Comparative study of neonicotinoid insecticides (NNIs) and NNI-Related substances (r-NNIs) in foodstuffs and indoor dust.

Comparative studies of neonicotinoid insecticides (NNIs) and NNI-related substances (r-NNIs) in foodstuffs and indoor dust are rare. Herein, we investigated the feature fragmentations of nine NNIs in high-energy collision dissociation cells via high-resolution orbitrap mass spectrometry and observed that NNIs can consistently generate several feature fragments (e.g., CHNCl, CHNSCl, and CHNF). Consequently, NNIs and r-NNIs were comprehensively (targeted, suspect, and feature fragment-dependent) detected in 107 foodstuff and 49 indoor dust samples collected from Nanjing City (eastern China). We fully or tentatively identified 9 target NNIs and 5 r-NNIs in these samples. NNIs and r-NNIs were detected in 93.5% of the analyzed foodstuff samples, and high concentrations were detected in vegetables (mean: 409 ng/g wet weight [ww]) and fruits (127 ng/g ww). Regarding indoor dust, imidacloprid and acetamiprid exhibited extremely high detection frequencies and contamination levels, and the highest mean concentrations of NNIs and r-NNIs were detected in dormitory samples. Based on the NNI and r-NNI concentrations in the analyzed samples, the mean estimated daily intake values for Chinese adults and children via dietary intake and dust ingestion were 2080-8190 ng/kg bw/day and 378-2680 pg/kg bw/day, respectively.