Solid-phase Extraction Clean-up Research Articles

Polycyclic aromatic hydrocarbons in harvested rainwater in Warri and Agbarho, Nigeria

ABSTRACT. The aim of this research was to provide an overview of current knowledge, by assessing the possible contamination sources of harvested rainwater by polycyclic aromatic hydrocarbons (PAHs), its effects and possible human health risk assessment. Random sampling technique was used to collect eight rainwater samples from different roofing materials made from (asbestos, zinc, aluminium and thatch) in Warri and Agbarho (AGB). The samples were extracted using a liquid-liquid extraction (LLE) system according to the established procedures of United States Environmental Public Agency (USEPA). Under the optimized conditions, the ranges of extraction recoveries and solid-phase extraction (SPE) clean-up of the PAHs in the harvested rainwater were in the range of 71-90%. Gas chromatography-mass spectrometry (GC-MS) was used for the determination of the sixteen priority PAHs in the samples. The total concentration of PAHs for each of the roof types in Warri Refinery Petrochemical Company (WRPC) are: 0.036±0.012, 0.047±0.020, 0.045±0.018 and 0.0023±0.008 ppm for aluminium, zinc, asbestos and thatch roof, respectively. In addition, total concentration of PAHs for each of the roof types in AGB are: 0.046±0.020, 0.024±0.009, 0.023±0.008 and 0.021±0.007 ppm for aluminium, zinc, asbestos and thatch roof. The PAHs analysed exceeded the United States environmental protection agency (USEPA) standards of contamination.
 
 KEY WORDS: AGB, GC-MS, Harvested Rainwater, LLE, PAHs, WRPC
 Bull. Chem. Soc. Ethiop. 2022, 36(4), 779-789. 
 DOI: https://dx.doi.org/10.4314/bcse.v36i4.5

Determination of pharmaceuticals and metabolites in sludge and hydrochar after hydrothermal carbonization using sonication-QuEChERS extraction method and UHPLC LTQ/Orbitrap MS.

Pharmaceuticals (PhACs) are an important group of emerging contaminants that are released continuously in the environment from wastewater treatments plants (WWTPs). They can produce biological effects even though at very low concentrations. Conventional WWTPs are not able to remove or degrade completely emerging pollutants resulting in the presence of PhACs in sewage sludge after wastewater treatment. PhACs are found in sludge at low ppb-ppt levels, and their analysis and detection is a difficult task due to the complexity of sewage sludge matrices. Hydrothermal carbonization is currently being proposed as a suitable conversion technology for sewage sludge management to recover valuable products and to be used for soil amendment. In this work, a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based methodology with a dispersive solid-phase extraction (d-SPE) clean-up followed by ultra-high-performance liquid chromatography coupled with high-resolution linear ion trap-Orbitrap mass spectrometry (UHPLC-LTQ/Orbitrap MS), operated in positive ionization mode, was adopted to investigate 33 multiclass pharmaceuticals in sewage sludge and in hydrochar produced after hydrothermal carbonization. The analytical method was first optimized studying various extraction parameters and finally validated in terms of linearity, recovery, intra and inter-day precisions, expanded uncertainty (%U)/Horrat ratio at three spiking levels, matrix-effects (ME), process efficiency (PE), and limits of detection and quantification. The developed methodology fulfilled all analytical requirements and was finally applied to sludge samples from the WWTP of Ioannina city where a group of antibiotics was detected at concentrations up to 15ngg-1 and psychiatric drugs such as amisulpride, clozapine, and citalopram were detected at higher concentration levels up to 205, 87.4 and 63.2ngg-1, respectively. The method was also applied to hydrothermally treated sludge sample under different reaction conditions. Most of the antibiotic compounds were not detected, and several psychiatric drugs such as mirtazapine, bupropion, valsartan, diazepam, and caffeine were found at concentrations below the LOQ.

Improved Method for Accurate and Efficient Analysis of Chlorophenols in Leather Compared with Conventional Steam Distillation Operation Specified by ISO 1707:2015

An improved analytical method was built based on the conventional standard method ISO 17070-2015 for the determination of 19 chlorophenols in leather. This developed method involved ultrasonic assisted extraction using methanol containing formic acid, derivatization using acetic anhydride, solid-phase extraction (SPE) cleanup with silica-gel cartridge. Final analysis of the chlorophenols compounds was performed by Gas Chromatography - Mass Spectrometry (GC-MS). Optimum conditions for sample extraction, such as time, temperature and formic acid content in methanol were studied. Satisfactory recoveries in the range of 92-105% (RSD, 2.1-7.3%) for the targets were obtained, and detection limits were in the range of 0.09-0.15 mg/kg. The developed procedure was evaluated and compared with ISO 17070-2015 which uses steam distillation for sample extraction. The method was successfully applied to determine 19 chlorophenols in series of leather samples from different origin. This study demonstrated that the ultrasonic assisted extraction, followed by acetyl derivatization and silica-gel cleanup coupled with GC-MS, can be used as an alternative to ISO 17070-2015, for detecting chlorophenols in leather.

Determination of pesticides and their degradation products in sediment samples by accelerated solvent extraction and solid-phase extraction with high-performance liquid chromatography-high-resolution mass spectrometry.

A new sensitive and selective methods was developed to quantify different types of pesticides and their degradation products in sediment. The method developed was optimized and modified based on the accelerated solvent extraction, followed by the solid-phase extraction clean-up technique. High-performance liquid chromatography coupled with mass spectrometry was used for analysis. The influence of various parameters on the extraction process was investigated, including the extraction temperature, extraction solvent, purification column and purification solvent, etc. Under the optimal conditions, the relative recoveries of the pesticides and their degradation products ranged from 80 to 106% for spiked blank sediment and environmental sediment samples with relative standard deviations of 1-9%. The method displayed low method detection limits for both sediment matrices and achieved good linearity over the tested range of concentrations. The physical and chemical properties of sediment showed that high content of sediment water content and humic acid would affect the extraction efficiency of sample pretreatment. The method was applied to environmental sediment to quantify pesticide residues in the samples. Based on the instrument and method performance validation results, the developed methods can be applied in environmental pesticide residue analysis, thus providing a scientific method for the detection of sediment samples.

An antibody-free platform for multiplexed, sensitive quantification of protein biomarkers in complex biomatrices

Sensitive, multiplexed protein quantification remains challenging despite recent advancements in LC-MS assays for targeted protein biomarker quantification. High-sensitivity protein biomarker measurements usually require immuno-affinity enrichment of target protein; a process which is highly dependent on capture reagent and limited in capability to measure multiple analytes. Herein, we report a novel antibody-free platform, which measures multiple biomarkers from complex matrices employing a strategically optimized solid-phase extraction cleanup and orthogonal multidimensional LC-MS. Eight human protein biomarkers with different specifications were spiked into canine plasma as a model investigation system. The developed strategy achieved the desired sensitivity, robustness, and throughput via the following steps: (1) post digestion mixed-mode cation exchange-reverse phase SPE enrichment cleaned up the sample initially; (2) rapid, high-pH peptide fractionation further eliminated background components efficiently while selectively enriched signature peptides (SP) to provide sufficient sensitivity for multiple targets; and (3) trapping-micro-LC-MS analysis delivered high sensitivity comparable to a nano-LC-MS method but with much better robustness and throughput for the final analysis. Compared with a conventional LC-MS assay with direct protein digestion and limited clean-up, analysis with this antibody-free platform improved the LLOQ by 1–2 orders of magnitude for the eight protein biomarkers, reaching as low as 5 ng/mL in plasma, with feasible robustness and throughput. This platform was applied for the quantification of biomarkers of respiratory conditions in patients with various lung diseases, demonstrating real-world applicability.

Widespread occurrence of emerging E-waste contaminants – Liquid crystal monomers in sediments of the Pearl River Estuary, China

Liquid crystal monomers (LCMs), commonly used in screens of electronic devices, have recently been identified as a group of emerging chemicals of concern associated with e-waste. They are potentially persistent, bioaccumulative, and toxic substances, and may pose a threat to the marine ecosystem. The Pearl River Estuary (PRE) receives organic contaminants discharged from the Pearl River Delta region, where primitive handling of e-waste is widespread. However, information on the pollution status of LCMs in the PRE is absent. Herein, a rapid and robust analytical method was established using ultrasonic extraction, solid phase extraction cleanup, and GC-Orbitrap-MS analysis. The spatial distribution of 39 target LCMs was investigated in 45 surface sediment samples from the PRE. Ten LCMs were detected, with ΣLCMs ranged from 0.9 to 31.1 ng/g dry weight. Our results demonstrated a widespread occurrence of LCMs in the sediments of the PRE, and a gradient of their contamination from inshore to offshore regions, indicating land-based origins. Our reported ΣLCMs concentrations were relatively higher compared to many other legacy and emerging pollutants found in the same investigated area. Preliminary risk assessment showed 3VbcH, Pe3bcH and tFMeO-3bcHP might be the top 3 risk contributors in the PRE. Further investigation on the ecological impact of LCMs on marine benthic ecosystems, as well as identification of their sources and control measures are warranted.

Bisphenol A in edible tissues of rams exposed to repeated low-level dietary dose by high-performance liquid chromatography with fluorescence detection

The presented work deals with levels and distribution of bisphenol A (BPA) in the edible tissues of a large food-producing animal species. An experimental animal study included 14 young Istrian pramenka rams (Ovis aries), of which seven were exposed for 64 days to a low dietary dose of BPA at 25 µg/kg b.w./day, and seven served as a control group. Residue analysis of both aglycone and total BPA was performed in the muscle tissue, liver, kidney and fat tissue of the individual animals by means of enzymatic deconjugation (for total BPA), organic solvent extraction, molecularly imprinted polymer solid-phase extraction (MISPE) clean-up and high-performance liquid chromatography with fluorescence detection (HPLC-FLU). The analysis was optimized and validated for aglycone BPA in the fat tissue and for the total BPA in all tissues investigated. Edible tissues of the control group of rams generally remained BPA-free, while there were concentration differences between the control and treated groups for liver and kidney post last administration. The human health risk resulting from this study was assessed by the estimated dietary exposure in adults, which was < 0.1% related to the valid European Union Tolerable Daily Intake (TDI) value of 4 µg/kg b.w./day. However, it would be 58-fold higher than the newly proposed TDI value of 0.04 ng/kg b.w./day.

Method development and optimisation for analysis of pesticide residues in biological matrices by modified QuEChERS and gas chromatography–triple quadrupole mass spectrometry

ABSTRACT A rapid and precise modified QuEChERS method for extraction was developed for simultaneous quantitation of multi-class pesticide residues in human biological matrices, viz. blood, serum and urine. In the modified QuEChERS method, targeted analytes in biological sample were extracted using acidified solution of acetonitrile and ethyl acetate along with anhydrous MgSO4. The collected aqueous layer was evaporated and dispersive solid-phase extraction clean-up was performed. The pesticide residues were assessed using gas chromatography–tandem mass spectrometry with multiple reaction monitoring mode. The developed method was validated as per European Union SANTE/12682/2019 guidelines and the evaluated method validation parameters, viz. linearity, limit of detection, limit of quantitation, accuracy, %relative standard deviation and matrix effect were found to be satisfactory. The proposed method is easy, comprehensible and efficient for simultaneous analysis of diverse range of pesticide residues within similar class. Hence, the present solitary method can be used for systematic analysis of biological samples.

Precolumn Derivatization High-Performance Liquid Chromatography for Determination of Perfluorocarboxylic Acids in Catalytic Degradation Solutions.

Perfluoroalkyl carboxylic acids (PFCAs), a series of ubiquitous contaminants in the global environment, attracted much attention due to their potential for high bioaccumulation and toxicity to various organisms. There are a lot of measurement requests in currently increasing degradation studies of PFCAs, which usually rely on expensive liquid chromatography-mass spectrometry (LC-MS). The degradation solutions containing high-concentration PFCAs can easily cause the pipeline pollution of the LC/MS instrument, which is usually used for trace analysis of environmental samples. In this study, a simple and reliable precolumn derivatization LC method coupled with an ultraviolet detector (UV) was developed for the determination of the main PFCAs (C4-9) of environmental concern. These PFCAs in degradation solutions were crosslinked to UV-responsive 3, 4-diphenylamine (DCA) by a carbodiimidization method, followed by a simple solid-phase extraction (SPE) cleanup, and quantitatively measured using a conventional LC-UV instrument. Compared to previously reported precolumn derivatization methods, this new derivatization approach has the advantages such as mild reaction conditions, easy operation, enhanced stability of derivatives, and low cost. The instrumental limits of detection (ILDs) for the targeted PFCAs in organic and aqueous mediums were 0.2–0.5 and 0.6–1.5 mg/L, respectively. The method has been successfully applied to the determination of PFCAs in catalytic degradation solutions and recommended for use in other assays involving relatively high-concentration PFCAs.

Targeted and non-targeted analysis of pesticides and aflatoxins in baby foods by liquid chromatography coupled to quadrupole Orbitrap mass spectrometry

In this study, 21 pesticides and 4 aflatoxins were monitored in baby food marketed in Brazil, applying ultra-high-performance liquid chromatography coupled to quadrupole-Orbitrap mass spectrometry (UHPLC-Q-Orbitrap-MS). The quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction method combined with dispersive solid-phase extraction (d-SPE) clean-up was applied and primary secondary amine (PSA), octadecylsilane (C18) and C18 with silica coated with zirconium dioxide (Z-Sep+) were used during the clean-up stage. Suitable performance criteria, set by the SANTE/2020/12830 guidelines, were achieved, and therefore, all targeted analytes were successfully validated. The method was applied to the analysis of 50 baby food samples. Cypermethrin was detected at 10.3 μg kg−1 (above maximum residue level (MRL) established by the European Union (EU)). Furthermore, suspect screening analysis was performed for reliable identification of contaminants not included in this study such as other pesticides, mycotoxins, hormones, veterinary drugs and their metabolites. Finally 10 pesticides and one metabolite were detected, demonstrating the suitability of the proposed approach.

Simultaneous focused ultrasound solid–liquid extraction and dispersive solid-phase extraction clean-up for gas chromatography–tandem mass spectrometry determination of polycyclic aromatic hydrocarbons in crustacean gammarids meeting the requirements of the European Union Water Framework Directive

The study presents the development and validation of a method for the determination of seven priority polycyclic aromatic hydrocarbons (PAHs, including fluoranthene and benzo[a]pyrene, for which the EU has set environmental quality standards, EQS, for biota) in gammarid samples combining focused ultrasound solid–liquid extraction and dispersive solid-phase extraction clean-up in one step followed by gas chromatography–triple quadrupole tandem mass spectrometry (GC–QqQ-MS/MS). The method is designed to analyse small about 100 mg dry weight (dw) samples obtained after lyophilisation of 500 mg wet weight (ww) samples. The sample preparation procedure is simple, environment friendly (method was classified as “an excellent green analysis” according to the analytical Eco-Scale assessment), non-laborious and low-cost and, apart from the sample extract concentration step, is quick. Thorough disintegration of the gammarids is achieved by a combination of sonication and the addition of granular anhydrous Na2SO4 to the gammarid suspension, thus avoiding the need to grind the sample prior to analysis. The QqQ-MS/MS detector, thanks to its excellent selectivity and sensitivity, allows to meet the EQS requirements for PAHs in biota with a good margin (limits of quantification in the range of 0.12 and 0.56 ng g‒1 ww). The method has been successfully validated (in terms of linearity, method limits, precision, trueness, robustness, measurement uncertainty and comparative analysis of real samples), and has been shown to be suitable for monitoring and evaluating the PAHs contamination in surface water biota.

Residue Behavior of Clopyralid Herbicide in Soil and Sugar Beet Crop under Subtropical Field Conditions

Sugar beet is a major crop for the sugar industry. With growing awareness of unsystematic use of pesticides, health problem, and environmental issues, assessment of pesticide residues in soil and crops has become necessary. Studies of subtropical conditions on dissipation and residue analysis of clopyralid have not yet been reported. Therefore, dissipation kinetics and terminal residues of clopyralid for two cropping seasons in the soil and the sugar beet crop were studied under field conditions. An experiment was laid out in a randomized block design, and a herbicide was applied as a postemergent. Clopyralid was extracted from the matrix by basic water, subjected to solid phase extraction cleanup, and quantified by high-pressure liquid chromatography-UV. The method was validated, and recovery percentage of pesticide ranged from 81 to 88, 77 to 85, 78 to 86, and 89 to 94% in the soil, sugar beet roots, sugar beet leaves, and water, respectively. After application in the soil, clopyralid dissipated rapidly following monophasic first-order kinetics, with a half-life of 13.39 days. Limits of detection and quantitation were 0.007 and 0.02 μg g-1, respectively. Clopyralid does not persist long in soil, and residues were below the European Union's maximum residue levels (0.5 mg kg-1) in the roots and leaves of sugar beet. Residues were also not detected in the groundwater. It can be concluded that clopyralid could be considered a safe herbicide from the environmental aspect due to its nonpersistence and that it would not have an adverse effect on human or animal health.

Occurrence of polycyclic aromatic compounds in guarana (Paullinia cupana) seeds subjected to different drying processes

In this study, the levels of polycyclic aromatic compounds (PACs), such as polycyclic aromatic hydrocarbons (PAHs) and their oxygenated derivatives (oxy-PAHs) were investigated in guarana seeds (Paullinia cupana) subjected to different drying methodologies. An innovative extraction method combined with a miniaturized dispersive solid-phase extraction cleanup procedure was developed for the determination of PACs concentration. Thirteen-eight guarana seed samples subjected to three different drying methodologies (sun drying, greenhouse drying, and alguidar furnace drying) were collected from different rural producers in the South Region of the State of Bahia, Brazil. Principal component analysis and diagnostic ratios were used to evaluate the correlation between samples and the PACs and the main sources of contamination. According to the results, the average concentration of PACs found in sun-dried, greenhouse-dried, and alguidar-dried ranged from 1.30 µg kg−1 (coronene) to 114 µg kg−1 (fluorene), from 0.48 µg kg−1 (dibenzo[a,h]anthracene) to 128 µg kg−1 (fluorene), and from 6.0 µg kg−1 (anthracene) to 422 µg kg−1 (phenanthrene). Oxy-PAHs, such as 1,4-NQ was detected predominantly in sun-dried and greenhouse-dried samples at concentrations ranging from 30.7 µg kg−1 to 83.9 µg kg−1. Low molecular weight PAHs, such as naphthalene, acenaphthylene, and fluorene were found in most of the samples independently of drying methodology. However, high molecular weight PAHs, including the carcinogenic benzo[a]pyrene was found predominately in alguidar-dried samples in concentrations higher than 20 µg kg−1.

A novel single step solid-phase extraction combined with bromine derivatization method for rapid determination of acrylamide in coffee and its products by stable isotope dilution ultra-performance liquid chromatography tandem triple quadrupole electrospray ionization mass spectrometry

This work aimed to establish a novel determination method for acrylamide in coffee and its products by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Acrylamide in samples were prepared by a single-step solid-phase extraction clean-up using mixed mode sorbents. The bromine derivatization efficiency of acrylamide and its internal standard were improved at an acidic condition. After derivation, the retention capability of acrylamide and its resistance to interference were significantly improved. The limit of detection (LOD) and the limit of quantification (LOQ) were 1.2 and 4 μg/kg for roasted and instant coffees, while they were 0.24 and 0.8 μg/kg for ready-to-drink coffees. The average recoveries for acrylamide ranged from 99.3 to 102.2% in coffee and its products. All the results showed that the developed method was simple, quick, specific and suitable for screening and determination of acrylamide in batch samples of coffee and its products.

Unexpected sensitivity enhancement in analysing alfatoxin M1 using LC-IDMS

Aflatoxin M1 (AFM1) and patulin (PAT) are regulated mycotoxins, which are generally analyzed in food samples alone (“one analyte at a time”). This paper presents the development of a liquid chromatography isotope dilution tandem mass spectrometric (LC-IDMS) method for the determination of AFM1 in milk-based products, which method was then successfully applied to PAT in apple-based food samples. The method involved a selective solid-phase extraction clean-up at acidic pH employing mixed-mode cation exchange cartridges. The purification allowed the adequate adsorption of neutral target compounds and basic matrix constituents of the sample to the reversed-phase (RP) and to the cation exchange phase of the cartridge, respectively. The sample elution with pure methanol yielded an extract free from basic matrices. The remaining acidic and neutral matrix constituents of the samples were separated from the analytes using mixed-mode anion exchange HPLC column. Mobile phases without any modifiers were used for the highest sensitivity and better selectivity. The intensity enhancement obtained by neutral eluent composition was inter-laboratory tested and confirmed on same type of instruments. The sample preparation requires low amount of organic solvent, thus adhered to green analytical chemistry. The developed method for analyzing AFM1 resulted in low matrix effect of LC-IDMS separation −4.9-(−1.5%) and high precision (2.7–5.9%), calculated under method validations at spiking levels between 0.005 and 0.050 µg/kg. Method performance characteristics for analyzing PAT were also evaluated at 10 and 25 µg/kg levels. Finally, the advantageous features of the newly developed method were briefly compared and discussed with the existing approaches.

Development and validation of a highly effective analytical method for the evaluation of the exposure of migratory birds to antibiotics and their metabolites by faeces analysis

The widespread occurrence of antibiotics in the environment may exert a negative impact on wild organisms. In addition, they can become environmental reservoirs, through the ingestion of food or contaminated water, and vectors for antibiotic-resistant bacteria. This fact is even more important in migratory birds that can promote their dissemination across continents. In this work, a multiresidue analytical method suitable for the determination of five families of antibiotics and their main metabolites in waterbird faeces has been developed and validated. The target compounds include environmentally significant sulfonamides, macrolides, fluoroquinolones, tetracyclines and antifolates. Sample treatment involves ultrasound-assisted extraction with methanol and dispersive solid-phase extraction clean-up with C18. Analytical determination was carried out by liquid chromatography–tandem mass spectrometry. The most significant parameters affecting sample extraction and extract clean-up were optimised by means of experimental designs. Good linearity (R2 > 0.994), accuracy (from 41 to 127%), precision (relative standard deviation lower than 24%) and limits of quantification (lower than 2 ng g−1 (dry weight, dw)) were obtained for most of the compounds. The method was applied to the determination of the selected compounds in 27 faeces samples from three common migratory waterbird species. Nine antibiotics and three of their metabolites were detected in the analysed samples. Fluoroquinolones and macrolides were the antibiotics most frequently detected. The highest concentrations corresponded to norfloxacin (up to 199 ng g−1 dw).Graphical abstract

A fast and simple PFAS extraction method utilizing HR–CS–GFMAS for soil samples

Here, we describe an optimized fast and simple extraction method for the determination of per- and polyfluorinated alkyl substances (PFASs) in soils utilizing high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR–CS–GFMAS). To omit the bias of the solid phase extraction (SPE) step commonly used during the analysis of extractable organically bound fluorine (EOF) we optimized a fast and simple SPE-free extraction method. The developed extraction method consists of a liquid-solid extraction using acidified methanol without any additional SPE. Four extraction steps were representative to determine a high proportion of the EOF (>80% of eight extractions). Comparison of the optimized method with and without an additional SPE clean-up step revealed a drastic underestimation of EOF concentrations using SPE. Differences of up to 94% were observed which were not explainable by coextracted inorganic fluoride. Therefore, not only a more accurate but also a more economic as well as ecologic method (bypassing of unnecessary SPE) was developed. The procedural limit of quantification (LOQ) of the developed method was 10.30 μg/kg which was sufficient for quantifying EOF concentrations in all tested samples. For future PFAS monitoring and potential regulative decisions the herein presented optimized extraction method can offer a valuable contribution.

Suspected-screening assessment of the occurrence of organic compounds in sewage sludge

The profiling of emerging organic pollutants present in sludge and generated during wastewater treatment is much more limited than in water. This is mainly due to the difficulty of sludge analysis because of its high content of organic matter and interfering compounds. In this study, a generic extraction method using a mixture of buffered water (pH 4.1) and solid phase extraction (SPE) clean-up was applied to samples of sludge obtained in different treatment plants. This extraction was followed by determination of the contaminants by ultra-high performance liquid chromatography coupled to high resolution mass spectrometry (UHPLC-HRMS), using suspected screening to detect the most relevant organic compounds that access the environment through sludge application. This screening (including >3000 substances, such as, pharmaceuticals, pesticides, metabolites and industrial chemicals) tentatively identified 122 compound and assigned most probable structure to 39. The set of compounds assigned to a probable structure was increased in 14 compounds by searching in a free database of metabolites. Fifteen compounds were unequivocally confirmed against the analytical standard. Pharmaceuticals and personal care products (PPCPs), with 31 substances identified and 8 confirmed were the main group of compounds. Compounds frequently detected in all sludge samples include nucleotides such as adenosine triphosphate, amino acids such as phenylalanine, or peptides such as leu-phe. Altogether, the results of this work highlight the interest of HRMS to draw the profile of organic compounds in complex matrices.

Ultrasonic Solvent Extraction Followed by Dispersive Solid Phase Extraction (d-SPE) Cleanup for the Simultaneous Determination of Five Anthraquinones in Polygonum multiflorum by UHPLC-PDA.

A rapid and effective ultra-high performance liquid chromatography (UHPLC) method was developed for the determination of five anthraquinones (emodin, physcion, aloe-emodin, rhein, and chrysophanol) in Polygonum multiflorum. The target compounds were ultrasonically extracted with 70% methanol, followed by dispersive solid-phase extraction (d-SPE) with HC-C18 and desorption with acetonitrile. The five anthraquinones were separated on an ACQUITY UPLC® HSS T3 column (2.1 × 100 mm, 1.8 μm) and detected by a photodiode array detector (PDA) at 254 nm. Under the optimized conditions, linear relationships were achieved in the range of 0.3~100 mg/L for emodin, 0.3~40 mg/L for physcion, 0.1~20 mg/L for aloe-emodin, and 0.05~20 mg/L for rhein and chrysophanol. The limits of detection of the five analytes ranged from 0.01 to 0.08 mg/L, and the recoveries were within the range of 82.8~118.4% with an RSD (n = 6) of 1.0~10.3%. The intra-day and inter-day precision (n = 5) of the five targets were in the range of 1.0~1.8% and 3.0~3.1%, respectively. Furthermore, this method was applied to analyses of Polygonum multiflorum samples collected from different regions in China with satisfactory results. All the results indicated that this method is suitable for the detection of five anthraquinones in Polygonum multiflorum.

Analysis of acrylamide in vegetable chips after derivatization with 2-mercaptobenzoic acid by liquid chromatography\u2013mass spectrometry

Since many years, acrylamide (AA) is a well-known toxicologically relevant processing contaminant (“food-borne toxicant”). However, only during the recent years, high levels of acrylamide have been reported in vegetable chips. In the present study, AA was quantitated via a modified derivatization procedure with 2-mercaptobenzoic acid based on stable isotope dilution analysis and liquid chromatography–mass spectrometry. Extraction with a modified QuEChERS (quick, easy, cheap, efficient, rugged, safe) method, defatting with n-hexane, and a solid phase extraction clean-up with strong cation-exchange material were performed prior to the derivatization step. Limits of detection and quantitation (LoD and LoQ) were 12 and 41 µg of AA/kg of vegetable chips (estimated via signal-to-noise ratios of 3:1 and 10:1, respectively), and thus below the LoQ of 50 µg/kg requested by the European Food Safety Authority. Recovery rates between 92 and 101% at four spiking levels with a good precision expressed as a relative standard deviation < 7% were determined. With this method at hand, a survey of the current AA amounts in 38 vegetable chips from the worldwide market was performed, showing a remarkable variability between the different vegetables, but also between different products of the same vegetable. Thereby, the AA amounts ranged between 77.3 and 3090 µg/kg, with an average of 954 µg/kg which was distinctly higher in comparison to commercially available potato chips also analyzed in the present study (12 samples, range: 117–832 µg/kg, average: 449 µg/kg). While for sweet potato and parsnip relatively low AA amounts were found, beetroot and carrot showed rather high contents.