this method exhibited the advantages of a high-efficient, cost-efficient, and simple operation, indicating its potential applications in foodborne pathogen detection.

Carbamate pesticides are a class of synthetic pesticides having wide antimicrobial spectrum, good insecticidal efficacy, and a short residual period. These pesticides are used in agriculture, forestry, and animal husbandry. Their widespread use in the last two decades has led to the existence of drug residues in the environment, which are transferred to food, thereby raising concerns regarding the potential threat to human health. Rapid and accurate detection of carbamate pesticide residues in food is of great significance for food safety, and this requires pretreatment to purify the target components and maximize the accuracy and precision of the analysis. A rapid and accurate analytical method based on online solid phase extraction/purification-high performance liquid chromatography-tandem mass spectrometry (online SPE-HPLC-MS/MS) was established for the determination of eight carbamate pesticides in tomato, rice, and cabbage. About 5.0 g of tomato (without water), 2.0 g of cabbage, and 2.0 g of rice (mixed with 3 mL of water) were vortexed at 1000 r/min for 1 min. After adding 2 g of sodium chloride and 10 mL of acetonitrile containing 0.5% (v/v) formic acid, the samples were extracted and centrifuged. The supernatants were combined after the samples were extracted again. The reconstituted solutions were then purified on a CAPCELL PAK C18 column (50 mm×2.0 mm, 15 μm). When the volume ratio of 0.1% (v/v) formic acid aqueous solution and acetonitrile (used as the mobile phases) was 90∶10 and 35∶65, the eight carbamate pesticides could be completely adsorbed and eluted. The carbamate pesticides were separated on an ACQUITY UPLC CSH C18 column (100 mm×2.1 mm, 1.7 μm) under gradient elution and analyzed in the multiple reaction monitoring (MRM) mode with positive electrospray ionization (ESI+). Under the optimum conditions, the calibration curves of the eight carbamate pesticide residues showed good linearity (r>0.995) within their respective linear ranges. The limits of quantification (LOQs) and limits of detection (LODs) were in the range of 0.05-1.0 ng/mL (S/N=10) and 0.01-0.3 ng/mL (S/N=3). The recoveries were in the range of 73.76%-112.32% at three spiked levels (2, 10, and 20 ng/mL), with relative standard deviations of 1.28%-13.14% (n=6). The online purification method showed better enrichment and purification ability for the target substances than did the offline purification method and greatly improved the pretreatment efficiency. The loading and purification could be completed within 12 min. The developed method has the advantages of high recovery rate, good reproducibility, accuracy, rapidness, sensitivity, and environment friendliness. It can be used for the determination of the eight carbamate pesticides in plant foods, such as tomato, rice, and cabbage.