The Effects of Pretreatment with Dipping Solution on Variation of Bos-calid Residue in Grape Samples During Drying Process with Natural Sunlight

Abstract

Field experiments were carried out to investigate the variation of boscalid level during the drying period in grape samples that were pretreated and untreated with a dipping solution named POTAS prior to natural sunlight drying. Grape samples were collected at harvest and on the 3 rd , 7 th and 10 th days after harvest (during the drying process of the pretreated and untreated grapes). Initially, 360 different pesticides were scanned qualitatively by GC-MS and LC-MS/MS after QuEChERS (Quick, easy, cheap, effective, rugged and safe) extraction method and only boscalid was observed in grape samples. Consequently, study was concentrated on boscalid extraction and analysis. Boscalid residues were extracted and cleaned up using QuEChERS method. The analysis method shows a good linearity over the concentration range of 0.010-0.125 mg kg-1 with a correlation coefficient value of 0.998. Recoveries of the extraction and the analysis methods ranged from 74.8 to 100.8% within 0.7-1.7 % RSD at three different concentration levels. Detection and quantification limits were 0.77 and 2.55 µg kg-1 , respectively. The uncertainty of the method was calculated as 0.100±0.040 mg kg-1. The results showed that grapes pretreated with the dipping solution prior to drying process showed shorter drying times and higher boscalid degradation rate than those untreated.