Determination of Profenofos Residues using LC-MS/MS and Its Dissipation Kinetics in Pigeonpea Pods

Abstract

Background: Pigeonpea is a drought resistant legume crop, cultivated in semiarid tropical and subtropical regions of the world mainly for its protein enriched seeds. Insect pests are major biotic constraints implicating yield losses of staggering dimensions. Profenofos is being used for management of pigeonpea pod borer and studying the pattern of dissipation, residual occurrence and hazard index for consumption of pigeonpea grain contaminated with profenofos is very important. Methods: A simple, sensitive and reproducible method for analysis of profenofos in pigeonpea green pods and dry grain was standardized and validated using liquid chromatography tandem mass spectrometry (LC-MS/MS) with electro spray ionization (ESI+). Modified QuEChERS methods with 1 % ethyl acetate in acetonitrile involved in the extraction of profenofos residues from green pods and mature dry grains. Results: The limit of detection and limit of quantification (LOD and LOQ) were 0.002 and 0.006 µgg-1, respectively. The recovery ranges from 88.75 to 101.36 % for the green pods and 88.34 to 98.77 % for mature dry grains with relative standard deviation (RSD) was in the range of 0.99 to 4.05 %. The field study was conducted to investigate the dissipation kinetics of profenofos in pigeonpea. Two applications of profenofos 50 % EC at 500 and 1000 g a.i.ha-1 at 15 days intervals in pigeonpea at the time of pod formation recorded initial deposits of 20.28 and 41.64 ìgg-1 in the green pod, respectively. At15 days after application, residues gradually dissipated to the level of 0.78 and 1.98 µg g-1 accounting to the loss of 96.15 and 95.58 % at 500 and 1000 g a.i. ha-1, respectively. The half-life values were 5.18 and 5.93 days. Hazard index (HI) was found less than 1 at 25th and 35th day after application at 500 and 1000 g a. i. ha-1, respectively.

Determination of 77 Multiclass Pesticides and Their Metabolitesin Capsicum and Tomato Using GC-MS/MS and LC-MS/MS

“…The uncertainty values associated with the method for Capsicum and tomato matrices was found acceptable. Similar results observed with estimation uncertainty during analysis of spent leaves, made tea and tea infusion was found acceptable for most of the pesticides and it indicated that the method has high sensitivity and is suitable for multi-residues analysis [ 41 , 43 ] and results are in accordance with estimation of uncertainty in a pigeonpea matrix analyzed with GC-MS/MS and LC-MS/MS [ 33 ].…”

“…The present method was in accordance with the methods developed for determination of pesticides residues in pepper was found acceptable interms its accuracy, repeatability and reproducibility [ 13 , 26 , 27 , 28 ]; analysis of tricyclazole in rice with lowest detection level (0.002 μg g –1 ) was achieved and could be useful for monitoring of rice samples subjected to export [ 29 ]; chlorantraniliprole, indoxacarb and profenofos analysis in pigeonpea following a method standardized through LC-MS/MS with lowest detection and quantification level [ 30 , 31 , 32 ] and multiple residues in pigeonpea [ 33 ]. Pyridaben analysis in unprocessed and processed peppers [ 13 ] and etoxazole [ 34 ] are promising methods to identify and quantify the corresponding residues.…”

“…The statistical methods mentioned in the EURACHEM/CITAC Guide was followed to estimate the measurement of uncertainty in food samples [ 43 , 45 ]. The procedure explained for estimation of measurement uncertainty in pigeonpea matrix was followed for calculation of measurement uncertainty for intra laboratory validation (for recovery) of multiresidue residue analytical method for Capsicum and tomato [ 33 ].…”

“…The quick, easy, cheap, effective, rugged and safe (QuEChERS) method of sample extraction has been widely adopted for the multiresidue analysis of different matrices [ 23 , 24 , 25 ]. Application of modified QuEChERS methods in peppers to determine pesticideresidues was reported [ 13 , 26 , 27 , 28 ], including analysis of tricyclazole in rice [ 29 ] chlorantraniliprole in pigeonpea [ 30 ]; indoxacarb in pigeonpea [ 31 ]; profenofos in pigeonpea [ 32 ]; multiple residues in pigeonpea [ 33 ]. The detection of pyridaben in unprocessed and processed peppers [ 15 ]; etoxazole [ 34 ] and a group of 16 pesticides [ 35 ] in hot peppers using LC-MS/MS are a few reports of suitable methods.…”

Assessment and Characterization of Residual Concentrations from Some Cook-in Food Packages Utilized in Nigeria – ‘Moi-Moi’: A Case Study

“…Six ( 6) VOCs (isoprene, toluene, cumene, polyvinyl alcohol, carbontetrachloride, chloroform) were detected in the raw 'moi-moi' paste and upon cooking, all showed a decrease in concentration at day O. However, polyvinyl alcohol, carbontetrachloride, chloroform and toluene showed increase in their concentrations on day 3 while benzene and myrcene which were not originally in the raw 'moi-moi' paste were detected in the cooked 'moi-moi' on day 3 This further underlines the reports that migrations from food packages into the packaged food increases with increase in contact time [1,33,34]. Isoprene has been listed on the US Hazardous Substance fact sheet [35] as one of the volatile organic compound posing a health risk to humans upon exposure and since it is carcinogenic, there is no maximum limit of exposure.…”