Matrix-matched standards in the liquid chromatography-mass spectrometry determination of neonicotinoids in soil and sediment

The use of matrix-matched standards with a solid-liquid extraction and salting out without the addition of further cleanup steps or costly cleanup procedures associated with the quick, easy, cheap, effective, robust, and safe (QuEChERS) method was evaluated to address variations in ionization efficiency in the LC-MS/MS determination of neonicotinoid pesticides in complex environmental samples. Limits of detection (1.4-3.4 ng/g) and limits of quantitation (4.6-11.3 ng/g) for various neonicotinoid analogs were comparable to previously reported QuEChERS extraction methods. Mean recovery of standard neonicotinoid samples spiked with 10 ng/g was found to be 78.0-100.5%, while samples spiked with 100 ng/g were found to be 55.1-99.9%. Recovery of analytes was matrix dependent; the highest recovery was from sediment (86.2-100.5%) followed by laboratory sand (70.9-81.7%) and agricultural soil (55.5-102.6%), respectively. Optimization of this methodology resulted in the reduction of procedure time and cost, and can aid in environmental monitoring efforts of common neonicotinoid pesticides in soils and sediments.