Optimization and Validation of LLE/HPLC-DAD Method to Determine the Residues of Selected PAHs in Surface Water

Abstract A rapid precise and accurate method was optimized and validated for the simultaneous determination of 6 PAHs (naphthalene, acenaphthalene, phenanthrene, fluoranthrene, anthracene and pyrene) in water by HPLC and their distribution in surface water (water from Yamuna river in Wazirabad and Okhla region and Aakulam lake, Kerala) were undertaken. The High-Pressure Liquid Chromatography (HPLC) separation of 6 PAHs was carried out by C-18 column with gradient elution of acetonitrile and water with diode-array detection (DAD). The method was optimized by using liquid-liquid extraction (LLE) with different solvent like hexane, dichloromethane and ethyl acetate and extract cleaned by adsorption column cleanup using different adsorbent like silica gel, alumina and florisil. Among the three solvents used for LLE, dichloromethane gave maximum extraction efficiency (70.27-91.09%). For the cleanup of water extract, a florisil column using 20:80 acetone:hexane as the eluting solvent gave recovery of 91.2-97.2 µg and 8.9-9.6 µg at 100 µg and 10 µg of PAHs loaded in the column, respectively. The total method recovery using dichloromethane as the extracting solvent and 20:80 acetone: hexane as the eluting solvent for florisil column clean up varied from 71.02-89.74%. Limit of detection (LOD), limit of quantiûcation (LOQ), and correlation coefficients were found in the range of 0.1 to 1.5 ìg L Highlights A rapid, precise and accurate method was optimized and validated for simultaneous determination of 6 PAHs in water by HPLC with a method recovery of 71.02-89.74

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Quantitative Screening of Agrochemical Residues in Fruits and Vegetables by Buffered Ethyl Acetate Extraction and LC-MS/MS Analysis

A buffered ethyl acetate extraction method is proposed for the simultaneous analysis of 296 agrochemicals in a wide range of fruit and vegetable matrices by liquid chromatography–tandem mass spectrometry (LC-MS/MS). The optimized quantity of acetate buffer (1% acetic acid + 0.5 g of sodium acetate per 10 g of sample) adjusted the pH of each test matrix to 5–6, which in turn significantly improved recoveries of acidic and basic compounds. The role of diethylene glycol (used in the evaporation step) on signal suppression of certain compounds was evaluated, and its quantity was optimized to minimize such an effect. The method was validated in grape, mango, drumstick, bitter gourd, capsicum, curry leaf, and okra as per the DG-SANCO/12571/2013 guidelines. Recoveries in the fortification range of 1–40 μg/kg were within 70–120% with associated relative standard deviations below 20% for most of the compounds. The method has potential for regulatory and commercial applications with a generic approach

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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

Quantitative Screening of Agrochemical Residues in Fruits and Vegetables by Buffered Ethyl Acetate Extraction and LC-MS/MS Analysis

A buffered ethyl acetate extraction method is proposed for the simultaneous analysis of 296 agrochemicals in a wide range of fruit and vegetable matrices by liquid chromatography–tandem mass spectrometry (LC-MS/MS). The optimized quantity of acetate buffer (1% acetic acid + 0.5 g of sodium acetate per 10 g of sample) adjusted the pH of each test matrix to 5–6, which in turn significantly improved recoveries of acidic and basic compounds. The role of diethylene glycol (used in the evaporation step) on signal suppression of certain compounds was evaluated, and its quantity was optimized to minimize such an effect. The method was validated in grape, mango, drumstick, bitter gourd, capsicum, curry leaf, and okra as per the DG-SANCO/12571/2013 guidelines. Recoveries in the fortification range of 1–40 μg/kg were within 70–120% with associated relative standard deviations below 20% for most of the compounds. The method has potential for regulatory and commercial applications with a generic approach

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Not AvailableIn an ongoing field experiment, organic and conventional farming (control) were compared for onion bulb yield, biochemical quality, soil organic carbon (SOC), and microbial activity after the sixth cropping cycle. The treatments used for organic production were farmyard manure (FYM, 20,000 kg ha−1), poultry manure (PM, 10,000 kg ha−1), vermicompost (VC, 10,000 kg ha−1), neem cake (NC, 5000 kg ha−1), and a combination of FYM (5000 kg ha−1), PM (2500 kg ha−1), VC (2500 kg ha−1), and NC (1250 kg ha−1); all treatments were compared with the control. Organic treatments produced 24.6–43.6% lower yield consistently for 6 years than the control treatment. No significant difference was observed between PM, FYM, and VC treatments for the bulb yield. Bulb analysis during the sixth year indicated that plants that received FYM, PM, or VC had higher levels of total phenol, total flavonoid, ascorbic acid, and quercetin-3-glucoside than the control plants. All the five organically treated sets had significantly higher values of SOC, microbial population, fungal-to-bacterial ratio, and dehydrogenase activity than the control and the initial values in each treated set. The results indicate that FYM, PM, or VC application enhances biochemical quality and organic farming is more sustainable than conventional farming.Not Availabl

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Not AvailableA residue analysis method was validated for trace level estimation of pyraclostrobin by liquid chromatography– mass spectrometry and metiram (analyzed as CS2) by gas chromatography mass spectrometry in grapes and raisin matrix. Dissipation of their residues and processing factors (PFs) during raisin making were evaluated through field studies with applications at single dose (SD) and double dose (DD). Residue data during drying process were best fitted to first+first order kinetics model giving half-life ranging between 6 and 7 days for pyroclostrobin and 4 days for metiram. PFs for metiram and pyraclostrobin related to washing and oil dipping were 0.47 and 0.41, and 0.78 and 0.63 at single dose (SD) and double dose (DD), respectively. PF value of >1 for drying (1.01 and 1.31 for metiram and 1.34 and 1.10 for pyraclostrobin) indicates concentration of the residues during the drying process. The dietary exposure corresponding to average daily consumption of 0.0043 kg raisin per day on each sampling day was less than the respective maximum permissible intake at both the doses.Not Availabl

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Not AvailableIn an ongoing field experiment, organic and conventional farming (control) were compared for onion bulb yield, biochemical quality, soil organic carbon (SOC), and microbial activity after the sixth cropping cycle. The treatments used for organic production were farmyard manure (FYM, 20,000 kg ha−1), poultry manure (PM, 10,000 kg ha−1), vermicompost (VC, 10,000 kg ha−1), neem cake (NC, 5000 kg ha−1), and a combination of FYM (5000 kg ha−1), PM (2500 kg ha−1), VC (2500 kg ha−1), and NC (1250 kg ha−1); all treatments were compared with the control. Organic treatments produced 24.6–43.6% lower yield consistently for 6 years than the control treatment. No significant difference was observed between PM, FYM, and VC treatments for the bulb yield. Bulb analysis during the sixth year indicated that plants that received FYM, PM, or VC had higher levels of total phenol, total flavonoid, ascorbic acid, and quercetin-3-glucoside than the control plants. All the five organically treated sets had significantly higher values of SOC, microbial population, fungal-to-bacterial ratio, and dehydrogenase activity than the control and the initial values in each treated set. The results indicate that FYM, PM, or VC application enhances biochemical quality and organic farming is more sustainable than conventional farming.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

Comparison of organic and conventional farming for onion yield, biochemical quality, soil organic carbon, and microbial population

<p>In an ongoing field experiment, organic and conventional farming (control) were compared for onion bulb yield, biochemical quality, soil organic carbon (SOC), and microbial activity after the sixth cropping cycle. The treatments used for organic production were farmyard manure (FYM, 20,000 kg ha⁻¹), poultry manure (PM, 10,000 kg ha⁻¹), vermicompost (VC, 10,000 kg ha⁻¹), neem cake (NC, 5000 kg ha⁻¹), and a combination of FYM (5000 kg ha⁻¹), PM (2500 kg ha⁻¹), VC (2500 kg ha⁻¹), and NC (1250 kg ha⁻¹); all treatments were compared with the control. Organic treatments produced 24.6–43.6% lower yield consistently for 6 years than the control treatment. No significant difference was observed between PM, FYM, and VC treatments for the bulb yield. Bulb analysis during the sixth year indicated that plants that received FYM, PM, or VC had higher levels of total phenol, total flavonoid, ascorbic acid, and quercetin-3-glucoside than the control plants. All the five organically treated sets had significantly higher values of SOC, microbial population, fungal-to-bacterial ratio, and dehydrogenase activity than the control and the initial values in each treated set. The results indicate that FYM, PM, or VC application enhances biochemical quality and organic farming is more sustainable than conventional farming.</p