Improved chromatographic performance in red chilli powder pesticide residue quantitation by retention gap introduction in gas chromatography tandem mass spectrometry.

Analysis of agrochemical residues in red chilli powder is always considered difficult because of higher matrix interference due to carotenoid pigments and other co-extractives. During the sample preparation, matrix components were co-extracted along with the target compounds leading to frequent source cleaning, changing of liner and column. Efforts were made to improve the chromatographic performance by optimizing sample preparation, choosing matrix-free transitions and introducing a retention gap. The Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) extraction was experimented using different dispersive adsorbents and the purified extract was analyzed by gas chromatography tandem mass spectrometry (GC-MS/MS) system. 84 pesticides under different class were validated and established a limit of quantification of 0.002-0.007 mgkg-1. The recovery was between 70 and 110% at 0.01, 0.025 and 0.05 mgkg-1 fortification level and corresponding precision was between 3 and 16% RSD. Suitability of the validated method was established through analysis of market samples of chilli powder for the quantitation of targeted pesticide residues. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-021-05177-3.

Multiresidue analysis of pesticides, polyaromatic hydrocarbons and polychlorinated biphenyls in poultry meat and chicken eggs by GC-MS/MS: method development and validation.

The study uses gas chromatography with tandem mass spectrometry (GC-MS/MS) to develop a reliable analytical approach for detecting multiclass pesticides, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in poultry meat and chicken eggs. The meat (2 g) and egg (4 g) samples were extracted with acidified acetonitrile (10 mL) as part of the optimized sample preparation technique. The cleanup consisted of freezing an aliquot of the extract (5 mL) at -20 °C, followed by dispersive solid phase extraction using 50 mg PSA + 100 mg C18+150 mg MgSO4. The matrix co-extractives were effectively removed and the method performance met the European Commission's analytical quality control criteria (SANTE/12682/2019). The method was validated at two spiking levels (10 and 20 ng/g of 225 pesticides, 9 PAHs and 8 PCBs), and good recoveries (70-120%) and precision-RSDs (≤20%) were achieved for 90% of the targeted pesticide residues. For 80% of the compounds, the LOQs were ≤10 ng/g. The results of the intra-laboratory (involving six analysts) and inter-laboratory validation studies (involving eight ISO 17025 accredited laboratories) established satisfactory ruggedness and reproducibility. It created potential applications in commercial residue testing laboratories for regulatory compliance check purposes.

Comparative evaluation of multi-residue methods for analysis of pesticide residues in black pepper by gas chromatography tandem mass spectrometry: critical evaluation of matrix co-extractives and method validation.

A gas chromatography tandem mass spectrometry method was developed for simultaneous determination of 133 pesticides in Black pepper (Piper nigrum). QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) sample preparation method is preferred over multistep methods. Extraction was done by using acetonitrile followed by clean up using graphitized carbon, primary secondary amine and octadecyl silica (C18). Even after the cleanup, non-volatile co-extractives stick to the liner and column which results in affecting the performance of the instrument and volatile co-extractives impact the analysis by enhancing the analyte concentration. So we evaluated a dilution procedure to overcome the drawbacks. The limit of quantification of 0.01 mg kg-1 was achieved for fifty times diluted sample extract with S/N ≥ 10. The recovery was between 70 and 120% for 0.01, 0.025 and 0.05 mg kg-1 for fortified samples and corresponding precision was between 3 and 16% RSD. The seven-level calibration curve shows a regression co-efficient of 0.99.

Multi-residue Analysis of Pesticides in Turmeric (Powder and Rhizome) Using Gas Chromatography Tandem Mass Spectrometry.

BACKGROUND AND OBJECTIVES: Turmeric is widely used as an ingredient of food and medicinal products. There exists no validated method for multi-residue analysis of pesticides in turmeric. OBJECTIVE: This study was undertaken to develop a simple and robust method for the quantitative determination of multi-class pesticides in turmeric powder and rhizome by GC-MS/MS. METHOD: Initially, the samples were soaked in water for 30 min and homogenized to a fine paste. A portion of this paste (2 g) was extracted with acetonitrile (2 mL) and partitioned with hexane (2 mL) after adding 5 mL of 20% NaCl. The cleanup step involved dispersive solid phase extraction with graphitized carbon black (GCB, 5 mg/mL). Its performance was evaluated against primary secondary amine (PSA) and C18 sorbents. The cleaned extract was evaporated to dryness and reconstituted in ethyl acetate before GC-MS/MS analysis. The method was validated for a mixture of 208 multi-class pesticides at 10 ng/g and higher levels (i.e., 20 and 50 ng/g). RESULTS: The findings, which demonstrated a satisfactory recovery and precision (RSDs <20%) for all compounds at 10 ng/g and higher spiking levels, are aligned with the analytical quality control criteria of SANTE/12682/2019 guidelines. The cleanup effect of GCB was much superior to that of PSA, C18, and their combinations. The solvent exchange step with hexane was effective in removing co-extractives and minimizing matrix effects. CONCLUSIONS: This method complies with the regulatory requirements and is fit-for-purpose for pesticide residue monitoring in turmeric. HIGHLIGHTS: The study reports a validated GC-MS/MS method for multi-residue analysis of pesticides in turmeric for the first time. The method provided a high throughput analysis of multi-class pesticides in turmeric rhizome and powder matrices with satisfactory selectivity, sensitivity, accuracy, and precision.

Pesticide residues in two frog species in a paddy agroecosystem in Palakkad district, Kerala, India.

Pesticides residues were quantified in 109 frogs comprising two species (Fejervarya limnocharis and Hoplobatrachus crassus) from organic and conventional paddy farms in Kerala, India. Seven frogs from conventional but none from the organic farms revealed deformities. Levels of total Organochlorines (OCs) (33.22 ng/g) and Synthetic Pyrethroid, Fenvalerate-II (26.91/42.15 ng/g) in deformed F. limnocharis and H. crassus were significantly greater than in healthy frogs. Among OCs in healthy frogs, traces of γ (gamma)-HCH (hexachlorocyclohexane) (2.12 ng/g) were found only in F. limnocharis from organic farm. Among Organophosphates, Phorate (1.02 ng/g) and Quinalphos (2.62 ng/g) were present in traces in deformed F. limnocharis, while Parathion ethyl (1.02 ng/g) was detected in deformed H. crassus. The data indicate that the high level of pesticides may have contributed to the deformity of frogs. Therefore, an elaborative study will be essential to conserve amphibians in India.

Multiresidue determination of 375 organic contaminants including pesticides, polychlorinated biphenyls and polyaromatic hydrocarbons in fruits and vegetables by gas chromatography-triple quadrupole mass spectrometry with introduction of semi-quantification approach.

A residue analysis method for the simultaneous estimation of 349 pesticides, 11 PCBs and 15 PAHs extracted from grape, pomegranate, okra, tomato and onion matrices, was established by using a gas chromatograph coupled to an electron impact ionization triple quadrupole mass spectrometer (GC-EI-MS/MS). The samples were extracted by ethyl acetate and cleaned by dispersive solid phase extraction with PSA and/or GCB/C(18) by the methods reported earlier. The GC-EI-MS/MS parameters were optimized for analysis of all the 375 compounds within a 40 min run time with limit of quantification for most of the compounds at <10 µg/L, which is well below their respective European Union-Maximum Residue Levels. The coefficient of determination (r(2)) was >0.99 within the calibration linearity range of <5-250 ng/mL for compounds with LOQs<5 ng/mL. While for the compounds with LOQs within 5-10 µg/kg, the lowest calibration level was 5 and 10 µg/kg as applicable. The recoveries at 10, 25 and 50 ng/mL were within 70-110% (n=6) with associated RSDs<20% indicating satisfactory precision. The information generated from the single laboratory validation was further utilized for building a semi-quantitative approach. The accuracies in quantification obtained via individual calibration standards vis-à-vis semi-quantification approach were comparable. For incurred samples, the concentrations estimated by the semi-quantification approach were within ±10% of the values obtained by direct quantification. This approach complements the existing GC-EI-MS/MS methods by offering targeted screening and quantification capabilities.