Determination of glyphosate in cadaveric insect samples using UHPLC-MS/MS method

Many countries reported cases of acute intoxication with glyphosate or glyphosate herbicides. The aim of this work was to determine glyphosate from necrophagous insects. Calliphora vicina Robineau-Desvoidy and Dermestes maculatus DeGeer are widely distributed species of medical and forensic interest. These insects were fed with a pork homogenate and 7.69 ml/kg Roundup Full® II (potassium salt of n-phosphonomethyl glycine 66.2 % p/v), and were kept in an incubator at 30 ± 0.1 °C, 42 ± 3 % relative humidity, and 12:12 h light/dark. In hide beetles, two trials were conducted: for the first, two groups of larvae were selected, L1-L4 and L5-L7, because this latter group had larval instars that can molt to pupa. The second trial was performed to determine if glyphosate was found in L1 and L3 due to the results obtained in the first trial. In Diptera, oldest feeding L3 and pupae were selected. All specimens were kept at -20 °C until toxicological analysis, which was carried out by UHPLC-MS/MS. In dermestids, glyphosate was determined only in the L1-L4 group (0.15 ppb) and in L1 (0.21 ppb) and L3 (0.20 ppb). In Diptera, glyphosate was determined only in L3 (0.25 ppb). Lastly, these preliminary results would suggest that herbicide-positive larval stages could be used for toxicological analysis in court cases.