Sanjay Kumar Sahoo

Persistence of fipronil and its risk assessment on cabbage, Brassica oleracea var. capitata L.

Persistence of fipronil in cabbage was studied following three applications of Jump 80 WG at 75 and 150 g a.i. ha(-1) at 7 day interval. The average initial deposits of total fipronil (fipronil and its metabolites) were 1.226 and 2.704 mg kg(-1) on the heads following 3rd application of fipronil at single and double the dosages, respectively. Desulfinyl was found to be the main metabolite followed by sulfone and sulfide. Metabolite amide was not detected in cabbage samples. Half-life periods for fipronil were found to be 3.43 and 3.21 day at single and double the application rates, respectively. Risk assessment of fipronil to the consumers was calculated on the basis of per capita 80 g consumption of cabbage and comparing it to its ADI for an adult of 55 kg which was found to be less than its ADI on 10th day at both the dosages.

Estimation of β-cyfluthrin and imidacloprid in okra fruits and soil by chromatography techniques

Dissipation of β-cyfluthrin and imidacloprid in okra was studied following three applications of a combination formulation of Solomon 300 OD (β-cyfluthrin 9 % + imidacloprid 21 %) @ 60 and 120 g a.i. ha−1 at 7 days interval. Residues of β-cyfluthrin and imidacloprid in okra were estimated by gas liquid chromatography (GLC) and high performance liquid chromatography (HPLC), respectively. Residues of β-cyfluthrin were confirmed by gas chromatograph–mass spectrometry (GC-MS) and that of imidacloprid by high performance thin layer chromatography (HPTLC). Half-life periods for β-cyfluthrin were found to be 0.91 and 0.68 days whereas for imidacloprid these values were observed to be 0.85 and 0.96 days at single and double the application rates, respectively. Residues of β-cyfluthrin dissipated below its limit of quantification (LOQ) of 0.01 mg kg−1 after 3 and 5 days at single and double the application dosage, respectively. Similarly, residues of imidacloprid took 5 and 7 days to reach LOQ of 0.01 mg kg−1, at single and double dosages respectively. Soil samples collected after 15 days of the last application did not show the presence of β-cyfluthrin and imidacloprid at their detection limit of 0.01 mg kg−1.

Development and Validation of QuEChERS Method for Estimation of Chlorantraniliprole Residue in Vegetables

An easy, simple and efficient analytical method was standardized and validated for the estimation of residues of chlorantraniliprole in different vegetables comprising brinjal, cabbage, capsicum, cauliflower, okra, and tomato. QuEChERS method was used for the extraction and cleanup of chlorantraniliprole residues on these vegetables. Final clear extracts of ethyl acetate were concentrated under vacuum and reconstituted into high performance liquid chromatograph (HPLC) grade acetonitrile, and residues were estimated using HPLC equipped with PDA detector system, C(18) column and confirmed by liquid chromatograph mass spectrometer (LC-MS/MS), and high performance thin layer chromatograph (HPTLC). HPLC grade acetonitrile:water (80:20, v/v) was used as mobile phase @ 0.4 mL/min. Chlorantraniliprole presented distinct peak at retention time of 9.82 min. Consistent recoveries ranging from 85% to 96% for chlorantraniliprole were observed when samples were spiked at 0.10, 0.25, 0.50, and 1.00 mg/kg levels. The limit of quantification of this method was worked out to be 0.10 mg/kg.

Residual behaviour and risk assessment of flubendiamide on Chickpea (Cicer arietinum L.)

The study was undertaken to determine the disappearance trends of flubendiamide residues on chickpea under field conditions and thereby, ensure consumer safety. Average initial deposits of flubendiamide on chickpea pods were found to be 0.68 and 1.17 mg kg(-1), respectively, following three applications of flubendiamide 480SC @ 48 and 96 g a.i. ha(-1) at 7d intervals. Half-life of flubendiamide on chickpea pods was observed to be 1.39 and 1.44 d, respectively, at single and double dosages whereas with respect to chickpea leaves, these values were found to be 0.77 and 0.86 d. Desiodo flubendiamide was not detected at 0.05 mg kg(-1) level on chickpea samples collected at different intervals. Theoretical maximum residue contribution (TMRC) for flubendiamide was calculated and found to be well below the maximum permissible intake (MPI) on chickpea pods and leaves at 0-day (1 h after spraying) for the both dosages. Thus, the application of flubendiamide at the recommended dose on chickpea presents no human health risks and is safe to the consumers.

Risk assessment of β-cyfluthrin and imidacloprid in chickpea pods and leaves.

Dissipation of β-cyfluthrin and imidacloprid in chickpea pods and leaves was measured following three applications of Solomon 300 OD (β-cyfluthrin 9 percent +imidacloprid 21 percent) at 200 and 400mLha(-1). Residues of β-cyfluthrin on chickpea pods and leaves were found to be below its limit of quantification (LOQ) of 0.01mgkg(-1) after 7 days at both the dosages. Similarly, imidacloprid residues were found to be below its LOQ of 0.01mgkg(-1) at 10 days. Half-life periods on chickpea pods and leaves for β-cyfluthrin were found to be 1.06 and 0.58 days, whereas for imidacloprid these values were observed to be 2.07 and 1.75 days at recommended dose. As the theoretical maximum residue contributions on chickpea pods and leaves are found to be less than the maximum permissible intake values even on 0 day, therefore consumer health risks are minimal at both the dosages on chickpea.

Degradation pattern and risk assessment of chlorantraniliprole on berseem (Trifolium alexandrinum L.) using high performance liquid chromatography

The persistence pattern of chlorantraniliprole on berseem leaves and its risk assessment for the safety of cattle were studied. QuEChERS method was used for the extraction and cleanup of samples and the residues of chlorantraniliprole were estimated using high performance liquid chromatography (HPLC) and confirmed by Liquid Chromatograph-Mass Spectrometer (LCMS-MS). The dissipation studies on berseem were carried out by application of chlorantraniliprole at five different dosages i.e. 11.6, 17.1, 23.1, 34.7 and 46.2 g a.i. ha(-1). Average initial deposits of chlorantraniliprole were found to be 0.47, 0.61, 0.78, 1.15 and 1.31 mg kg(-1), respectively. The residues reached below determination limit (BDL) of 0.01 mg kg(-1) in 5, 7, 7, 10 and 10 days for 11.6, 17.1, 23.1, 34.7 and 46.2 g a.i. ha(-1) dosages, respectively. Half-life (t1/2) of chlorantraniliprole on berseem was observed to be 0.93, 1.14, 1.06, 1.00 and 1.33 days, respectively, at 11.6, 17.1, 23.1, 34.7 and 46.2 g a.i. ha(-1). It was found that the theoretical maximum residue contributions (TMRC) values reached below maximum permissible intake (MPI) on 0 day in berseem samples treated with chlorantraniliprole. These studies, therefore suggest that the use of chlorantraniliprole formulation at different dosages does not seem to pose any hazards to the consumers and a waiting period of one day is suggested to reduce the risk before consumption of berseem leaves. These data could provide guidance for the proper and safe use of this pesticide on berseem in India.

QUALITATIVE AND QUANTITATIVE ANALYSIS OF CHLORANTRANILIPROLE AND FLUBENDIAMIDE IN SOLUBLE CONCENTRATE FORMULATIONS BY HIGH PERFORMANCE THIN LAYER CHROMATOGRAPHY

A method was developed for the qualitative analysis of active ingredients in soluble concentrate (SC) formulations of chlorantraniliprole (Coragen 18.5 SC) and flubendiamide (Fame 480 SC). Known concentrations of the reference grade standards and the soluble concentrate of chlorantraniliprole and flubendiamide dissolved in acetonitrile were applied on silica gel 60 F254 HPTLC plates using a Camag-Hamilton Linomat Syringe (100 μL). These plates were developed in horizontal chambers with ethyl acetate and methanol as mobile phase for chlorantraniliprole and flubendiamide, respectively. The amount of active ingredients present in formulations of chlorantraniliprole and flubendiamide were estimated by densitometry in a single beam, single wavelength reflectance mode at 270 and 252 nm, respectively. Calibration curves of these insecticides were linear in the range of 50–2000 ng and the correlation coefficients for the calibration equation were 0.998 and 0.996 for chlorantraniliprole and flubendiamide, respectively. The method has been validated by further analysis using high performance liquid chromatography (HPLC) with photo diode array (PDA) detector, and results were comparable. The method was found to be reproducible and convenient for quantitative analysis of these compounds. The proposed HPTLC method has its application for quality control and determination of the shelf life of commercial formulations of pesticides.

Persistence, dissipation and consumer risk assessment of a combination formulation of flubendiamide and deltamethrin on Cucumber

ABSTRACT Multi-location supervised field trials were conducted in India at four locations of the All India Network Project (AINP) on Pesticide Residues to study the persistence, dissipation and risk assessment of flubendiamide and deltamethrin on cucumber (Cucumis sativus). Residues of flubendiamide and deltamethrin on cucumber resulting from three spray applications of a combination formulation (flubendiamide 90% + deltamethrin 60%, 150 SC) at recommended (22.5 + 15 g a.i./ha) and double the recommended (45 + 30 g a.i./ha) dose were analysed. On the basis of persistence and dissipation studies, the half- life (T1/2) of flubendiamide on cucumber varied from 1.40 to 2.98 (recommended dose) and 1.55 to 2.76 days (double the recommended dose), while that of deltamethrin ranged from 2.5 to 4.9 (recommended dose) and 2.7 to 3.9 days (double the recommended dose) at the four locations. On the basis of supervised field trial data and using OECD calculator, MRLs in the combination product of 3 mg kg−1 for flubendiamide and 1.5 mg kg−1 for deltamethrin has been proposed for consideration by the Food Safety and Standards Authority of India (FSSAI). Codex, EU and EPA have fixed MRL of 0.2 mg kg−1 for flubendiamide and deltamethrin.

Persistence and Metabolism of Imidacloprid After Seed Treatment in Cotton Field Soil

A field study was carried out to determine the persistence and metabolism of imidacloprid in soil following its seed treatment @ 3.5 g and 14 g a.i. kg−1 of seed. Soil samples were collected at different time intervals from 7–90 days after application and the residues of imidacloprid and its metabolites (6-chloronicotinic acid, imidacloprid-nitrogunidine, olefin, nitrosimine, urea and 5-hydroxy) were quantified by high-performance liquid chromatography. The total imidacloprid residues in soil were mainly constituted by the parent compound followed by olefin and nitrosimine. The limit of quantification for the analysis of imidacloprid and its metabolites was worked out to be 0.01 mg kg−1. The maximum residues of total imidacloprid in soil samples collected 7 days after seed treatment were found to be 1.59 and 3.39 mg kg−1for the two dosages, rspectively. These residues could not be detected after 60 days for both the dosages. Nitrosamine metabolite was found to be the maximum followed by olefin. The half-life values (t 1/2) of total imidacloprid were calculated to be 23.89 and 26.65 days, respectively, when applied at recommended dose and four times the recommended dose, respectively.