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Not AvailablePublic exposure to pesticide residues through the main/side-stream smoke of tobacco (Nicotiana tabacum L.) is an international concern. This article reports optimization and validation of large-scale multiresidue analysis methods involving low pressure and traditional gas chromatography tandem mass spectrometry in compliance with the guidance residue levels (GRLs) of Cooperative Centre for Scientific Research Relative to Tobacco (CORESTA). Analysis by low pressure GC–MS/MS offered three times rapid turn around time over the traditional GC–MS/MS with limits of quantifications (LOQs) less than 2 g/L for all the 259 test compounds and the recoveries in the range of 70–118% (±20%) at 10 and 20 g/kg levels of fortification.Not Availabl

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Not AvailablePublic exposure to pesticide residues through the main/side-stream smoke of tobacco (Nicotiana tabacum L.) is an international concern. This article reports optimization and validation of large-scale multiresidue analysis methods involving low pressure and traditional gas chromatography tandem mass spectrometry in compliance with the guidance residue levels (GRLs) of Cooperative Centre for Scientific Research Relative to Tobacco (CORESTA). Analysis by low pressure GC–MS/MS offered three times rapid turn around time over the traditional GC–MS/MS with limits of quantifications (LOQs) less than 2 g/L for all the 259 test compounds and the recoveries in the range of 70–118% (±20%) at 10 and 20 g/kg levels of fortification.Not Availabl

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Not AvailableIn multiresidue analysis, as the complexity of matrix increases, matrix co-extractives might co-elute and interfere with the detection of target analytes, and thereby result in false positives and erroneous quantifications. This paper aims to evaluate the combination of enhanced mass resolution and concurrent selectivity and sensitivity in analyzing a complex mixture of 341 pesticides in grape, orange, tomato, okra and spinach by gas chromatography triple quadrupole mass spectrometry (GC–MS/MS). Timedselective reaction monitoring (t-SRM) was found advantageous over segment SRM in terms of ease of method optimization and sensitivity. The optimized t-SRM method was used to test the applicability of ultra-SRM (USRM) in filtering out co-eluting interfering matrix compounds. False detections of benfluralin, dimethoate, etc. could be avoided when mass resolution was increased from 0.7 to 0.4 and 0.2 Da (full width at half maximum). Similar observations were noted for chlorobenzilate, spiromesifen, tebuconazole, etc., in grape; omethoate, bendiocarb, monocrotophos, etc. in orange; omethoate, dimethoate, ethoxyquin, atrazine, etc., in tomato; and dichlobenil, omethoate, propoxur, monocrotophos, etc., in okra. The analysis at higher mass resolution could significantly minimize matrix effects (ME), e.g., 34% at 0.7 Da for spiroxamine in grape to 0.6% (0.4 Da) and −44% (0.7 Da) for dichlorvos in okra to 8.8% (0.1 Da). A feature called “quantitation enhanced data-dependent (QED) scan feature” was found effective in targeted screening to confirm the detection of atrazine, azoxystrobin, _-cyhalothrin, etc. at trace quantities in incurred samples and avoid false detection of chlorpyrifos.Not Availabl

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Not AvailableA single-step methanol extraction based method was developed and validated for simultaneous estimation of the residues of streptomycin and tetracycline group compounds in pomegranate fruits by LC−MS/MS. The limits of quantification for all target compounds were ≤0.005 mg kg−1 with recoveries (%) at fortification levels of 0.005, 0.01, and 0.05 mg kg−1 being within 90−116% (RSD ≤ 9%) and interday precision RSD ≤ 12% at 0.01 mg kg−1. A field experiment on the dissipation of streptomycin and tetracycline (including 4-epimers) residues in pomegranate fruits with regards to field applications of the commercial formulation Streptocycline SP (streptomycin sulfate 90% + tetracycline hydrochloride 10%) at 200 and 400 g a.i. ha−1 indicated preharvest intervals of 45 and 55 days for streptomycin and 12 and 15 days for tetracycline, respectively. The study will be useful in promoting effective residue monitoring and ensuring safe use of these antibiotics in managing bacterial diseases of pomegranate.Not Availabl

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Not AvailableA selective and sensitive multiresidue analysis method, comprising 4 7pesticides, was developed and validated in tobacco matrix. The optimized sample preparation procedure in combination with gas chromatography mass spectrometry in selected-ion-monitoring (GC-MS/SIM) mode offered limits of detection (LOD) and quantification (LOQ) in the range of 3–5 and 7.5–15 ng/g, respectively, with recoveries between 70 and 119% at 50–100 ng/g fortifications. In comparison to the modified QuEChERS (Quick-Easy- Cheap-Effective-Rugged-Safe method: 2 g tobacco + 10 ml water + 10 ml acetonitrile, 30 min vortexing, followed by dispersive solid phase extraction cleanup), the method performed better in minimizing matrix co-extractives e.g. nicotine and megastigmatrienone. Ambiguity in analysis due to co-elution of target analytes (e.g. transfluthrin-heptachlor) and with matrix co-extractives (e.g. -HCH-neophytadiene, 2,4-DDE-linolenic acid) could be resolved by selective multi-dimensional (MD)GC heart-cuts. The method holds promise in routine analysis owing to noticeable efficiency of 27 samples/person/day.Not Availabl

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Not AvailableA selective and sensitive multiresidue analysis method, comprising 4 7pesticides, was developed and validated in tobacco matrix. The optimized sample preparation procedure in combination with gas chromatography mass spectrometry in selected-ion-monitoring (GC-MS/SIM) mode offered limits of detection (LOD) and quantification (LOQ) in the range of 3–5 and 7.5–15 ng/g, respectively, with recoveries between 70 and 119% at 50–100 ng/g fortifications. In comparison to the modified QuEChERS (Quick-Easy- Cheap-Effective-Rugged-Safe method: 2 g tobacco + 10 ml water + 10 ml acetonitrile, 30 min vortexing, followed by dispersive solid phase extraction cleanup), the method performed better in minimizing matrix co-extractives e.g. nicotine and megastigmatrienone. Ambiguity in analysis due to co-elution of target analytes (e.g. transfluthrin-heptachlor) and with matrix co-extractives (e.g. -HCH-neophytadiene, 2,4-DDE-linolenic acid) could be resolved by selective multi-dimensional (MD)GC heart-cuts. The method holds promise in routine analysis owing to noticeable efficiency of 27 samples/person/day.Not Availabl

Validation of a Residue Analysis Method for Streptomycin and Tetracycline and Their Food Safety Evaluation in Pomegranate (<i>Punica granatum L.</i>)

A single-step methanol extraction based method was developed and validated for simultaneous estimation of the residues of streptomycin and tetracycline group compounds in pomegranate fruits by LC–MS/MS. The limits of quantification for all target compounds were ≤0.005 mg kg^–1 with recoveries (%) at fortification levels of 0.005, 0.01, and 0.05 mg kg^–1 being within 90–116% (RSD ≤ 9%) and interday precision RSD ≤ 12% at 0.01 mg kg^–1. A field experiment on the dissipation of streptomycin and tetracycline (including 4-epimers) residues in pomegranate fruits with regards to field applications of the commercial formulation Streptocycline SP (streptomycin sulfate 90% + tetracycline hydrochloride 10%) at 200 and 400 g a.i. ha^–1 indicated preharvest intervals of 45 and 55 days for streptomycin and 12 and 15 days for tetracycline, respectively. The study will be useful in promoting effective residue monitoring and ensuring safe use of these antibiotics in managing bacterial diseases of pomegranate

Validation of a GC–MS method for the estimation of dithiocarbamate fungicide residues and safety evaluation of mancozeb in fruits and vegetables

A sensitive and rugged residue analysis method was validated for the estimation of dithiocarbamate fungicides in a variety of fruit and vegetable matrices. The sample preparation method involved reaction of dithiocarbamates with Tin(II) chloride in aqueous HCl. The CS2 produced was absorbed into an isooctane layer and estimated by GC–MS selected ion monitoring. Limit of quantification (LOQ) was 640 lg kg1 for grape, green chilli, tomato, potato, brinjal, pineapple and chayote and the recoveries were within 75– 104% (RSD < 15% at LOQ). The method could be satisfactorily applied for analysis of real world samples. Dissipation of mancozeb, the most-used dithiocarbamate fungicide, in field followed first + first order kinetics with pre-harvest intervals of 2 and 4 days in brinjal, 7 and 10 days in grapes and 0 day in chilli at single and double dose of agricultural applications. Cooking practices were effective for removal of mancozeb residues from vegetables.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro en Investigación en Contaminación Ambiental (CICA