Fast Sample Preparation Procedure Research Articles

Improved procedure for square-wave voltammetric sensing of fenhexamid residues on blueberries peel surface at the anodically pretreated boron-doped diamond electrode

BackgroundFungicide fenhexamid (FH) has a high residual concentration on fruits and vegetables, thus, it is of high importance to monitor the level of FH residues on foodstuff samples. So far, the assay of FH residues in selected foodstuff samples has been conducted by electroanalytical methods on sp2 carbon-based electrodes that are well-known to be susceptible to severe fouling of the electrodes surfaces during electrochemical measurements. As an alternative, sp3 carbon-based electrode such as boron-doped diamond (BDD) can be used in the analysis of FH residues retained on the peel surface of foodstuff (blueberries) sample. ResultsIn situ anodic pretreatment of the BDDE surface was found to be the most successful strategy to remediate the passivated BDDE surface by FH oxidation (by)products, and the best validation parameters, i.e., the widest linear range (3.0–100.0 μmol L−1), the highest sensitivity (0.0265 μA L μmol−1) and the lowest limit of detection (0.821 μmol L−1), were achieved on the anodically pretreated BDDE (APT–BDDE) in a Britton-Robinson buffer, pH 2.0, using square-wave voltammetry (SWV). The assay of FH residues retained on blueberries peel surface was performed on the APT–BDDE using SWV, and the obtained concentration of FH residues of 6.152 μmol L−1 (1.859 mg kg−1) was found to be below the maximum residue value fixed for blueberries by the European Union regulations (20 mg kg−1). Significance and noveltyIn this work, a protocol based on a very easy and fast foodstuff sample preparation procedure combined with the straightforward pretreatment approach of the BDDE surface was elaborated for the first time for the monitoring of the level of FH residues retained on the peel surface of blueberries samples. The presented reliable, cost-effective, and easy-to-use protocol could find its application as a rapid screening method for the control of food safety.

Air-assisted liquid-liquid microextraction of total 3-monochloropropane-1,2-diol from refined edible oils based on a natural deep eutectic solvent and its determination by gas chromatography-mass spectrometry

In this paper, a fast, sensitive, and selective sample preparation procedure was presented for the determination of 3-monochloropropane-1,2-diol (3-MCPD) in refined edible oils using gas chromatography-mass spectrometry. In this method, firstly, the sample lipids and analyte fatty esters are saponified by sodium hydroxide under sonication. After that the analyte was derivatized using phenylboronic acid (as the derivatization agent) and the obtained derivative was extracted during an air-assisted liquid-liquid microextraction procedure (AALLME). Six different deep eutectic solvents (DESs) were prepared as the extraction solvents and the most effective extraction for 3-MCPD was obtained in the presence of a natural DES (NDES) consisting of choline chloride (ChCl)-acetic acid (AcOH). Important variables such as sodium hydroxide concentration and volume, sonication time, temperature, extraction solvent type and volume, and phenylboronic acid concentration and volume have been optimized. Using the optimum conditions, broad linear range (0.88-1000 ng g–1), suitable coefficient of determination (0.995), and low limits of detection (0.26 ng g–1) and quantification (0.88 ng g−1) were obtained. Relative standard deviations for intra– (n=8) and inter-day (n=6) precisions at a concentration of 5 ng g−1 were 2.6 and 3.2%, respectively. The developed method has been successfully applied to 3-MCPD determination in refined edible oil samples including sunflower, corn, and canola oils.

Visualization of materials using the confocal laser scanning microscopy technique.

The development of materials science always benefits from advanced characterizations. Currently, imaging techniques are of great technological importance in both fundamental and applied research on materials. In comparison to conventional visualization methods, confocal laser scanning microscopy (CLSM) is non-invasive, with macroscale and high-contrast scanning, a simple and fast sample preparation procedure as well as easy operation. In addition, CLSM allows rapid acquisition of longitudinal and cross-sectional images at any position in a material. Therefore, the CLSM-based visualization technique could provide direct and model-independent insight into material characterizations. This review summarizes the recent applications of CLSM in materials science. The current CLSM approaches for the visualization of surface structures, internal structures, spatial structures and reaction processes are discussed in detail. Finally, we provide our thoughts and predictions on the future development of CLSM in materials science. The purpose of this review is to guide researchers to build a suitable CLSM approach for material characterizations, and to open viable opportunities and inspirations for the development of new strategies aiming at the preparation of advanced materials. We hope that this review will be useful for a wide range of research communities of materials science, chemistry, and engineering.

Simplified Method of Multi-Elemental Analysis of Dialyzable Fraction of Tea Infusions by FAAS and ICP OES

A fast and straightforward sample preparation procedure of the dialyzable fraction of infusions of teas prior to their analysis on Al, Ba, Ca, Cu, Fe, Mg, Mn, Ni, Sr, and Zn contents by flame atomic absorption spectrometry (FAAS) and inductively coupled plasma optical emission spectrometry (ICP OES) was developed and validated. The proposed methodology was based on acidification with HNO3 only and demonstrated good analytical performance, i.e., precision (0.80–5.0%), accuracy (< 5%), recoveries of elements (97.4–105%), and their detection limits (0.075–1.1 μg L−1) along with linearity of calibration curves in the whole studied concentration ranges. Applicability of the evaluated procedure, being a useful alternative to time-consuming wet digestions, was tested by determining bioaccessibility of elements in 20 infusions of black (BT) and green (GT) teas as assessed with the aid of in vitro gastrointestinal digestion. Average contributions of bioaccessible fractions (%) of studied metals were as follows: 1.18 (Al)–40.7% (Ca) and 4.65% (Al)–46.3% (Ca) for BTs and GTs, respectively. Drinking daily four cups (1 L) of tea, recommended dietary intakes (RDIs) of Ca, Cu, Fe, Mg, and Zn were covered to a small degree (< 1.5%). Only bioaccessibility of Mn highly contributed to RDI for this metal. According to provisional tolerable weekly intakes (PTWIs) for toxic elements such as Al and Ni, consumption of both types of teas should not represent any health risk. Additionally, analysis of variance of results clearly indicated that BTs and GTs were mostly differentiated due to concentrations of the bioaccessible fraction of Al, Ba, Cu, and Ni.

Determination of selected dichloroanilines and phthalates in lyophilised mussels samples with ultra-high performance liquid chromatography-tandem mass spectrometry after QuEChERS clean-up

ABSTRACT Mussels, a marine filter organism, constitute a food product and an established sentinel organism for marine pollution. An analytical method following a QuEChERS extraction and clean-up protocol has been developed for the determination of phthalic acid esters (PAE), including di-n-octyl phthalate (DnOP), di-(2-ethyl hexyl) phthalate (DEHP), butyl benzyl phthalate (BBP), di-methyl phthalate (DMP) and di-n-butyl phthalate (DnBP), as well as 3,4-dichloroaniline and 3,5-dichloroaniline in lyophilised mussels samples. A gradient elution program starting from 40% A (methanol-0.1% formic acid) – 60% B (H2O-0.1% formic acid) up to 100% A was applied, with a total duration of 15 min, at a flow rate of 200 μL min−1 using a 1.8 μm particle size C18 analytical column. All target analytes were detected with a triple quadrupole MS, using electrospray ionisation (ESI) in positive ionisation mode, in SRM mode under optimised conditions. Sample preparation consisted of lyophilisation of the mussels sample and grinding, followed by a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) protocol. Among the different dispersants evaluated for sample clean-up effectiveness, primary secondary amine (PSA) was found to be the most efficient. Results indicated good chromatographic separation, fast sample preparation procedure, low LODs and LOQs, good trueness expressed as recovery and good precision as evaluated by RSD. In the mussels samples examined DEHP was the most abundant PAE, reaching a maximal concentration of 280 μg/kg of lyophilised weight whereas the levels of DnBP were at approximately 36% of the legal migration limit in foods determined by the EU.

Determination of polybrominated biphenyls in environmental water samples by ultrasound-assisted dispersive liquid-liquid microextraction followed by high-performance liquid chromatography

Dispersive liquid-liquid microextraction (DLLME) is an extraordinarily fast and effective sample preparation procedure. In this work, a simple, rapid, and sensitive method using ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) combined with high-performance liquid chromatography (HPLC) has been developed for rapid determination polybrominated biphenyls (PBBs) in real water samples. The key parameters affecting the extraction efficiency including the extractant, dispersant, the volumes of extractant and dispersant, and ultrasound time were optimized, and further validated by orthogonal array design (OAD), a L16 (44) matrix was applied for the identification of optimized extraction parameters, and the optimized method was successfully applied to the analysis of environmental water sample. The results showed good linearity (correlation coefficients > 0.9942), low limits of detection (0.11–0.12 μg L−1), wide linear ranges (0.5–1000 μg L−1), and acceptable repeatability (relative standard deviation, RSD < 5.2% for intra-day, RSD <6.3% for inter-day). Moreover, the method is further applied to the analysis of four PBBs in real samples with good recoveries (75.8%–105%) and satisfactory precisions (RSD < 6.5%). The optimized conditions provided enrichment factors (EFs) for PBBs of 211–245.

Investigation of a rapid infrared heating assisted mineralization of soybean matrices for trace element analysis

A fast sample preparation procedure based on use of infrared (IR) assisted heating for mineralization of soybean derived samples has been developed for their subsequent multielement analysis by inductively coupled plasma optical emission spectrometry (ICP-OES) and flame atomic absorption spectrometry (FAAS). A cold finger was examined for refluxing of acid vapors to determine its impact on efficiency and economy of digestion. The optimized procedure, based on 1 g subsamples, 8 mL of HNO3 (65% w/w) and exposure of the mixture to a 500 W IR source for 5 min without refluxing, permitted accurate determination of all analytes in NIST SRM 1568b (rice flour). Detection limits using ICP-OES were (µg/kg) 97, 1.0, 39, 185, 0.47 and 1200 for Ca, Cu, Fe, K, Mn and P, respectively, and 18 for Zn by FAAS. The IR-assisted digestion approach provided a low cost, easy to use system having great potential for implementation in routine analysis of trace elements in soybean and similar matrices.

A fully automated simultaneous single-stage separation of Sr, Pb, and Nd using DGA Resin for the isotopic analysis of marine sediments.

A novel, fast and reliable sample preparation procedure for the simultaneous separation of Sr, Pb, and Nd has been developed for subsequent isotope ratio analysis of sediment digests. The method applying a fully automated, low-pressure chromatographic system separates all three analytes in a single-stage extraction step using self-packed columns filled with DGA Resin. The fully automated set-up allows the unattended processing of three isotopic systems from one sediment digest every 2h, offering high sample throughput of up to 12 samples per day and reducing substantially laboratory manpower as compared to conventional manual methods. The developed separation method was validated using the marine sediment GBW-07313 as matrix-matched certified reference material and combines quantitative recoveries (>90% for Sr, >93% for Pb, and >91% for Nd) with low procedural blank levels following the sample separation (0.07μgL-1 Sr, 0.03μgL-1 Pb, and 0.57μgL-1 Nd). The average δ values for Sr, Pb, and Nd of the separated reference standards were within the certified ranges (δ (87Sr/86Sr)NIST SRM 987 of -0.05(28)‰, δ(208Pb/206Pb)NIST SRM 981 of -0.21(14)‰, and δ(143Nd/144Nd)JNdi-1 of 0.00(7)‰). The DGA Resin proved to be reusable for the separation of >10 sediment digests with no significant carry-over or memory effects, as well as no significant on-column fractionation of Sr, Pb, and Nd isotope ratios. Additional spike experiments of NIST SRM 987 with Pb, NIST SRM 981 with Sr, and JNdi-1 with Ce revealed no significant impact on the measured isotopic ratios, caused by potential small analyte peak overlaps during the separation of Sr and Pb, as well as Ce and Nd.

Feasibility of a Fast and Green Chemistry Sample Preparation Procedure for the Determination of K and Na in Renewable Oilseed Sources by Flame Atomic Emission Spectrometry

Feasibility of a Fast and Green Chemistry Sample Preparation Procedure for the Determination of K and Na in Renewable Oilseed Sources by Flame Atomic Emission Spectrometry

Changes in the expression of N- and O-glycopeptides in patients with colorectal cancer and hepatocellular carcinoma quantified by full-MS scan FT-ICR and multiple reaction monitoring

Alternations in the glycosylation of proteins have been described in connection with several cancers, including hepatocellular carcinoma (HCC) and colorectal cancer. Analytical tools, which use combination of liquid chromatography and mass spectrometry, allow precise and sensitive description of these changes. In this study, we use MRM and FT-ICR operating in full-MS scan, to determine ratios of intensities of specific glycopeptides in HCC, colorectal cancer, and liver metastasis of colorectal cancer. Haptoglobin, hemopexin and complement factor H were detected after albumin depletion and the N-linked glycopeptides with fucosylated glycans were compared with their non-fucosylated forms. In addition, sialylated forms of an O-linked glycopeptide of hemopexin were quantified in the same samples. We observe significant increase in fucosylation of all three proteins and increase in bi-sialylated O-glycopeptide of hemopexin in HCC of hepatitis C viral (HCV) etiology by both LC-MS methods. The results of the MRM and full-MS scan FT-ICR analyses provide comparable quantitative readouts in spite of chromatographic, mass spectrometric and data analysis differences. Our results suggest that both workflows allow adequate relative quantification of glycopeptides and suggest that HCC of HCV etiology differs in glycosylation from colorectal cancer and liver metastasis of colorectal cancer. SignificanceThe article compares N- and O-glycosylation of several serum proteins in different diseases by a fast and easy sample preparation procedure in combination with high resolution Fourier transform ion cyclotron resonance mass spectrometry. The results show successful glycopeptides relative quantification in a complex peptide mixture by the high resolution instrument and the detection of glycan differences between the different types of cancer diseases. The presented method is comparable to conventional targeted MRM approach but allows additional curation of the data.

Contamination risk of stable isotope samples during milling.

Isotope analysis of wood is an important tool in dendrochronology and ecophysiology. Prior to mass spectrometry analysis, wood must be homogenized, and a convenient method involves a ball mill capable of milling samples directly in sample tubes. However, sample-tube plastic can contaminate wood during milling, which could lead to biological misinterpretations. We tested possible contamination of whole wood and cellulose samples during ball-mill homogenization for carbon and oxygen isotope measurements. We used a multi-factorial design with two/three steel milling balls, two sample amounts (10mg, 40mg), and two milling times (5min, 10min). We further analyzed abrasion by milling empty tubes, and measured the isotope ratios of pure contaminants. A strong risk exists for carbon isotope bias through plastic contamination: the δ(13) C value of polypropylene deviated from the control by -6.77‰. Small fibers from PTFE filter bags used during cellulose extraction also present a risk as the δ(13) C value of this plastic deviated by -5.02‰. Low sample amounts (10mg) showed highest contamination due to increased abrasion during milling (-1.34‰), which is further concentrated by cellulose extraction (-3.38‰). Oxygen isotope measurements were unaffected. A ball mill can be used to homogenize samples within test tubes prior to oxygen isotope analysis, but not prior to carbon or radiocarbon isotope analysis. There is still a need for a fast, simple and contamination-free sample preparation procedure. Copyright © 2016 John Wiley & Sons, Ltd.

Liquid chromatography mass spectrometry determination of perfluoroalkyl acids in environmental solid extracts after phospholipid removal and on-line turbulent flow chromatography purification

An on-line TFC (Turbulent Flow Chromatography) clean up procedures coupled with UHPLC–MS/MS (Ultra High Performance Liquid Chromatography Mass Spectrometry) multi-residue method was developed for the simultaneous determination of 8 perfluroalkyl carboxylic acids (PFCA, from 5 to 12 carbon atoms) and 3 perfluoroalkyl sulfonic acids (PFSA, from 4 to 8 carbon atoms) in environmental solid matrices. Fast sample preparation procedure was based on a sonication-assisted extraction with acetonitrile. Phospholipids in biological samples were fully removed by an off-line SPE purification before injection, using HybridSPE® Phospholipid Ultra cartridges.The development of the on-line TFC clean-up procedure regarded the choice of the stationary phase, the optimization of the mobile phase composition, flow rate and injected volume.The validation of the optimized method included the evaluation of matrix effects, accuracy and reproducibility. Signal suppression in the analysis of fortified extracts ranged from 1 to 60%, and this problem was overcome by using isotopic dilution. Since no certified reference materials were available for PFAS in these matrices, accuracy was evaluated by recoveries on spiked clam samples which were 98–133% for PFCAs and 40–60% for PFSAs. MLDs and MLQs ranged from 0.03 to 0.3ngg−1 wet weight and from 0.1 to 0.9ngg−1 wet weight respectively. Repeatability (intra-day precision) and reproducibility (inter-day precision) showed RSD from 3 to 13% and from 4 to 27% respectively. Validated on-line TFC/UHPLC–MS/MS method has been applied for the determination of perfluoroalkyl acids in different solid matrices (sediment, fish, bivalves and bird yolk).

Automated Agitation-Assisted Demulsification Dispersive Liquid–Liquid Microextraction

Dispersive liquid-liquid microextraction (DLLME) is an extremely fast and efficient sample preparation procedure. For its capability and applicability to be fully exploited, full automation of its operations seamlessly integrated with analysis is necessary. In this work, for the first time, fully automated agitation-assisted demulsification (AAD)-DLLME integrated with gas chromatography/mass spectrometry was developed for the convenient and efficient determination of polycyclic aromatic hydrocarbons in environmental water samples. The use of a commercially available multipurpose autosampler equipped with two microsyringes of different capacities allowed elimination or significant reduction of manpower, labor, and time with the large-volume microsyringe used for liquid transfers and the small-volume microsyringe for extract collection and injection for analysis. Apart from enhancing accessibility of DLLME, the procedure was characterized by the application of agitation after extraction to break up the emulsion (that otherwise would need centrifugation or a demulsification solvent), further improving overall operational efficiency and flexibility. Additionally, the application of low-density solvent as extractant facilitated the easy collection of extract as the upper layer over water. Some parameters affecting the automated AAD-DDLME procedure were investigated. Under the optimized conditions, the procedure provided good linearity (ranging from a minimum of 0.1-0.5 μg/L to a maximum of 50 μg/L), low limits of detection (0.010-0.058 μg/L), and good repeatability of the extractions (relative standard deviations, below 5.3%, n = 6). The proposed method was applied to analyze PAHs in real river water samples.

High-performance liquid chromatography–high-resolution time-of-flight mass spectrometry in the identification and determination of penicillin and tetracycline group antibiotics in food

A method of the identification and determination of 27 antibiotics of penicillin (15) and tetracycline (12) groups in food using high-resolution time-of-flight mass spectrometry combined with high-performance liquid chromatography and a simple and fast sample preparation procedure have been developed. The analytical range for penicillins is 3 (50)–300 (1000) μg/kg and for tetracyclines, 0.3 (1.5)–100 (200) μg/kg. A scheme of the identification and determination of antibiotics using the standard addition method has been proposed. The relative standard deviation of the results of analysis does not exceed 10%. The time of sample screening is 30–40 min, the time of the determination of the detected antibiotics is 2–3 h.

Rapid immunochemical analysis of the sulfonamide-sugar conjugated fraction of antibiotic contaminated honey samples

A rapid high-throughput immunochemical screening (HtiS) procedure for the analysis of the sulfonamide (SA)-sugar conjugated fraction of antibiotic contaminated honey samples has been developed. Studies performed with this matrix have indicated that sulfonamide antibiotics are conjugated to sugars rapidly and quantitatively, providing samples with very low SA immunoreactivity. Therefore, sulfonamides must be first released before the analysis, and for this purpose, a simple and fast sample preparation procedure has been established consisting of hydrolyzing the sample for 5min, adjusting the pH and buffering the sample prior to the immunochemical analysis. Under these conditions, honey samples could be directly analyzed without any additional sample treatment, other than dilution. Recovery values of the whole analytical procedure were greater than 85%. The analysis of the same samples without the hydrolysis provided recovery values below 5%. Selectivity studies performed in hydrolyzed honey samples revealed that nine relevant sulfonamide antibiotics can be detected with limit of detection (LOD) values below the action limits established by some EU countries (Belgium, 20μgkg−1, United Kingdom or Switzerland, 50μgkg−1).

Simple and Fast Sample Preparation Procedure Prior to Multi-element Analysis of Slim Teas by ICP OES

The knowledge about mineral content of slim teas is of great importance since the consumption of these beverages has rapidly increased for the past several years. An increasing popularity of these tea products is mainly attributed to their nutritional properties, flavor, taste and health effects. Therefore, the main goal of the present work was to develop a precise and accurate method of the multi-element analysis of slim teas by inductively coupled plasma optical emission spectrometry (ICP OES) without the need for a laborious and tedious sample treatment preceding spectrometric measurements. Five sample preparation procedures, i.e., the total decomposition in a mixture of HNO3 and H2O2 solutions using closed vessel microwave-assisted or open vessel hot-plate systems, the solubilisation in aqua regia or a tetramethyl ammonium hydroxide solution and the extraction in a diluted HNO3 solution, were compared. The performance of the compared procedures was determined in terms of the precision and the accuracy of results achieved and limits of detection of elements. It was found that the solubilisation in aqua regia gave the best results, i.e., limits of detection between 0.15 and 98.4 ng l−1, the precision within 0.6−3.0 % and the accuracy better than 5 %. The developed method of the analysis, being a useful alternative to time-consuming wet digestion procedures, was successfully applied to the analysis of five slim tea products.

Two refractory Wild 2 terminal particles from a carrot‐shaped track characterized combining MIR/FIR/Raman microspectroscopy and FE‐SEM/EDS analyses

AbstractWe present the analyses results of two bulk Terminal Particles, C2112,7,171,0,0 and C2112,9,171,0,0, derived from the Jupiter‐family comet 81P/Wild 2 returned by the Stardust mission. Each particle embedded in a slab of silica aerogel was pressed in a diamond cell. This preparation, as expected, made it difficult to identify the minerals and organic materials present in these particles. This problem was overcome using a combination of three different analytical techniques, viz. FE‐SEM/EDS, IR, and Raman microspectroscopy that allowed identifying the minerals and small amounts of amorphous carbon present in both particles. TP2 and TP3 were dominated by Ca‐free and low‐Ca, Mg‐rich, Mg,Fe‐olivine. The presence of melilite in both particles is supported by IR microspectroscopy, but is not confirmed by Raman microspectroscopy, possibly because the amounts are too small to be detected. TP2 and TP3 show similar silicate mineral compositions, but Ni‐free and low‐Ni, subsulfur (Fe,Ni)S grains are present in TP2 only. TP2 contains indigenous amorphous carbon hot spots; no indigenous carbon was identified in TP3. These nonchondritic particles probably originated in a differentiated body. This work found an unanticipated carbon contamination following the FE‐SEM/EDS analyses. It is suggested that organic materials in the embedding silica aerogel are irradiated during FE‐SEM/EDS analyses creating a carbon gas that develops a strong fluorescence continuum. The combination of the selected analytical techniques can be used to characterize bulk Wild 2 particles without the need of extraction and removal of the encapsulating aerogel. This approach offers a relatively fast sample preparation procedure, but compressing the samples can cause spurious artifacts, viz. silica contamination. Because of the combination of techniques, we account for these artifacts.

Development and Validation of an In-House Database for Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry-Based Yeast Identification Using a Fast Protein Extraction Procedure

In recent studies evaluating the usefulness of the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)-based identification of yeasts for the routine diagnosis of fungal infections, preanalytical sample processing has emerged as a critical step for reliable MALDI-TOF MS outcomes, especially when the Bruker Daltonics Biotyper software was used. In addition, inadequate results often occurred due to discrepancies between the methods used for clinical testing and database construction. Therefore, we created an in-house MALDI-TOF MS library using the spectra from 156 reference and clinical yeast isolates (48 species in 11 genera), which were generated with a fast sample preparation procedure. After a retrospective validation study, our database was evaluated on 4,232 yeasts routinely isolated during a 6-month period and fast prepared for MALDI-TOF MS analysis. Thus, 4,209 (99.5%) of the isolates were successfully identified to the species level (with scores of ≥2.0), with 1,676 (39.6%) having scores of >2.3. For the remaining 23 (0.5%) isolates, no reliable identification (with scores of <1.7) was obtained. Interestingly, these isolates were almost always from species uniquely represented or not included in the database. As the MALDI-TOF MS results were, except for 23 isolates, validated without additional phenotypic or molecular tests, our proposed strategy can enhance the rapidity and accuracy of MALDI-TOF MS in identifying medically important yeast species. However, while continuous updating of our database will be necessary to enrich it with more strains/species of new and emerging yeasts, the present in-house MALDI-TOF MS library can be made publicly available for future multicenter studies.

A Rapid Quantification of β-Carotene in Fruits and Vegetables by Dispersive Liquid–Liquid Microextraction Coupled with UV–Vis Spectrophotometry: Optimized by Response Surface Methodology

A simple, fast, and efficient method consisted of optimized dispersive liquid–liquid microextraction (DLLME) followed by UV–vis spectrophotometry was developed for determination of β-carotene in fruits and vegetables. Chloroform and methanol were chosen as extraction and disperser solvents, respectively. The extraction process was optimized using a central composite design (CCD) with the optimum points of 115 μL for volume of extraction solvent and 6.5 % (w/v) for salt concentration. Under the optimal conditions, the relative standard deviation (RSD, C = 500 μg L−1, n = 5), limit of detection (LOD), linear dynamic range (LDR), and coefficient of determination (R2) were 1.08 %, 2 μg L−1, 50–1,500 μg L−1, and 0.991, respectively. The present method consisted of a simple and fast sample preparation procedure without any antioxidant addition, saponification, and purification was used.

A fast and simple procedure for determination of perfluoroalkyl substances in food and feed: a method verification by an interlaboratory study

In this study, a simple, fast, and cheap sample preparation procedure for the analysis of three well-known representatives of perfluoroalkyl substances (perfluorooctane sulfonate, perfluorooctanoic acid, and perfluorooctane sulfonamide) was validated in accordance with Commission Decision 2002/657/EC. The method was based on extraction with methanol followed by a dispersive solid phase extraction cleanup step by addition of activated charcoal for fish tissue, fish feed, and milk samples. The novel analytical approach combined with liquid chromatography-tandem mass spectrometry makes it possible to achieve limits of quantification below 1μg/kg (defined by Commission Recommendation 2010/161/EU). This method provides a high laboratory sample throughput: ten samples in 60min. The validated procedure was successfully verified in an interlaboratory study.