ABSTRACT
In this study, a neutral desorption-extractive electrospray ionization mass spectrometry ( ND-EESI-MS) method was developed for the direct and rapid detection of dichlorvos ( DDVP) in honey samples without any sample pretreatment procedure. Under the positive ionization mode, the main characteristic parent ion of DDVP was m/z 223 (MW:222) and daughter ions were m/z 109 and m/z127. Under the optimized working conditions, with the signal intensity of m/z 127 as quantitative index, the quantitative information of DDVP residues in honey was acquired effectively. The results showed that the linear range of DDVP for spiked honey was 5-1000 ng/mL (R2=0. 998) with the limit of detection (LOD) of 1. 0 ng/mL (n=3) and the recoveries for the DDVP spiked honey samples at the concentration levels of 10 , 30 and 400 ng/mL were 93 . 0%-103. 0%, with the relative standard deviations (RSDs, n=6) of less than 4. 4%. Meanwhile, for detection of spiked honey with gas chromatography-flame photometric detector ( GC-FPD ) , the linear range was 5-1000 ng/mL (R2=0. 999) with the LOD of 1. 6 ng/mL(n=3), and the recoveries of DDVP at the spiked honey concentration levels of 10 , 30 and 400 ng/mL were 94 . 9%-110 . 3%, with the RSDs of less than 7. 6%.
ABSTRACT
Liquid-assisted surface desorption atmospheric pressure chemical ionization mass spectrometry (LA-DAPCI-MS)was used directly for the analysis of healthy rat liver (normal control group);acute alcoholic injury rat liver(alcohol model group)and Zhizi Dahuang decoction-treated rat liver (ZZDHD group)sections with the mass spectrometry images obtained simultaneously.Principal component analysis (PCA)was employed for the differentiation of livers of the groups;and 3 phospholipids;PC (34 ∶2);PC(36 ∶4)and PC(38 ∶4);were found to be the main factors.LA-DAPCI mass spectrometry images showed that the 3 phospholipids were evenly distrib-uted in liver under the spatial resolution of 0.01 mm2.Contents of 3 PCs in the model group were decreased in alcohol model group compared to the normal control group and the ZZDHD group;which revealed the relationship between acute alcoholic liver injury and intrahepatic phospholipid variation.The results showed that ZZDHD had protective effect on acute alcoholic liver injury-induced intrahepatic phospholipid variations at the molecular level.