Unified Method for Target and Non-Target Monitoring of Pesticide Residues in Fruits and Fruit Juices by Gas Chromatography-High Resolution Mass Spectrometry.

A new polyvalent wide-scope analytical method, valid for both raw and processed (juices) fruits, combining target and non-target strategies, has been developed and validated to determine low concentrations of 260 pesticides, as well as many potential non-target substances and metabolites. The target approach has been validated according to SANTE Guide requirements. Trueness, precision, linearity, and robustness values were validated in raw fruit (apple) and juice (apple juice) as representative solid and liquid food commodities. Recoveries were between 70-120% and two ranges of linearity were observed: 0.5-20 µg kg-1 (0.5-20 µg L-1 apple juice) and 20-100 µg kg-1 (20-100 µg L-1 apple juice). The limits of quantification (LOQs) reached were lower than 0.2 µg kg-1 in apple (0.2 µg L-1 apple juice) in most cases. The developed method, based on QuEChERS extraction followed by gas chromatography-high resolution mass spectrometry (GC-HRMS), achieves part-per-trillions lower limits, which allowed the detection of 18 pesticides in commercial samples. The non-target approach is based on a retrospective analysis of suspect compounds, which has been optimized to detect up to 25 additional compounds, increasing the scope of the method. This made it possible to confirm the presence of two pesticide metabolites which were not considered in the target screening, phtamlimide and tetrahydrophthalimide.

Assessment of wastewater pollution by gas chromatography and high resolution Orbitrap mass spectrometry.

As a novelty, the combination of headspace solid phase microextraction and gas chromatography coupled to an Orbitrap mass analyzer in full scan mode (HS-SPME-GC-Orbitrap-MS) was evaluated for the monitoring of organic pollutants in wastewaters. The developed methodology showed good linearity (R2 > 0.999), sensitivity as well as suitable relative recoveries (89-115%) and precision values (RSD = 1-16%) for 15 polycyclic aromatic hydrocarbons (PAHs) selected as target compounds. Naphthalene, acenapthene and phenanthrene were found in the analyzed samples (influent and effluent wastewaters). Naphthalene was present in 62% of them, ranging from 1.33 to 24.32 ng L-1. Acenapthene was observed in 1 single sample (4.17 ng L-1) while phenanthrene was found in 7 samples (1.51-8.67 ng L-1). In addition, in order to identify other pollutants in the samples, retrospective analyses were addressed through target and non-target screenings. An in-house database containing close to 1,000 pollutants including, among others, polychlorinated biphenyls (PCBs), brominated diphenyl ethers (BDEs) and pesticides, was applied in the post-target analysis. For the non-target screening, after a deconvolution process, high resolution filtering (HRF) and Kovats retention index (KI) were used for tentative analyte identification. Thus, 51 additional pollutants were tentatively identified in the wastewaters, most of them used as flavoring agents and household product ingredients, highlighting the presence of linear alkyl benzenes (LABs).

1H NMR and multi-technique data fusion as metabolomic tool for the classification of golden rums by multivariate statistical analysis.

1H NMR spectroscopy combined with chemometrics was applied for the first time for golden rum classification based on several factors as fermentation barrel, raw material, distillation method and aging. Principal component analysis (PCA) was used to assess the overall structure, and partial least square discriminant analysis (PLS-DA) was carried out for the analytical discrimination of rums. Additionally, data-fusion of 1H NMR and chromatographic techniques (gas and liquid chromatography) coupled to mass spectrometry was applied to provide more accurate knowledge about rums. This approach provided a classification of samples with lower error rate than the one obtained by the use of a single technique (spectroscopic or chromatographic). The results showed that 1H NMR spectroscopy is an appropriate technique for the suitable classification of >95.5% of the samples. When data fusion methodology of spectroscopic and spectrometric data was performed, the prediction efficiency can reach 100% of the samples.

An Innovative Metabolomic Approach for Golden Rum Classification Combining Ultrahigh-Performance Liquid Chromatography-Orbitrap Mass Spectrometry and Chemometric Strategies.

A comprehensive fingerprinting strategy for golden rum classification considering different categories such as fermentation barrel, raw material, and aging is provided, using a metabolomic fingerprinting approach. A nontarget fingerprinting of 30 different rums using liquid chromatography coupled to high-resolution mass spectrometry (Exactive Orbitrap mass analyzer, LC-HRMS) was applied. Principal component analysis (PCA) was used to assess the overall structure of the data and to identify potential outliers. Different chemometric analyses such as partial least-squares discriminant analysis (PLS-DA) were used. A variable importance in projection (VIP) selection method was applied to identify the most significant markers that allow group separation. Compounds related to aging and fermentation processes such as furfural derivates (e.g., hydroxymethylfurfural) and sugars (e.g., glucose, mannitol) were found as the most discriminant compounds (VIP threshold value >1.5). Suitable separation according to selected categories was achieved, and a classification ability of the models of close to 100% was achieved.

Automated Determination of Xenobiotics (Pesticides, PCBs, PAHs, and PBDEs) in Sediment Samples Applying HS-SPME-GC-HRMS.

Background: Automated methods are needed for the reliable determination of xenobiotics in environmental samples. Objective: Optimization and application of an automated method for the ultra-trace analysis of 34 organic contaminants including polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), organochlorinated (OCPs), and organophosphorus pesticides (OPPs) in sediment samples have been performed. Methods: Automated method based on headspace solid-phase microextraction (SPME) coupled to GC-high-resolution MS (GC-HRMS) for the ultra-trace analysis of the targeted compounds has been developed. Conclusions: Suitable validation parameters in terms of linearity, trueness, selectivity, intraday and interday precision, LODs, and LOQs were obtained. Relative recovery values between 70 and 120% were achieved for all compounds (concentration levels assayed 1 and 10 µg/kg). RSD values were always lower than 25% for intra- and interday precision, and LODs and LOQs were 0.1 and 1.0 µg/kg, respectively, for all analytes. Highlights: The proposed method was applied to the analysis of sediments collected in Andalusia, Spain, and Poland, finding PCB 18 in one sample (15.9 µg/kg) and p,p'-DDE in several samples at concentrations ranging from 27.6 to 297.2 µg/kg.

Pushing the frontiers: boron-11 NMR as a method for quantitative boron analysis and its application to determine boric acid in commercial biocides.

Quantitative boron-11 NMR (11B qNMR) spectroscopy has been introduced for the first time as a method to determine boric acid content in commercial biocides. Validation of the method affords a limit of detection of 0.02% w/w and a limit of quantification of 0.04% w/w, which are low enough to determine boric acid in commercial biocides. Other figures of merit such as linearity (R2 > 0.99), recovery (93.6%-106.2%), intra- and inter-day precision (from 0.7 to 2.0%), uncertainty (3.7 to 4.4%) and matrix effects were also evaluated. This method was successfully applied to determine boric acid in five different commercial biocides in a wide range of concentrations (<0.05 to 10% w/w) providing excellent results when they were compared with those obtained using inductively coupled plasma-mass spectrometry (ICP-MS). The suitability of this method for a fast and reliable quantification of boric acid in commercial biocide preparations has been demonstrated. The absence of the matrix effect allows the application of this validated method for the determination of boric acid in other matrices of diverse composition.

Automated and simultaneous determination of priority substances and polychlorinated biphenyls in wastewater using headspace solid phase microextraction and high resolution mass spectrometry.

The re-use of wastewater has been in growing demand but a possible negative feature is the possibility of organic pollutants being present after its treatment. In order to control the presence of contaminants in wastewater, a completely automated methodology capable of determining a total of 55 organic pollutants including pesticides, polycyclic aromatic hydrocarbons (PAHs), brominated diphenyl ethers (BDEs) and polychlorinated biphenyls (PCBs) at ultra-trace levels has been developed. The proposed method is based on an on-line combination of headspace solid phase microextraction (HS-SPME) and gas chromatography coupled to double-focusing magnetic sector high resolution mass spectrometry (GC-HRMS). HS-SPME as well as GC-HRMS conditions were optimized so as to achieve maximum extraction efficiency and sensitivity which was reinforced by using multiple ion detection (MID) as acquisition mode. Special attention was directed to fiber conditioning and stability by calorimetric and scanning electron microscopy (SEM) analysis. Method validation showed good linearity (R2 > 0.99), recoveries between 86 and 113%, relative standard deviation (RSD) values < 20% for intra-day and inter-day precision and quantification limits (LOQs) between 0.01 and 350 ng L-1. Finally, the proposed method was successfully applied to wastewater samples revealing the presence of PAHs and PCBsS and certain pesticides, mainly anthracene, chlorpyrifos, p,p'-DDD and p,p'-DDT and the metabolite p,p'-DDE.

Development and Validation of a Multiresidue Method for the Determination of Pesticides in Dry Samples (Rice and Wheat Flour) Using Liquid Chromatography/Triple Quadrupole Tandem Mass Spectrometry.

A rapid and sensitive multiresidue method was developed and validated for the determination of around 100 pesticides in dry samples (rice and wheat flour) by ultra-performance LC coupled to a triple quadrupole mass analyzer working in tandem mode (UPLC/QqQ-MS/MS). The sample preparation step was optimized for both matrixes. Pesticides were extracted from rice samples using aqueous ethyl acetate, while aqueous acetonitrile extraction [modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method] was used for wheat flour matrixes. In both cases the extracts were then cleaned up by dispersive solid phase extraction with MgSO4 and primary secondary amine+C18 sorbents. A further cleanup step with Florisil was necessary to remove fat in wheat flour. The method was validated at two concentration levels (3.6 and 40 µg/kg for most compounds), obtaining recoveries ranging from 70 to 120%, intraday and interday precision values≤20% expressed as RSDs, and expanded uncertainty values≤50%. The LOQ values ranged between 3.6 and 20 µg/kg, although it was set at 3.6 µg/kg for the majority of the pesticides. The method was applied to the analysis of 20 real samples, and no pesticides were detected.

Occurrence of pesticide residues and transformation products in different types of dietary supplements.

The purpose of this study was to evaluate the presence of pesticide residues and transformation products in dietary supplement products. Thirty-two samples were analysed to determine 177 pesticides by gas chromatography-tandem mass spectrometry (GC-MS/MS) and 333 pesticides by liquid chromatography-high-resolution mass spectrometry (LC-HRMS). Pesticides were extracted from different kinds of dietary supplements by the use of a modified QuEChERS extraction method. Six samples contained pesticide residues at concentration up to 92.7 µg kg(-1), but only butralin exceeded the maximum residue limits set for raw material. In addition to target compounds, LC-HRMS enables the simultaneous detection of non-target pesticides. In this case, transformation products of pesticides were detected in the analysed samples using HRMS analyser (Exactive-Orbitrap). These compounds were not included in the original method, and they were monitored as post-target compounds, knowing their molecular formula and exact mass. Mass accuracy was always < 2 ppm, corresponding to a maximum mass error. The positive findings endorse the idea that a deeper and continuous investigation of pesticide residues and transformation products in dietary supplement products is necessary in order to guaranty consumer's safety.

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.

On-line purge and trap GC-MS for monitoring 1,3-dichloropropene in agricultural water and soil samples.

A simple and reliable method using on-line purge and trap gas chromatography mass spectrometry has been developed for the determination of the fumigant 1,3-dichloropropene (1,3-DCP) in agricultural water and soil samples. The proposed analytical methodology was validated in the target environmental matrices by the analysis of spiked blank matrix samples. Limit of detection values of 0.05 microg/L for water and 0.005 microg/Kg for soils were obtained, while limits of quantitation were of 0.1 microg/L for water and 0.01 mg/kg for soils. Good recoveries (93-104%) and precision values (< 6%) were obtained for the target compound in the studied matrices. This methodology has been successfully applied to the analysis of incurred groundwater samples from an agricultural area, The Campo de Dalías (Almería, South Spain), although 1,3-DCP was not detected. The method was also applied to soil samples from greenhouse treated with a soil fumigant containing 1,3-DCP.