Asma Rahman, Mian. A. Ali and Eny. M. Vieira
This study describes the refined analytical method for extraction and determination of thiamethoxam and imidacloprid pesticide residues in stingless bee (Meliponascutellaris). QuEChERS approach was used to develop a method for extraction, samples were extracted with acetonitrile (ACN), followed by salting out, solid phase extraction (SPE), cleanup with mixture of PSA and C18 sorbents while detection was performed by using high performance liquid chromatography coupled with diode-array detector (HPLC-DAD) and LC-MS/MS. The techniques were proven satisfactory by exhibited the linear chromatographic response ranges from 0.1 to 1μg mL-1 for the tested pesticides, with correlation coefficients above 0.998. The Limit of detection (LOD) and Limit of Quantification (LOQ) for thiamethoxam were 1.01 and 3.06 μg mL-1 by HPLCDAD while 0.1 and 0.3 μg mL-1 by LC-MS/MS and for imidacloprid were 1.04 and 3.15 g mL-1 by HPLC-DAD while 0.04 and 0.1 μg mL-1 by LC-MS/MS respectively. The proposed methods did not require more than 10 minutes for analysis; both the pesticides thiamethoxam and imidacloprid were observed in a very short retention time of 3.1 and 4.2 minutes. Good recoveries were observed for analytes, ranged between 70% and 120% with relative standard deviations between replicates of <10%. This method provides lower detection limits and improved recovery of thiamethoxam and imidacloprid, which will help researchers to evaluate their potential negative impact on environment and ecology.
