Evaluation of a new column backflushing set-up in the gas chromatographic–tandem mass spectrometric analysis of pesticide residues in dietary supplements

Stability Study and Handling Recommendations for Multiresidue Pesticide Mixes under Diverse Storage Conditions for LC-MS/MS and GC-MS/MS

BACKGROUND

In response to the growing global need for pesticide residue testing, laboratories must develop versatile analytical methods and workflows to produce scientifically sound results. One of the many challenges faced by food chemists is acquiring suitable pesticide certified reference materials (CRMs) to calibrate analytical equipment, monitor method performance, and confirm the identity and concentration of hundreds of pesticide residues in food samples. CRM producers invest considerable resources to ensure the stability of their products.

OBJECTIVE

To present proper CRM handling and storage practices as guidance to ensure stability based on the results of several multiresidue pesticide stability studies.

METHODS

The open ampoule and combined multiresidue mix studies were conducted under controlled conditions. New ampoules containing multiresidue pesticide CRM mixtures were opened and compared to previously opened ampoules at multiple intervals while stored under freezing and refrigerated temperatures. Both LC- and GC-amenable pesticides (>200 residues) were combined and stored under typical laboratory conditions. Studies were performed with and without celery matrix.

RESULTS

The open ampoule study showed high levels of stability for all mixtures. All GC residues remained stable over the duration of the experiment. A week after opening LC multiresidue pesticide mixtures showed minor degradation. After combination of the multiresidue pesticide mixtures, degradation occurred rapidly for both the GC and LC mixtures.

CONCLUSION

Multiresidue pesticide mixtures are stable as ampullated until they are opened. Once the contents of a kit were opened and combined, decreasing stability was observed over time. This was true for both the LC and GC kits. Working mixtures of CRMs for instrument calibration should be made daily.

HIGHLIGHTS

This article shows a novel approach for measuring stability of CRM mixes. In-depth analysis of multiresidue pesticide mixtures and the stability that can be expected before and after mixing under typical storage conditions is described.

Cyanobacteria as a Valuable Natural Resource for Improved Agriculture, Environment, and Plant Protection

Taking into consideration, the challenges faced by the environment and agro-ecosystem make increased for suggestions more reliable methods to help increase food security and deal with difficult environmental problems. Environmental factors play a critical role in the growth, development, and productivity of crop plants. Unfavorable changes in these factors, such as abiotic stresses, can result in plant growth deficiencies, yield reductions, long-lasting damage, and even death of the plants. In reflection of this, cyanobacteria are now considered important microorganisms that can improve the fertility of soils and the productivity of crop plants due to their different features like photosynthesis, great biomass yield, ability to fix the atmospheric N2, capability to grow on non-arable lands, and varied water sources. Furthermore, numerous cyanobacteria consist of biologically active substances like pigments, amino acids, polysaccharides, phytohormones, and vitamins that support plant growth enhancement. Many studies have exposed the probable role of these compounds in the alleviation of abiotic stress in crop plants and have concluded with evidence of physiological, biochemical, and molecular mechanisms that confirm that cyanobacteria can decrease the stress and induce plant growth. This review discussed the promising effects of cyanobacteria and their possible mode of action to control the growth and development of crop plants as an effective method to overcome different stresses.

Graphical Abstract

Microalgal-induced remediation of wastewaters loaded with organic and inorganic pollutants: An overview

The recent surge in industrialization has intensified the accumulation of various types of organic and inorganic pollutants due to the illegal dumping of partially and/or untreated wastewater effluents in the environment. The pollutants emitted by several industries pose serious risk to the environment, animals and human beings. Management and diminution of these hazardous organic pollutants have become an incipient research interest. Traditional physiochemical methods are energy intensive and produce secondary pollutants. So, bioremediation via microalgae has appeared to be an eco-friendly and sustainable technique to curb the adverse effects of organic and inorganic contaminants because microalgae can degrade complex organic compounds and convert them into simpler and non-toxic substances without the release of secondary pollutants. Even some of the organic pollutants can be exploited by microalgae as a source of carbon in mixotrophic cultivation. Literature survey has revealed that use of the latest modification techniques for microalgae such as immobilization (on alginate, carrageena and agar), pigment-extraction, and pretreatment (with acids) have enhaced their bioremedial potential. Moreover, microalgal components i.e., biopolymers and extracellular polymeric substances (EPS) can potentially be exploited in the biosorption of pollutants. Though bioremediation of wastewaters by microalgae is quite well-studied realm but some aspects like structural and functional responses of microalgae toward pollutant derivatives/by-products (formed during biodegradation), use of genetic engineering to improve the tolerance of microalgae against higher concentrations of polluatans, and harvesting cost reduction, and monitoring of parameters at large-scale still need more focus. This review discusses the accumulation of different types of pollutants into the environment through various sources and the mechanisms used by microalgae to degrade commonly occurring organic and inorganic pollutants.

Development and Validation of a Modified QuEChERS Method for Simultaneous Analysis of 250 Flavor Constituents in Tobacco by Gas Chromatography Tandem Mass Spectrometry

BACKGROUND

Flavor constituents play an important role in the flavor characteristics of tobacco leaves and cigarettes. Sensitive, selective, and high-throughput multi-analyte analytical methods are needed to satisfy the demand for analyzing trace-level flavor constituents in tobacco. However, trace analysis of multi-targets in a complex tobacco matrix is significantly challenging.

OBJECTIVE

This study was undertaken to develop and validate a fast, selective, sensitive, and accurate GC-tandem mass spectrometry (GC-MS/MS) method for the simultaneous analysis of 250 flavor constituents in tobacco using a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) extraction procedure and backflushing technique.

METHODS

The samples were extracted with a mixture of acetonitrile and phosphate buffer. GC-MS/MS served as a reliable tool to quantify the flavor constituents due to its high sensitivity, selectivity, and good repeatability.

RESULTS

Our evaluation showed that 243 flavor constituents presented good linearity. Average recoveries of 216 target compounds in tobacco ranged from 70 to 120% with RSDs less than 20% at three fortification levels. The limits of quantitation of 225 and 25 compounds were in the range of 2-50 and 51-112 μg/kg, respectively. This method was then successfully applied to the analysis of 15 commercial cigarette samples with different style characteristics.

CONCLUSION

The modified QuEChERS method worked very well for a wide range of flavor constituents that have not been reported by QuEChERS pretreatment previously, and the use of concurrent backflushing offered significant increase in system robustness and sample throughput. The method greatly improved the detection performance and the range of the flavor constituents, and proved to be more accurate, sensitive, selective, convenient, and practical than the reported method, and thus, can be applied in routine analysis.

HIGHLIGHTS

A validated QuEChERS-based GC-MS/MS method for multiple flavor constituents analysis in tobacco was reported for the first time. The use of concurrent backflushing markedly improved the instrument robustness and sample throughput.

Robust, comprehensive, sensitive analysis of flavour additives with carboxyl and hydroxyl groups in cigarette smoke combining silylation and gas chromatography-tandem mass spectrometry with an improved backflushing system

Flavour additives with carboxyl and hydroxyl groups (FACHs), the key ingredients in characteristic flavours, are frequently detected in cigarette smoke. They are attracting increasing attention in regulating the flavour additives used in tobacco to curb youth tobacco use and prevent the use of additives that are harmful. In this study, a highly robust, sensitive, and precise method based on silylation and GC-MS/MS with an improved backflushing system was developed for the simultaneous analysis of 171 FACHs in cigarette smoke. Silylation has been shown to have advantages in terms of high selectivity and sensitivity to chemicals with carboxyl and hydroxyl groups, especially when combined with GC-MS/MS. The extraction and silylation conditions were optimised. Dichloromethane was used as the extraction agent. BSTFA in combination with 1% TMCS and 0.2% TMSI was selected as silylating agent for high silylation efficiency, particularly for hindered analytes. The method has been validated. The limit of detection (LOD) ranged from 0.6 to 332.3 ng/mL. 91.1% out of the analytes in QC samples had precisions lower than 10% during one month run. The improved backflushing system with a fused silica splitter was shown to be crucial in the excellent long-term robustness of the method. The developed method was used to determine flavour additives in 270 practical cigarette smoke samples with reliable results. A total of 154 FACHs were identified with wide-range levels among different cigarette brands.

Mycotoxins along the tea supply chain: A dark side of an ancient and high valued aromatic beverage

ABSTRACTSTea (Camellia sinensis L.) is a high valued beverage worldwide since ancient times; more than three billion cups of tea are consumed each day. Leaf extracts of the plant are used for food preservation, cosmetics, and medicinal purposes. Nevertheless, tea contaminated with mycotoxins poses a serious health threat to humans. Mycotoxin production by tea fungi is induced by a variety of factors, including poor processing methods and environmental factors such as high temperature and humidity. This review summarizes the studies published to date on mycotoxin prevalence, toxicity, the effects of climate change on mycotoxin production, and the methods used to detect and decontaminate tea mycotoxins. While many investigations in this domain have been carried out on the prevalence of aflatoxins and ochratoxins in black, green, pu-erh, and herbal teas, much less information is available on zearalenone, fumonisins, and Alternaria toxins. Mycotoxins in teas were detected using several methods; the most commonly used being the High-Performance Liquid Chromatography (HPLC) with fluorescence detection, followed by HPLC with tandem mass spectrometry, gas chromatography and enzyme-linked immunosorbent assay. Further, mycotoxins decontamination methods for teas included physical, chemical, and biological methods, with physical methods being most prevalent. Finally, research gaps and future directions have also been discussed.

A Review of Microalgae- and Cyanobacteria-Based Biodegradation of Organic Pollutants

This review proposes a new bioremediation method based on the diverse functionalities of algae. A greenway for cleansing wastewater is more ecologically friendly and environmentally sustainable than prior methods with other bacteria. New bioremediation technology employing algae and cyanobacteria for the removal of a wide range of organic contaminants is reasonable and has great potential. The prevalence of organic contaminants in aquatic habitats may endanger the health and well-being of several marine creatures. Agriculture, industry, and household trash are just a few of the human-caused sources of organic pollutants that contaminate waterways around the world. Before wastewater can be released into waterways, it must be cleaned. Algae-based wastewater treatment systems are becoming increasingly popular because of their environmental sustainability and lack of secondary pollutants. According to the kind of pollutant, the physicochemical properties of wastewater, and the algal species, algae and cyanobacteria can absorb and accumulate a wide spectrum of organic pollutants at different rates. In addition, phytoremediation is a cost-effective alternative to conventional treatments for degrading organic contaminants. Phycoremediationally produced algal biomass may also be an important part of the bioenergy value chain. This article focuses on microalgae and cyanobacteria species, which may remove many organic contaminants from water systems.

Suplementy diety – specyficzna żywność

Rynek suplementów diety rozwija się bardzo dynamicznie, co ma związek z rozpowszechnieniem tej kategorii produktów w środkach masowego przekazu, stosunkowo bezproblemową procedurą wprowadzenia na polski rynek oraz powszechną dostępnością (można je nabyć w aptece, sklepach zielarskich, spożywczych oraz w Internecie). Z definicji suplementy mają być uzupełnieniem diety, zaliczają się do żywności oraz nie mogą wykazywać działania leczniczego. Ich postać, która została ustawowo określona, może być wizualnie identyczna z postacią farmaceutyczną produktów leczniczych, co może wprowadzać konsumentów w błąd, jeżeli nie wiedzą, jak rozróżniać te dwie grupy. Polska legislacja nie uwzględnia żadnych wymogów dotyczących parametrów technologicznych czy właściwości fizycznych gotowych produktów. Na bezpieczeństwo stosowania suplementów diety, oprócz ich jakości i rzeczywistej zawartości deklarowanych składników, składa się również ewentualna obecność zanieczyszczeń i niedozwolonych substancji dodatkowych. Wybiórcza kontrola rynku oraz brak szczegółowych wytycznych dotyczących parametrów postaci suplementów daje znaczną dowolność producentom, jednocześnie umożliwia wprowadzenie na rynek produktów o wątpliwej jakości, które mogą zagrażać konsumentom, będąc całkowicie pozbawionymi działania prozdrowotnego. Ze względu na rosnące zainteresowanie tą grupą produktów przez konsumentów, przedstawiono w pracy sytuację prawną suplementów diety na polskim rynku, odnosząc się także do legislacji europejskiej i amerykańskiej. Omówiono procedurę wprowadzania na rynek, podstawowe wytyczne stawiane tej grupie produktów, wskazania do stosowania oraz aspekty związane z bezpieczeństwem i zagrożeniami wynikającymi ze stosowania suplementów diety.

Comprehensive detection of nitrated aromatic compounds in fine particulate matter using gas chromatography and tandem mass spectrometry coupled with an electron capture negative ionization source

Nitrated aromatic compounds (NACs) are toxic and allergenic airborne pollutants from both primary emissions and atmospheric reactions of aromatics with NO₂. A comprehensive investigation of NACs is challenging given their low ambient levels. By applying gas chromatography and tandem mass spectrometry coupled with an electron capture negative ionization source, this study achieved a comprehensive high-throughput and standard-independent detection of nonpolar NACs in fine particulate matter (PM_2.5) sampled over 2 years in Beijing, China. Overall, 1047 NACs were detected, among which, the elemental composition of 128 species were derived using time-of-flight mass spectrometry, and 25 species were confirmed using reference standards. In addition to mono-nitrated polycyclic aromatic hydrocarbons (NPAHs), di-nitrated PAHs and alkylated and oxygenated NPAHs were found. Cluster analysis suggested these compounds were derived from various sources particularly atmospheric reactions. We found that the annual levels of primary NPAHs decreased by 46.3-54.8% from 2012-2013 to 2016-2018, though the secondary species did not change significantly after normalization by PM_2.5. These results were validated by diagnostic ratios, which indicated an increasing contribution from the secondary formation including nighttime reactions. This novel method for NACs detection may provide valuable insights into the formation mechanisms of NACs in the atmosphere.

Validation of a high-throughput method for analysis of pesticide residues in hemp and hemp products

Hemp has been an agricultural commodity for millennia, and it has been undergoing a resurgence in interest and production due to its high content of cannabinoids, protein, fiber and other ingredients. For legal possession and use throughout the USA, hemp and hemp products must have delta-9-tetrahydrocannabinol (THC) concentration < 0.3%. As with most crops, pesticides may be applied when farming hemp, which need to be monitored in food, feed, and medicinal products. The aim of this work was to evaluate and validate the recently developed "quick, easy, cheap, effective, rugged, safe, efficient, and robust" (QuEChERSER) sample preparation mega-method to determine pesticide residues in hemp plants, flowers, powders, oils, and pellets. High-throughput analysis of final extracts for 106 targeted pesticides and metabolites from North American monitoring lists entailed: 1) ultrahigh-performance liquid chromatography - tandem mass spectrometry (UHPLC-MS/MS) with column back-flushing, and 2) instrument-top sample preparation + low-pressure gas chromatography (ITSP+LPGC-MS/MS). In QuEChERSER, 2 g sample is extracted with 10 mL 4/1 (v/v) acetonitrile/water by mechanical shaking for 10 min, followed by 3 min centrifugation. For LC, 0.2 mL of extract is taken and solvent exchanged into initial mobile phase followed by 5 min ultra-centrifugation prior to the 10 min analysis. For GC-amenable pesticides, the remaining initial extract is partitioned with 4/1 (w/w) anh. MgSO₄/NaCl, and 1 mL is taken for automated ITSP cleanup in parallel with 10 min LPGC analysis. In the former case, the UHPLC column is back-flushed with 1/1 (v/v) methanol/acetonitrile for 3 min between each injection to keep the system clean and avoid ghost peaks. Multi-level, multi-day validation results achieved 70-120% recoveries with RSDs < 20% for more than 80% of the analytes in hemp protein powder, oil, pellets, and fresh plant (dried hemp plant and flower were too complex). Limits of quantification (LOQs) were < 10 ng/g were achieved for nearly all pesticides, yielding 2.8% false negatives among >13,000 analyte results in the spiked samples. The QuEChERSER method was demonstrated to meet the challenge for several complex hemp matrices.

Analysis of ethoxyquin residues in animal feed using QuEChERS and gas chromatography tandem mass spectrometry and its results from Catalonian production 2018-2019

Ethoxyquin (EQ) is a quinolone commonly used as an antioxidant additive and a fungicide. However, Regulation (EU) 2017/962 suspended its authorisation as a feed additive for all animal species and categories. The aim of this study is thus to ensure compliance with this regulation by developing a method of analysing EQ in animal feed. For analysis, EQ was extracted from animal feed by using a modified QuEChERS protocol that used an ascorbic acid buffer to minimise its degradation. The extracts were analysed by gas chromatography coupled to triple quadrupole mass spectrometry (GC-QQQ), obtaining two chromatographic peaks corresponding to EQ and its transformation products. A study of these peaks was subsequently carried out using different standards, evincing that EQ had indeed been converted into several different transformation products. Quantification required the sum of the areas of the different peaks. The method was validated according to European Commission guidelines, namely SANTE/12682/2019. The obtainment of pesticide-free samples for carrying out the validation process was a critical achievement, as EQ residues were detected in 90% of the analysed samples. This was made possible by manufacturing 20 different feed samples from a mixture of several cereals used in animal feed in the laboratory. Method validation yielded excellent results in terms of accuracy (recoveries 70-120%), precision (RSD < 20%) and linearity (r²≥ 0.99) at the studied levels, as well as excellent sensitivity and selectivity (retention time ±0.1 min; ratio < 30%) to the LoQ. Over the course of 2018 and 2019, 70 samples of various feed matrices from agricultural production in Catalonia were analysed, garnering positive results 43% of the time.

Screening for More than 1,000 Pesticides and Environmental Contaminants in Cannabis by GC/Q-TOF

A method has been developed to screen cannabis extracts for more than 1,000 pesticides and environmental pollutants using a gas chromatograph coupled to a high-resolution accurate mass quadrupole time-of-flight mass spectrometer (GC/Q-TOF). An extraction procedure was developed using acetonitrile with solid phase extraction cleanup. Before analysis, extracts were diluted 125:1 with solvent. Two data mining approaches were used together with a retention-time-locked Personal Compound Database and Library (PCDL) containing high-resolution accurate mass spectra for pesticides and other environmental pollutants. (1) A Find-by-Fragments (FbF) software tool extracts several characteristic exact mass ions within a small retention time window where the compound elutes. For each compound in the PCDL, the software evaluates the peak shape and retention time of each ion as well as the monoisotopic exact mass, ion ratios, and other factors to decide if the compound is present or not. (2) A separate approach used Unknowns Analysis (UA) software with a peak-finding algorithm called SureMass to deconvolute peaks in the chromatogram. The accurate mass spectra were searched against the PCDL using spectral matching and retention time as filters. A subset PCDL was generated containing only pesticides that are most likely to be found on foods in the US. With about 250 compounds in the smaller PCDL, there were fewer hits for non-pesticides, and data review was much faster. Organically grown cannabis was used for method development. Twenty-one confiscated cannabis samples were analyzed and ten were found to have no detectable pesticides. The remaining 11 samples had at least one pesticide and one sample had seven detectable residues. Quantitative analysis was run on the confiscated samples for a subset of the pesticides found by screening. Two cannabis samples had residues of carbaryl and malathion that were estimated to be about 10 times greater than the highest US Environmental Protection Agency tolerance set for food and about 4,000 times greater than the Canadian maximum residue limits for dried cannabis flower.

Contaminants: a dark side of food supplements?

Food supplements (FS) are often consumed as one of the strategies to fight ageing-associated pathologies, especially in the case of oxidative stress-related diseases. Despite the popularity of FS, some concerns about their quality and safety have been raised, especially regarding the presence of contaminants. This paper reviews and discusses the occurrence of contaminants in marketed samples of FS in the last two decades, considering both scientific literature and notifications registered on RASFF portal. The most relevant classes of contaminants were included namely metals, toxins, pesticides, dioxins and PCBs, as well as pharmacologically active ingredients. Variable amounts of contaminants were reported in a significant number of commercially available FS. Although the presence of contaminants does not necessarily mean that their levels exceed the regulatory limits or that the FS intake constitutes a risk to human health, it alerts for the need to further monitor FS safety. The evaluation of the risk associated to the consumption of FS, especially in the elderly population, is particularly challenging due to the frequent exposure to multiple toxicants and to different exposure sources, as well as due to possible pre-existing diseases and respective therapeutics. Therefore, improved quality control procedures and monitoring programs should be pursued in order to avoid undesirable products and assure the safety of FS.

Identification and characterization of matrix components in spinach during QuEChERS sample preparation for pesticide residue analysis by LC-ESI-MS/MS, GC-MS and UPLC-DAD

In this article matrix components in spinach were investigated in detail. The samples were prepared using two QuEChERS (quick, easy, cheap, effective, rugged and safe) methods, AOAC and CEN. Liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS), gas chromatography-mass spectrometry (GC-MS) and ultra performance liquid chromatography-diode array detector (UPLC-DAD), were applied for component identification. The strategies of identification by LC-ESI-MS/MS include accurate mass spectra of the parent ion, comparison with previous literature data and investigation of the mass spectral decomposition pattern. Overall, fourteen components were identified by LC-ESI-MS/MS in each methods of AOAC and CEN, which were phytosteroids, flavonoids, fatty acids and fatty acid amides. Fifty components using AOAC method and fifty-seven components using CEN method were identified in GC-MS by comparing mass data with the National Institute of Standards and Technology (NIST, U.S.) database. The results indicate that the major components of the matrix are terpenoids, fatty acids and fatty acid esters. Moreover, three pigments (neoxanthin, violaxanthin and lutein) in the AOAC method and eight pigments (neoxanthin, violaxanthin, zeaxanthin, lutein, chlorophyll a, chlorophyll b, pheophytin a and beta-carotene) in the CEN method that gave a characteristics peak at 440 nm were identified by the UPLC-DAD. According to the sample preparation condition using different amounts of graphitized carbon black (GCB) in this study, the AOAC method had higher matrix component removal efficiency than the CEN method. A better understanding of matrix components would increase the current knowledge for improvement of existing QuEChERS methodology, as well as contribute to new method developments.

Fast determination of four polar contaminants in soy nutraceutical products by liquid chromatography coupled to tandem mass spectrometry

An analytical method based on a modified QuPPe (quick polar pesticide) extraction procedure coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was evaluated for the determination of four polar compounds (chlorate, fosetyl-Al, maleic hydrazide, and perchlorate) in nutraceutical products obtained from soy. Experimental conditions including extraction such as solvent, acidification, time, and clean-up sorbents were varied. Acidified acetonitrile (1 % formic acid, v/v) was used as extraction solvent instead of methanol (conventional QuPPe), which provides a doughy mixture which cannot be injected into the LC. Clean-up or derivatization steps were avoided. For analysis, several stationary phases were evaluated and Hypercarb (porous graphitic carbon) provided the best results. The optimized method was validated and recoveries ranged between 46 and 119 %, and correction factors can be used for quantification purposes bearing in mind that inter-day precision was equal to or lower than 17 %. Limits of quantification (LOQs) ranged from 4 to 100 μg kg-1. Soy-based nutraceutical products were analyzed and chlorate was detected in five samples at concentrations between 63 and 1642 μg kg-1. Graphical Abstract Analysis of polar compounds in soy-based nutraceutical products.

Analysis of Nitrosamines in Cooked Bacon by QuEChERS Sample Preparation and Gas Chromatography-Tandem Mass Spectrometry with Backflushing

Nitrites are added as a preservative to a variety of cured meats, including bacon, to kill bacteria, extend shelf life, and improve quality. During cooking, nitrites in the meat can be converted to carcinogenic nitrosamines (NAs), the formation of which is mitigated by the addition of antioxidants. In the past, the U.S. Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) monitored NAs in pan-fried bacon, but FSIS terminated monitoring of NAs in the 1990s due to the very low levels found. FSIS recently chose to conduct a risk assessment of NAs in cooked bacon to determine if current levels warrant routine monitoring of NAs again. To meet FSIS needs, we developed, validated, and implemented a new method of sample preparation and analysis to test cooked bacon for five NAs of most concern, which consist of N-nitroso-dimethylamine, -diethylamine, -dibutylamine, -piperidine, and -pyrrolidine. Sample preparation was based on the QuEChERS (quick, easy, cheap, effective, rugged, and safe) approach and analysis by gas chromatography-tandem mass spectrometry. Ruggedness was improved markedly in the analysis of the complex fatty extracts by backflushing the guard column, injection liner, and half of the analytical column after every injection. Validation results were acceptable with recoveries of 70-120% and <20% RSDs for the five NAs, with a reporting limit of 0.1 ng/g. NA concentrations in 48 samples were all <15 ng/g, with most <1 ng/g and many <0.1 ng/g. Also, microwave cooking of bacon gave slightly lower concentrations overall compared to pan-frying.

Multi-class methodology to determine pesticides and mycotoxins in green tea and royal jelly supplements by liquid chromatography coupled to Orbitrap high resolution mass spectrometry

A multi-class methodology was developed to determine pesticides and mycotoxins in food supplements. The extraction was performed using acetonitrile acidified with formic acid (1%, v/v). Different clean-up sorbents were tested, and the best results were obtained using C18 and zirconium oxide for green tea and royal jelly, respectively. The compounds were determined using ultra high performance liquid chromatography (UHPLC) coupled to Exactive-Orbitrap high resolution mass spectrometry (HRMS). The recovery rates obtained were between 70% and 120% for most of the compounds studied with a relative standard deviation <25%, at three different concentration levels. The calculated limits of quantification (LOQ) were <10 μg/kg. The method was applied to green tea (10) and royal jelly (8) samples. Nine (eight of green tea and one of royal jelly) samples were found to be positive for pesticides at concentrations ranging from 10.6 (cinosulfuron) to 47.9 μg/kg (paclobutrazol). The aflatoxin B1 (5.4 μg/kg) was also found in one of the green tea samples.

Evaluation of GC-ICP-MS/MS as a New Strategy for Specific Heteroatom Detection of Phosphorus, Sulfur, and Chlorine Determination in Foods

For the first time in the literature, application of a GC-ICP-MS/MS method for the selective and sensitive detection of specific heteroatoms of phosphorus, sulfur, and chlorine has been accomplished. As a proof of concept, organophosphorus, organosulfur, and organochlorine pesticides in various food matrices have been studied. For the detection of organophosphorus and organosulfur pesticides, oxygen was used in the collision reaction cell (CRC) to convert P (m/z 31) to PO(+) (m/z 47) and S (m/z 32) to SO(+) (m/z 48). Similarly, ClH2(+) (m/z 37) was monitored after the reaction of Cl (m/z 35) with hydrogen in the CRC for the determination of organochlorine pesticides. Real food samples (baby food purees, fresh vegetables, loose tea) were screened for their pesticide content, following preparation of triplicate extracts using QuEChERS (quick, easy, cheap, effective, rugged, and safe). Excellent linearity with correlation coefficients R ≥ 0.997 was achieved, and the lowest detection limits obtained for the organophosphorus, organosulfur, and organochlorine pesticides were 0.0005, 0.675, and 0.144 μg/kg, respectively.

Multifamily determination of pesticide residues in soya-based nutraceutical products by GC/MS-MS

An analytical method based on a modified QuEChERS extraction coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS) was evaluated for the determination of 177 pesticides in soya-based nutraceutical products. The QuEChERS method was optimised and different extraction solvents and clean-up approaches were tested, obtaining the most efficient conditions with a mixture of sorbents (PSA, C18, GBC and Zr-Sep(+)). Recoveries were evaluated at 10, 50 and 100 μg/kg and ranged between 70% and 120%. Precision was expressed as relative standard deviation (RSD), and it was evaluated for more than 160 pesticides as intra and inter-day precision, with values always below 20% and 25%, respectively. Limits of detection (LODs) ranged from 0.1 to 10 μg/kg, whereas limits of quantification (LOQs) from 0.5 to 20 μg/kg. The applicability of the method was proved by analysing soya-based nutraceuticals. Two pesticides were found in these samples, malathion and pyriproxyfen, at 11.1 and 1.5 μg/kg respectively.

Mass spectrometric analysis of pharmaceutical adulterants in products labeled as botanical dietary supplements or herbal remedies: a review

The increased availability and use of botanical dietary supplements and herbal remedies among consumers has been accompanied by an increased frequency of adulteration of these products with synthetic pharmaceuticals. Unscrupulous producers may add drugs and analogues of various classes, such as phosphodiesterase type 5 (PDE-5) inhibitors, weight loss, hypoglycemic, antihypertensive and anti-inflammatory agents, or anabolic steroids, to develop or intensify biological effects of dietary supplements or herbal remedies. The presence of such adulterated products in the marketplace is a worldwide problem and their consumption poses health risks to consumers. Analytical methods that allow rapid and reliable testing of dietary supplements for the presence of synthetic drugs are needed to address such fraudulent practices. Mass spectrometry (MS) and hyphenated techniques such as liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) have become primary tools in this endeavor. The present review critically assesses the role and summarizes the applications of MS in the analysis of pharmaceutical adulterants in botanical dietary supplements and herbal remedies. The uses of MS techniques in detection, confirmation, and quantification of known pharmaceutical adulterants as well as in screening for and structure elucidation of unexpected adulterants and novel designer drugs are discussed.

A method developed for determination of heptachlor and its metabolites from pork

A new method has been developed to determine heptachlor and its metabolites heptachlor-exo-epoxide and heptachlor-endo-epoxide in pork. The pork samples were extracted with acetone-n-hexane (2:8, V:V) and cleaned up by gel permeation chromatography and florisil solid-phase extraction cartridge. The extract was then determined by gas chromatography equipped with electron capture detector (GC-ECD), followed by validation using gas chromatography-mass spectrometry (GC-MS) with negative chemical ionization. Linearity of calibration curves ranged from 0.01 to 0.5 mg L(-1), with correlation coefficients of more than 0.9980 for GC-ECD and GC-MS, respectively. At spiked concentrations of 0.01, 0.05, and 0.1 mg kg(-1), the average recovery and relative standard deviation values were 87.1-102.2 and 4.0-11.3%, respectively. The limit of quantification for each analyte was 0.01 mg kg(-1), which satisfied the current maximum residue limit permitted in pork. Our results showed that the method developed was successfully used to determine heptachlor and heptachlor epoxide residues in real pork samples.

Comparison of QuEChERS official methodologies for the analysis of pesticide residues on Colombian fruit by GC-MS

Surveys of pesticide residues in fruit are important to demonstrate conformity with strict regulations of newly open markets for export of exotic fruit. Multi-residue methods are tools to ensure compliance with regulations and both the CEN and the AOAC have versions of QuEChERS that are used effectively as mainstream methods. The aim of this study was to assess their performance and pick the optimum one for this particular application using GC-MS. The use of graphitised carbon black (GCB) to improve clean-up was assessed. Optimisation of large volume injection (LVI) and implementation of concurrent back-flushing was needed in order to improve sensitivity at a low concentration levels for 33 pesticides (0.01 mg kg(-1)). Cleaner total ion current (TIC) profiles were obtained with the CEN method. Recoveries of most of the pesticides showed statistical differences (α = 0.05) when GCB was used in the AOAC method, unlike the CEN method. In general, GCB/no GCB use for CEN clean-up gave good, very similar results for all fruit, though some pesticides showed some adsorption on the GCB surface. The CEN general method was preferred since acceptable recoveries (> 80%) and RSD (< 20%) can be achieved for all analytes.

An integrated approach utilising chemometrics and GC/MS for classification of chamomile flowers, essential oils and commercial products

As part of an ongoing research program on authentication, safety and biological evaluation of phytochemicals and dietary supplements, an in-depth chemical investigation of different types of chamomile was performed. A collection of chamomile samples including authenticated plants, commercial products and essential oils was analysed by GC/MS. Twenty-seven authenticated plant samples representing three types of chamomile, viz. German chamomile, Roman chamomile and Juhua were analysed. This set of data was employed to construct a sample class prediction (SCP) model based on stepwise reduction of data dimensionality followed by principle component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The model was cross-validated with samples including authenticated plants and commercial products. The model demonstrated 100.0% accuracy for both recognition and prediction abilities. In addition, 35 commercial products and 11 essential oils purported to contain chamomile were subsequently predicted by the validated PLS-DA model. Furthermore, tentative identification of the marker compounds correlated with different types of chamomile was explored.