Fast multiresidue screening of 300 pesticides in water for human consumption by LC-MS/MS

Risk analysis for groundwater intakes based on the example of neonicotinoids

Neonicotinoids are a class of broad-spectrum insecticides that are dominant in the world market. They are widely distributed in the environment. Understanding the sources, distribution, and fate of these contaminants is critical to mitigating their effects and maintaining the health of aquatic ecosystems. Contamination of surface and groundwater by neonicotinoids has become a widespread problem worldwide, requiring comprehensive action to accurately determine the mechanisms behind the migration of these pesticides, their properties, and their adverse effects on the environment. A new approach to risk analysis for groundwater intake contamination with emerging contaminants was proposed. It was conducted on the example of four neonicotinoids (acetamiprid, clothianidin, thiamethoxam, and imidacloprid) in relation to groundwater accessed by a hypothetical groundwater intake, based on data obtained in laboratory tests using a dynamic method (column experiments). The results of the risk analysis conducted have shown that in this case study the use of acetamiprid and thiamethoxam for agricultural purposes poses an acceptable risk, and does not pose a risk to the quality of groundwater extracted from the intake for food purposes. Consequently, it does not pose a risk to the health and life of humans and other organisms depending on that water. The opposite situation is observed for clothianidin and imidacloprid, which pose a higher risk of groundwater contamination. For higher maximum concentration of neonicotinoids used in the risk analysis, the concentration of clothianidin and imidacloprid in the groundwater intake significantly (from several to several hundred thousand times) exceeds the maximum permissible levels for drinking water (<0.1 μg/L). This risk exists even if the insecticides containing these pesticides are used according to the information sheet provided by the manufacturer (lower maximum concentration), which results in exceeding the maximum permissible levels for drinking water from several to several hundred times.

A novel analytical approach for the determination of ethylene-thiourea and propylene-thiourea in vegetal foodstuffs by high-performance liquid chromatography hyphenated to inductively coupled plasma-tandem mass spectrometry

This study reports a novel analytical approach for the simultaneous determination of ethylene-thiourea (ETU) and propylene-thiourea (PTU) in fruits and vegetables by (reverse phase) high-performance liquid chromatography (HPLC) coupled to inductively coupled plasma-tandem mass spectrometry (ICP-QQQMS or ICP-MS/MS). A baseline separation of ETU and PTU was achieved in less than 5 min. A robust method validation by using the accuracy profile approach was performed by carrying out four measurement series in duplicate at six different levels over a timespan of 4 weeks (different days). The recovery factors ranged from 87 to 101% for ETU and from 98 to 99% for PTU (depending on the spiking level). The coefficient of variation in terms of repeatability (CVr) ranged from 1 to 4.7% for ETU and from 1.8 to 3.9% for PTU (depending also on the analyte level) while the coefficient of variation in terms of intermediate reproducibility (CVR) ranged from 3.4 to 10% for ETU and from 1.8 to 10.8% for PTU. The limit of quantification was 0.022 mg kg-1 (wet weight) for ETU and 0.010 mg kg-1 (ww) for PTU. This novel approach was proved to be highly robust and suitable for the determination of ETU and PTU in foodstuffs of vegetal origin.

Determination of 42 antibiotic residues in seven categories in water using large volume direct injection by ultra high performance liquid chromatography-triple quadrupole mass spectrometry

抗生素作为新型有机污染物在自然水体中被频繁检出,检出种类多且含量水平低,为了实现更加快速、全面、准确的高通量分析,研究开发了一种利用大体积直接进样测定水中7大类(磺胺类、林可酰胺类、喹诺酮类、大环内酯类、四环素类、头孢类及氯霉素类)42种抗生素的超高效液相色谱-三重四极杆质谱法。水样经0.22 μm滤膜过滤,加入Na₂EDTA并调节pH值至6.0~8.0,加入内标混匀后,采用Phenomenex Kinetex C18柱(50 mm×30 mm, 2.6 μm),以0.1%(v/v)甲酸水溶液-乙腈作为流动相进行梯度洗脱,质谱智能化分时间段-多反应选择离子监测(Schedule-MRM)模式进行检测。42种抗生素在相关线性范围内线性良好(r=0.9949~0.9995),回收率为80.1%~125%,相对标准偏差为0.8%~12.2%,方法检出限为0.015~3.561 ng/L。将该方法应用于10份水源水和5份末梢水的检测,结果显示在42种抗生素中,12种抗生素有检出,包括磺胺类、大环内酯类、林可酰胺类和氯霉素类,其在水源水中的检出率达100%;林可霉素和氯霉素是检出质量浓度最高的两种抗生素,它们的质量浓度范围分别为3.83~13.8和24.8~33.6 ng/L。该方法从检出限和回收率两方面与标准方法和文献报道进行了比较,检出限及回收率均满足要求。该方法与传统前处理方法相比具有简单、快速、绿色、精密度高、准确度高、消耗样品量小的优点,能用于地表水、地下水、末梢水等较为洁净水体中42种痕量水平的抗生素测定。

An Alternative Strategy for Screening and Confirmation of 330 Pesticides in Ground- and Surface Water Using Liquid Chromatography Tandem Mass Spectrometry

The presence of pesticide residues in water is a huge worldwide concern. In this paper we described the development and validation of a new liquid chromatography tandem mass spectrometric (LC-MS/MS) method for both screening and quantification of pesticides in water samples. In the sample preparation stage, the samples were buffered to pH 7.0 and pre-concentrated on polymeric-based cartridges via solid-phase extraction (SPE). Highly sensitive detection was carried out with mobile phases containing only 5 mM ammonium formate (pH of 6.8) as an eluent additive and using only positive ionization mode in MS/MS instrument. Hence, only 200-fold sample enrichment was required to set a screening detection limit (SDL) and reporting limit (RL) of 10 ng/L. The confirmatory method was validated at 10 and 100 ng/L spiking levels. The apparent recoveries obtained from the matrix-matched calibration (5–500 ng/L) were within the acceptable range (60–120%), also the precision (relative standard deviation, RSD) was not higher than 20%. During the development, 480 pesticides were tested and 330 compounds fulfilled the requirements of validation. The method was successfully applied to proficiency test samples to evaluate its accuracy. Moreover, the method robustness test was carried out using higher sample volume (500 mL) followed by automated SPE enrichment. Finally, the method was used to analyze 20 real samples, in which some compounds were detected around 10 ng/L, but never exceeded the assay maximum level.

Presence, behaviour and removal of selected organic micropollutants through drinking water treatment

This paper investigates the occurrence and removal of 60 organic micropollutants (OMPs) including pharmaceuticals, personal care products, pesticides and per- and polyfluoroalkyl substances in a drinking water treatment plant (DWTP) treating raw water from the Ebro River (NE Spain). The behaviour of the OMPs was evaluated in each treatment: pre-ozonation, flocculation-coagulation-decantation-sand filtration, post-ozonation and granular activated carbon filtration. Thirty-one of the sixty OMPs studied were detected in source water with individual median concentrations below 10 ng L^-1 for all the compounds except for caffeine (64.1 ng L^-1). The highest concentration peaks in the source water were found for caffeine (124.5 ng L^-1), terbuthylazine (52.0 ng L^-1), imidacloprid (30.2 ng L^-1) and paracetamol (25.6 ng L^-1). Of the 31 compounds detected in the source water, 17 were also detected in the finished drinking water. Of these 17 compounds, 10 were PFASs, which indicated that this group of compounds had not been effectively removed throughout the drinking water treatments. The overall removal efficiencies of OMPs in the DWTP ranged from -50.9% to 100%. The most efficient removal technologies were ozonation and granular activated carbon.

Inclusion of Pesticide Transformation Products Is Key to Estimating Pesticide Exposures and Effects in Small U.S. Streams

Improved analytical methods can quantify hundreds of pesticide transformation products (TPs), but understanding of TP occurrence and potential toxicity in aquatic ecosystems remains limited. We quantified 108 parent pesticides and 116 TPs in more than 3 700 samples from 442 small streams in mostly urban basins across five major regions of the United States. TPs were detected nearly as frequently as parents (90 and 95% of streams, respectively); 102 TPs were detected at least once and 28 were detected in >20% samples in at least one region-TPs of 9 herbicides, 2 fungicides (chlorothalonil and thiophanate-methyl), and 1 insecticide (fipronil) were the most frequently detected. TPs occurred commonly during baseflow conditions, indicating chronic environmental TP exposures to aquatic organisms and the likely importance of groundwater as a TP source. Hazard quotients based on acute aquatic-life benchmarks for invertebrates and nonvascular plants and vertebrate-centric molecular endpoints (sublethal effects) quantify the range of the potential contribution of TPs to environmental risk and highlight several TP exposure-response data gaps. A precautionary approach using equimolar substitution of parent benchmarks or endpoints for missing TP benchmarks indicates that potential aquatic effects of pesticide TPs could be underestimated by an order of magnitude or more.

Simultaneous determination and dietary risk assessment of clethodim and its metabolites in different fruits and vegetables

Clethodim is one of the most widely used herbicides in agriculture and, after field application, is metabolised to several metabolites. The potential toxicological negative effects of these compounds are poorly understood. Thus, recently, within the risk assessment framework, the European Food Safety Authority (EFSA) proposed to include the minor metabolites in the definition of clethodim residue. In this work, an easy to use and reliable UHPLC method coupled with a triple quadrupole MS/MS was developed and validated for the detection and quantification of the herbicide clethodim and related metabolites clethodim sulphone, clethodim sulphoxide, metabolites M17R and M18R in apple, grape, olive and rice. The five analytes were extracted by using a modified QuEChERS procedure, while the active ingredients were determined in multiple reaction monitoring (MRM) ion-switching mode. The proposed method showed calibration curve linearity with r² ≥ 0.990 for all active ingredients (a.is.) both in solvent and matrix extracts. Limits of quantitation (LOQ) of the five compounds ranged from 9.44 µg/kg for M17R in olive extract to 11.01 µg/kg for clethodim in apple extract. Recoveries values ranged from 86% to 119% at two concentration levels (LOQ and 10xLOQ), while the intraday and interday precisions of the method were both below 10% in all cases. The method was successfully used for the quantification of the five a.is. in different food matrices. Furthermore, chronic dietary risk was investigated using a hazard quotients (HQ) method based on European dietary habits. The chronic dietary exposure risk quotients ranged from 1.0 × 10^-5 (lower bound scenario) to 2.7 × 10^-4 (upper bound scenario) which were significantly lower than 1. Data obtained indicate that the dietary exposure risks were acceptable for clethodim and its major and minor metabolites applied in apple, table grape, rice and table olive.

New Trend in the Extraction of Pesticides from the Environmental and Food Samples Applying Microextraction Based Green Chemistry Scenario: A Review

This review focused on the green microextraction methods used for the extraction of pesticides from the environmental and food samples. Microextraction techniques have been explored and applied in various fields of analytical chemistry since its beginning, as evinced by the numerous reviews published. The success of any technique in science and technology is measured by the simplicity, environmentally friendly, and its applications; and the microextraction technique is highly successive. Deliberations were attentive to studies where efforts have been made to validate the methods through the inter-laboratory comparison study to assess the analytical performance of microextraction techniques against conventional methods. Succinctly, developed microextraction methods are shown to impart significant benefits over conventional techniques. Provided that the analytical community continues to put forward attention and resources into the growth and validation of the microextraction technique, a promising future for microextraction is forecasted.

Comparison of preconcentration methods for nontargeted analysis of natural waters using HPLC-HRMS: Large volume injection versus solid-phase extraction

Nontargeted analysis of water samples using liquid chromatography combined with high‐resolution mass spectrometers is an emerging approach for surface water monitoring and evaluation of water treatment processes. In this study, sample preconcentration via direct, large volume injection with 500 μL and 1000 μL injection volumes was compared to SPE regarding analytical performance parameters in targeted and nontargeted workflows. In targeted analysis, the methods were evaluated in terms of LOD and intrabatch precision of the selected compounds, whereas in nontargeted analysis, the number of detected unknown compounds, the method's intra‐batch precision, and the retention time versus molecular mass pattern of the detected unknowns were evaluated. In addition, a novel intensity drift correction method was developed that is not based on quality control samples and makes use of the signals obtained for continuously infused reference compounds, which are conventionally utilized for online mass drift correction. It could be demonstrated that the new correction method significantly reduced the bias introduced by instrumental drift and is important for the reliable intercomparison of different nontargeted methods. Intercomparison of results showed that the 1000 μL large volume injection method revealed the best performance in terms of precision under repeatability conditions of measurement as well as lower LODs for targeted compound analysis. In nontargeted analysis, the SPE method detected a higher number of unknown compounds but exhibited also a higher uncertainty of measurement caused by matrix effects.

High-throughput multi-residue quantification of contaminants of emerging concern in wastewaters enabled using direct injection liquid chromatography-tandem mass spectrometry

A rapid quantitative method for 135 contaminants of emerging concern (CECs) in untreated wastewater enabled with direct injection liquid chromatography-tandem mass spectrometry is presented. All compounds were analysed within 5 min on a short biphenyl cartridge using only 10 μL of filtered sample per injection. Up to 76 compounds were monitored simultaneously during the gradient (including mostly two transitions per compound and stable isotope-labelled analogues) while yielding >10 data points per peak. Evaluation of seven solid phase extraction sorbents showed no advantage for wastewater matrix removal. Excellent linearity, range, accuracy and precision was achieved for most compounds. Matrix effects were <11 % and detection limits were <30 ng L^-1 on average. Application to untreated wastewater samples from three wastewater treatment works in the UK, USA and Mexico, enabled quantification of 56 compounds. Banned and EU 'watch-list' substances are critically discussed, including pesticides, macrolide antibiotics, diclofenac, illicit drugs as well as multiple pharmaceuticals and biocides. This high-throughput method sets a new standard for the speedy and confident determination of over a hundred CECs in wastewater at the part-per-trillion level, as demonstrated by performing over 260 injections per day.

A liquid chromatography-tandem mass spectrometry method to simultaneously determinate dichlorvos and phoxim in tobacco

A simple pretreatment method with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated to simultaneously determine dichlorvos and phoxim in tobacco and soil matrices. Satisfactory linearity (R2  ≥ 0.9991) of the method was obtained for both analytes. The limits of detection and limits of quantification for dichlorvos and phoxim in three matrices were 0.0015-0.006 and 0.005-0.02 mg/kg, respectively. Average recoveries were 78.24-92.21% for dichlorvos and 76.62-100.51% for phoxim in soil, green tobacco leaves and cured tobacco leaves. The intra- and inter-day relative standard deviations were <6%. The established method was successfully applied for the residual analysis of dichlorvos and phoxim in real soil and tobacco samples. The results indicated that the established method could be used to detect trace amounts of dichlorvos and phoxim in tobacco. The data could also help the Chinese government establish maximum residue limits of dichlorvos and phoxim on tobacco and establish proper and safe use of dichlorvos and phoxim on tobacco plants in China.

A simple, fast method for the analysis of 20 contaminants of emerging concern in river water using large-volume direct injection liquid chromatography-tandem mass spectrometry

A fast and sensitive method for the determination of a structurally and physico-chemically diverse group of contaminants of emerging concern (CEC) based on large-volume direct injection liquid chromatography-tandem mass spectrometry was developed. The method can be used to determine 20 CECs belonging to different pollutant families (pharmaceuticals, personal care products, and pesticides) in river water at nanogram per liter. A single analytical run is required and the positive and negative ionization modes can be used simultaneously. Because of the large-volume injections of samples and the high sensitivity of the current mass spectrometers, the method has no need of a preconcentration step. The analytes are quantitated with matrix-matched calibration curves. The estimated limits of detection were in the range 0.1-5 ng L^-1. The accuracy of the method was in the range 86-114%, and the precision, expressed as a relative standard deviation (RSD %), was below 18% for all the analytes (n = 5, at 5, 10, and 25 ng L^-1). The method was applied to water samples taken from different points along the lower course of the Ebro River, Spain. A total of 12 out of the 20 target analytes were detected, and the ones at higher concentrations were caffeine and the pharmaceuticals paracetamol and ibuprofen (184.8 ng L^-1, 63.3 ng L^-1, and 23.3 ng L^-1, respectively).

Enantioselective analysis and degradation of isofenphos-methyl in vegetables by liquid chromatography-tandem mass spectrometry

The enantioselective degradation of isofenphos-methyl in cowpea, cucumber, and pepper under field conditions was investigated to elucidate the enantioselective environmental behaviors of this pesticide. The concentrations of the enantiomers were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The degradation rates of isofenphos-methyl enantiomers were the fastest in cowpea, followed by cucumber and pepper, with half-lives ranging from 1.48 to 8.06 days. The enantioselective degradation of isofenphos-methyl was characterized by calculating and comparing the values of enantiomer fraction (EF) and enantiomeric selectivity (ES). The degradation rates and enantioselectivities of isofenphos-methyl were different for the three vegetables. (R)-(-)-isofenphos-methyl was degraded faster than (S)-(+)-isofenphos-methyl in cowpea and cucumber, whereas (S)-(+)-isofenphos-methyl underwent preferential degradation in pepper. These results could serve as a reference for the study of enantioselective behavior of isofenphos-methyl in plants and further food safety evaluation, where the enantiomeric differences should be considered in the risk assessment.

Simultaneous determination and method validation of clethodim and its metabolites clethodim sulfoxide and clethodim sulfone in tobacco by LC-MS/MS

A simple method was developed and validated for the simultaneous determination of clethodim, clethodim sulfoxide, and clethodim sulfone in soil and tobacco by liquid chromatography with tandem mass spectrometry. The three target compounds were extracted from tobacco and soil with acetonitrile, and the extracts were purified using octadecyl silane. The proposed method showed satisfactory linearity (R2 ≥ 0.9973) for the target compounds. The limits of detection and quantitation of the three analytes in all matrices were 0.024-0.06 and 0.08-0.2 mg/kg, respectively. The recovery was tested in blank soil and tobacco leaf samples and calculated to be 74.8-104.4% with relative standard deviations of 1.9-12.1%. The developed method was successfully applied to the analysis of residues of clethodim, clethodim sulfoxide and clethodim sulfone in real soil and tobacco samples. The results indicated that the developed method can meet the requirements for the analysis of trace amounts of all three analytes in soil and tobacco.

Kinetics and Mechanism of Degradation of Aqueous Promecarb Insecticide Studied by UV Spectrophotometry and HPLC

The present paper deals with the degradation mechanism of the insecticide promecarb, or 3-isopropyl-5-methylphenyl- N-methylcarbamate, in aqueous media. The reaction kinetics have been investigated using UV spectrophotometry and reversed phase HPLC. The determination of 3-isopropyl-5-methylphenol as the main product of promecarb hydrolysis gives evidence for the significant reactivity of this insecticide in alkaline solution. The rate constants were determined following a proposed first-order kinetic model. The positive activation entropy obtained Δ S≠ = +66.82 J mol−1 K−1 and the absence of general basic catalysis indicates an E1cB mechanism involving unimolecular collapse of the promecarb via a methylisocyanate intermediate. These results were confirmed by the fact that promecarb fits well into Brønsted and Hammett plots obtained for a series of substituted N-methylcarbamates for which the decomposition in aqueous media was established to follow an E1cB mechanism.

Assessment of quinoxyfen phototransformation pathways by liquid chromatography coupled to accurate mass spectrometry

Quinoxyfen has been recently identified as a priority hazardous substance in the field of the European water policy. In this work, its fate in aqueous samples and solid supports under UV and solar radiation is investigated. Diverse degradation experiments were carried out, at lab scale, using spiked aliquots of different aqueous matrices (ultrapure, treated wastewater and river water) irradiated at different wavelengths (λ = 254 nm, λ = 365 nm and solar light). Half-lives of quinoxyfen (2-26 min) depended on the wavelength and the intensity of radiation whilst the nature of the aqueous matrix did not play an important role in degradation kinetics. Moreover, experiments under solar radiation of doped silicone tubes were performed to simulate degradation when quinoxyfen is adsorbed on plant leaves or soil. As the compound is not completely mineralized, the identification of quinoxyfen transformation products (TPs) was performed by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) injection of different irradiated time aliquots. The full-fragment ion spectra, at different collision energies, allowed the elucidation of the chemical structure of TPs formed by hydroxylation, cyclization or cleavage reactions. Five out of seven identified TPs have not been reported previously. The ecotoxicity simulation by software (TEST and ECOSAR) for TPs revealed that some of them could cause harmful effects to organisms such as Daphnia magna or Fathead minnow in a similar extent to the precursor; moreover, the time course profiles of major TPs (TP1 and TP2) revealed a much higher resistance to further photodegradation than quinoxyfen. Graphical abstract Quinoxyfen phototransformation pathways.

Development of a Photoinduced Chemiluminescent Method for the Determination of the Herbicide Quinmerac in Water

A new, simple, and sensitive method, based on photoinduced chemiluminescence, was developed for the determination of quinmerac. The photoproduct, obtained after ultraviolet irradiation in basic medium, was mixed with sodium sulfite (sensitizer), and Ce(IV) (oxidant) in acid medium. A wide linear dynamic range (2-600 ng mL(-1)) and a limit of detection of 0.6 ng mL(-1) were obtained without any pretreatment (0.08 ng mL(-1) after solid-phase extraction). The determination was performed using a flow-injection manifold, which allowed a high throughput (144 h(-1)). The interday reproducibility was 5.6% (n = 5), and the intraday repeatability was 3.9 and 2.9% for 20 and 200 ng mL(-1) of quinmerac, respectively (n = 21). Finally, the method was applied to surface water and groundwater, with recoveries ranging from 78.1 to 94.5%.

Travelling-wave ion mobility time-of-flight mass spectrometry as an alternative strategy for screening of multi-class pesticides in fruits and vegetables

This paper reports a novel approach to screening multi-class pesticides by ion mobility time-of-flight mass spectrometry detection. Nitrogen was selected as mobility gas. After optimization of the different ion mobility parameters, determination of matrix effect on the drift times was conducted using different matrix extracts. The results showed that drift time values are not influenced by the matrix and also are independent of the concentration within the working range for 100 pesticides tested, making drift time a powerful additional identification tool. Based on statistics, 2% variation criteria provides a good fit for all the pesticides targeted, and could be considered as a maximum acceptable criteria associated with the drift time parameter for identification purpose. This 2% value is in agreement with already reported criteria, for instance, for GC or LC retention time in European documents. Finally, the well-known feature of mobility to separate complex mixtures was also tested to obtain purified extracted mass spectra of pesticides present in fruit extract.

Multi-residue method for the determination of over 400 priority and emerging pollutants in water and wastewater by solid-phase extraction and liquid chromatography-time-of-flight mass spectrometry

This article describes the development and validation of a liquid chromatography high-resolution mass spectrometry method for the simultaneous determination of over 400 multi-class priority and emerging pollutants with different physicochemical properties in environmental waters (surface water and wastewater). The proposed approach is based on the use of a database consisting of retention time/exact mass (of selected ions) pairs implemented with specific software for data analysis. The targeted list comprises 430 contaminants belonging to different compound categories, including 105 multiclass pharmaceuticals (analgesics/anti-inflammatories, antibiotics, lipid regulators, β-blockers, antiepileptic/psychiatrics ulcer healings, diuretics, hormones and bronchodilatadors), life-style products (caffeine, nicotine), 21 drugs of abuse and their metabolites, 279 pesticides and some of their more relevant metabolites, nitrosamines, flame retardants, plasticizers and perfluorinated compounds. The proposed approach included a simple offline solid phase extraction (SPE) step using polymeric cartridges (Oasis HLB) with 200mL of water sample loaded, followed by analysis by rapid resolution liquid chromatography electrospray time-of-flight mass spectrometry (LC-TOFMS) in both positive and negative modes. The identification of the positive findings is accomplished with the data from accurate masses of the target ions along with retention time data and characteristic in-source fragment ions. The overall method performance was satisfactory with limits of quantification lower than 10ngL(-1) for the 44% of studied compounds. Recoveries between 50% and 130% were obtained for the 65% of the analytes (281 compounds). Matrix effects occurring with wastewater matrices were also assessed. The developed method was applied to the determination of target analytes in real surface water and wastewater samples.

Factors affecting the quality of bottled water

The ever-increasing popularity of bottled water means that it is important to analyze not only its mineral content but also, above all, its content of possible contaminants, especially the organic ones. In this respect, bottled waters are a special case, because apart from organic chemical contaminants derived from the well from which they were acquired, their secondary contamination is always possible, during treatment or storage or transport in unsuitable conditions (sunlight and elevated temperature). This paper describes how various factors, from the area around the well, and the method of drawing and treating water, to the manner in which the finished product is stored and transported may affect the quality of bottled waters. It also summarizes literature information on the levels of organic contaminants in various kinds of bottled water samples.

Use of time-of-flight mass spectrometry for large screening of organic pollutants in surface waters and soils from a rice production area in Colombia

The irrigate district of Usosaldaña, an important agricultural area in Colombia mainly devoted to rice crop production, is subjected to an intensive use of pesticides. Monitoring these compounds is necessary to know the impact of phytosanitary products in the different environmental compartments. In this work, surface water and soil samples from different sites of this area have been analyzed by applying an analytical methodology for large screening based on the use of time-of-flight mass spectrometry (TOF MS) hyphenated to liquid chromatography (LC) and gas chromatography (GC). Several pesticides were detected and unequivocally identified, such as the herbicides atrazine, diuron or clomazone. Some of their main metabolites and/or transformation products (TPs) like deethylatrazine (DEA), deisopropylatrazine (DIA) and 3,4-dichloroaniline were also identified in the samples. Among fungicides, carbendazim, azoxystrobin, propiconazole and epoxiconazole were the most frequently detected. Insecticides such as thiacloprid, or p,p'-DDT metabolites (p,p'-DDD and p,p'-DDE) were also found. Thanks to the accurate-mass full-spectrum acquisition in TOF MS it was feasible to widen the number of compounds to be investigated to other families of contaminants. This allowed the detection of emerging contaminants, such as the antioxidant 3,5-di-tertbutyl-4-hydroxy-toluene (BHT), its metabolite 3,5-di-tert-butyl-4-hydroxy-benzaldehyde (BHT-CHO), or the solar filter benzophenone, among others.

Dissipation and residues of flutriafol in wheat and soil under field conditions

The dissipation and residues of flutriafol in wheat and soil under field conditions in Beijing, Anhui and Shandong in China were determined based on high performance liquid chromatography. Flutriafol were extracted with acetonitrile and cleaned up by solid-phase extraction with florisil cartridges before UV detection. The limits of detection and quantification of flutriafol were 0.04 ng and 0.01 mg/kg for both wheat and soil samples, respectively. The mean recoveries ranged from 93.4% to 96.4%, with relative standard deviation between 3.8% and 6.8% at three spiked levels (0.01, 0.1, 1.0 mg/kg). Half-lives were 13.3, 9.9 and 13.6 days in soil, while 15.2, 10.8 and 9.2 days in wheat plant in Beijing, Anhui and Shandong, respectively. The terminal residues of flutriafol were below the maximum residue limit 0.02 mg/kg set by Japan in wheat when pre-harvest interval were 35 days.

Comparison of the selectivity of different sorbent phases for bar adsorptive microextraction--application to trace level analysis of fungicides in real matrices

Bar adsorptive micro-extraction combined with liquid desorption followed by large volume injection-gas chromatography-mass spectrometry operating in the selected-ion monitoring acquisition mode (BAμE-LD/LVI-GC-MS(SIM)) was developed for the determination of trace levels of ten fungicides (azoxystrobin, difenoconazole, metalaxyl-M, myclobutanil, penconazole, tebuconazole, flusilazole, cyprodinil, procymidone and benalaxyl) in aqueous matrices. By comparing different sorbent coatings (two activated carbons, two styrene-divinylbenzene and one modified pyrrolidone polymers) through BAμE, the latter phase showed much higher selectivity and capacity offering multiple mechanisms of interaction, even against polydimethylsiloxane by stir bar sorptive extraction. Assays performed on 25 mL of water samples spiked at the 0.8 μg/L level, yielded recoveries ranging from 100.0 to 107.8%, under optimized experimental conditions; BAμE(modified pyrrolidone) - equilibrium time: 4h (1000 rpm), pH 5.5; LD - solvent:methanol/acetonitrile (1/1), 15 min with sonification. The analytical performance showed convenient detection limits (4.0-30.0 ng/L) and excellent linear dynamic ranges (0.04-1.60 μg/L) with remarkable correlation coefficients (r(2)>0.9980). Excellent repeatability was also achieved through intraday (RSD<13.7%) and interday (RSD<9.9%) assays. By using the standard addition methodology, the application of the present analytical approach on tap and ground water, as well as, wine samples revealed good sensitivity and absence of matrix effects. The proposed method operating under floating sampling technology proved to be a suitable sorption-based static microextraction alternative to monitor fungicides in real matrices, showing to be easy to implement, reliable, sensitive, requiring low sample volume and the possibility to choose the most selective sorbent coating according to the targets of interest.

Development of a broad-specificity monoclonal antibody-based immunoaffinity chromatography cleanup for organophosphorus pesticide determination in environmental samples

An immunoaffinity chromatographic (IAC) method for the selective extraction and concentration of 13 organophosphorus pesticides (OPs, including coumaphos, parathion, phoxim, quinalphos, dichlofenthion, triazophos, azinphos-ethyl, phosalone, isochlorthion, parathion-methyl, cyanophos, disulfoton, and phorate) prior to analysis by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed. The IAC column was prepared by covalently immobilizing a monoclonal antibody with broad specificity for OPs on CNBr-activated Sephrose 4B. The column capacity ranged from 884 to 2641 ng/mL of gel. The optimum elution solvent was 0.01 M phosphate-buffered saline containing 80% methanol. The breakthrough volume of the IAC column was found to be 400 mL. Recoveries of OPs from spiked environmental samples by IAC cleanup and HPLC-MS/MS analysis ranged from 60.2 to 107.1%, with a relative standard deviation below 11.1%. The limit of quantitation for 13 OPs ranged from 0.01 to 0.13 ng/mL (ng/g). The application of IAC cleanup coupled to HPLC-MS/MS in real environmental samples demonstrated the potential of this method for the determination of OP residues in environmental samples at trace levels.

Green aspects of techniques for the determination of currently used pesticides in environmental samples

Pesticides are among the most dangerous environmental pollutants because of their stability, mobility and long-term effects on living organisms. Their presence in the environment is a particular danger. It is therefore crucial to monitor pesticide residues using all available analytical methods. The analysis of environmental samples for the presence of pesticides is very difficult: the processes involved in sample preparation are labor-intensive and time-consuming. To date, it has been standard practice to use large quantities of organic solvents in the sample preparation process; but as these solvents are themselves hazardous, solvent-less and solvent-minimized techniques are becoming popular. The application of Green Chemistry principles to sample preparation is primarily leading to the miniaturization of procedures and the use of solvent-less techniques, and these are discussed in the paper.

The pivotal role of mass spectrometry in determining the presence of chemical contaminants in food raw materials

During recent years, a rising interest from consumers and various governmental organizations towards the quality of food has continuously been observed. Human intervention across the different stages of the food supply chain can lead to the presence of several types of chemical contaminants in food-based products. On a normal daily consumption basis, some of these chemicals are not harmful; however, for those that present a risk to consumers, legislation rules were established to specify tolerance levels or in some cases the total forbiddance of these specific contaminants. Hence, the use of appropriate analytical tools is recommended to properly identify chemical contaminants. In that context, mass spectrometry (MS)-based techniques coupled or not to chromatography offer a vast panel of features such as sensitivity, selectivity, quantification at trace levels, and/or structural elucidation. Because of the complexity of food-based matrices, sample preparation is a crucial step before final detection. In the present manuscript, we review the contribution and the potentialities of MS-based techniques to ensure the absence of chemical contaminants in food-based products.

Direct sampling and analysis from solid-phase extraction cards using an automated liquid extraction surface analysis nanoelectrospray mass spectrometry system

Direct liquid extraction based surface sampling, a technique previously demonstrated with continuous flow and autonomous pipette liquid microjunction surface sampling probes, has recently been implemented as a liquid extraction surface analysis (LESA) mode on a commercially available chip-based infusion nanoelectrospray ionization (nanoESI) system. In the present paper, the LESA mode was applied to the analysis of 96-well format custom-made solid-phase extraction (SPE) cards, with each well consisting of either a 1 or a 2 mm diameter monolithic hydrophobic stationary phase. These substrate wells were conditioned, loaded with either single or multi-component aqueous mixtures, and read out using the commercial nanoESI system coupled to a hybrid triple quadrupole/linear ion trap mass spectrometer or a linear ion trap mass spectrometer. The extraction conditions, including extraction/nanoESI solvent composition, volume, and dwell times, were optimized in the analysis of targeted compounds. Limit of detection and quantitation as well as analysis reproducibility figures of merit were measured. Calibration data was obtained for propranolol using a deuterated internal standard which demonstrated linearity and reproducibility. A 10× increase in signal and cleanup of micromolar angiotensin II from a concentrated salt solution was demonstrated. In addition, a multicomponent herbicide mixture at ppb concentration levels was analyzed using MS(3) spectra for compound identification in the presence of isobaric interferences.

Current mass spectrometry strategies for the analysis of pesticides and their metabolites in food and water matrices

Analysis of pesticides and their metabolites in food and water matrices continues to be an active research area closely related to food safety and environmental issues. This review discusses the most widely applied mass spectrometric (MS) approaches to pesticide residues analysis over the last few years. The main techniques for sample preparation remain solvent extraction and solid-phase extraction. The QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) approach is being increasingly used for the development of multi-class pesticide residues methods in various sample matrices. MS detectors-triple quadrupole (QqQ), ion-trap (IT), quadrupole linear ion trap (QqLIT), time-of-flight (TOF), and quadrupole time-of-flight (QqTOF)-have been established as powerful analytical tools sharing a primary role in the detection/quantification and/or identification/confirmation of pesticides and their metabolites. Recent developments in analytical instrumentation have enabled coupling of ultra-performance liquid chromatography (UPLC) and fast gas chromatography (GC) with MS detectors, and faster analysis for a greater number of pesticides. The newly developed "ambient-ionization" MS techniques (e.g., desorption electrospray ionization, DESI, and direct analysis in real time, DART) hyphenated with high-resolution MS platforms without liquid chromatography separation, and sometimes with minimum pre-treatment, have shown potential for pesticide residue screening. The recently introduced Orbitrap mass spectrometers can provide high resolving power and mass accuracy, to tackle complex analytical problems involved in pesticide residue analysis.

QuEChERS multiresidue method validation and mass spectrometric assessment for the novel anthranilic diamide insecticides chlorantraniliprole and cyantraniliprole

The gas-phase dissociation reactions of chlorantraniliprole (Rynaxypyr) and cyantraniliprole (Cyazypyr) have been studied in triple-quadrupole, ion trap, and orbitrap mass spectrometers equipped with electrospray and desorption electrospray ion sources, revealing the formation of odd-electron fragment ions, the structures of which were elucidated. The odd-electron fragments were unusually abundant, and their formation is proposed to occur via a tricyclic intermediate. The applicability of the QuEChERS multiresidue method for the quantitation of chlorantraniliprole and cyantraniliprole was also assessed in this study. Four matrices representative of oily, watery, acidic, and dry crop groups were tested, with a targeted limit of quantitation (LOQ) of 0.01 mg/kg. Average recoveries ranged between 87 and 107%, with relative standard deviations (RSD) of ≤ 8%. Linear calibration functions with correlation coefficients r > 0.99 were obtained. The study provides an expansion of the QuEChERS method to include anthranilic diamides and a mass spectrometric assessment for these two novel agrochemical active ingredients.

Environmental and food analysis by desorption atmospheric pressure photoionization-mass spectrometry

Desorption atmospheric pressure photoionization-mass spectrometry (DAPPI-MS) is a versatile surface analysis technique for a wide range of analytes, especially for neutral and non-polar analytes. Here, a set of analytes typically found in environmental or food samples was analyzed by DAPPI-MS. The set included five polyaromatic hydrocarbons (PAHs), one N-PAH, one brominated flame retardant, and nine pesticides, which were studied with three different spray solvents: acetone and toluene in positive ion mode, and anisole in negative ion mode. The analytes showed [M + H](+), M(+*), and [M-H](-) ions as well as fragmentation and substitution products. Detection limits for the studied compounds ranged from 30 pg to 1 ng (from 0.14 to 5.6 pmol). To demonstrate the feasibility of the use of DAPPI-MS two authentic samples - a circuit board and orange peel - and a spiked soil sample were analyzed. Tetrabromobisphenol A, imazalil, and PAHs were observed from the three above-mentioned samples, respectively. The method is best suited for rapid screening analysis of environmental or food samples.