Neonicotinoids Detection by new LC-MS/MS Method in Romanian Surface Waters

Increasing and widespread use of neonicotinoid insecticides in all world, together with their highly toxicity to invertebrates and environmental persistence mean that surface waters need to be monitored for these compounds. In the 2015, neonicotinoid insecticides have been incorporated in the watch list of substances for a European Union monitoring program (495/2015/ EU). A new method using automated solid phase extraction (SPE) with polymeric cartridges (OASIS HLB) followed by LC-MS/MS provided good separation of the most common neonicotinoids compounds. The method was developed for the determination of four neonicotinoid insecticides (nitenpyram, thiamethoxam, clothianidin, acetamiprid) in surface water with low limit of quantification (0.3-0.9 ng/L, nano grams per liter). Recoveries in surface water samples fortified at 200 ng/L for each compound ranged from 71.4 to 109.9 %; relative standard deviation ranged from 4 to 9%. The method was applied to water samples from four streams in Romania, Danube River and its tributaries
(Arges River, Jiu River, and Olt River). The surface water samples were found to be contaminated clothianidin (1.08-6.4 ng/L) and by thiamethoxam (1.1-3.8ng/L). The highest concentrations were recorded in Danube River in Oltenita point (6.4ng/L) and in Gura-Vaii point (5.5ng/L). The concentration of acetamiprid and nitenpyram were situated below limit of quantification in all samples.