A green, sensitive, and accurate method was developed for the extraction and determination of bromophenols (BPs) from aquatic products by using organic solvent-free gas purge microsyringe extraction (GP-MSE) technique in combination with stable isotope labeling (SIL) strategy. BPs were extracted by NaHCO buffer solution, with recoveries varying from 92.0% to 98.5%. The extracted solution was analyzed by SIL strategy, during which analytes and standards were labeled by 10-methyl-acridone-2-sulfonyl chloride (d-MASC) and its deuterated counterpart d-MASC, respectively. The labeling reaction was finished within 10 min with good stability. The liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) sensitivity of BPs was greatly enhanced due to the mass-enhancing property of MASC, while the matrix effect was effectively minimized by the SIL strategy. The limits of detection (LODs) were in the range of 0.10-0.30 μg/kg, while the limits of quantitations (LOQs) were in the range of 0.32-1.0 μg/kg. The proposed method also showed great potential in the qualitative analysis of other bromophenols in the absence of standard.

A new stable isotope labeling (SIL) reagent pair, 10-methyl-acridone-2-sulfonohydrazide (MASH) and its deuterated counterpart d-MASH was synthesized and successfully applied to the analysis of perfluorinated carboxylic acids (PFCAs) in serum samples. The limits of detection (LODs) were in the range of 0.07-0.42μg/L, and the limits of quantitation (LOQs) were in the range of 0.25-1.38μg/L. Besides ionization enhancing effect, MASH also showed excellent fluorescence property. Therefore, the mass spectrometer operation cost was greatly lowered by carrying out parameter optimization experiments on HPLC which is easier to operate and maintain. The SIL strategy was confirmed to be effective in reducing matrix effect. The developed multiple-reaction monitoring (MRM) condition of PFCAs was also suitable for other carboxylic acid due to the introduction of MASH which is more prone to fragmentation than the analytes. With the MRM conditions obtained from PFCAs, fatty acids were also found in serum samples. This feature made the proposed method show powerful potential in the identification of acidic compounds in complex samples in the absence of corresponding standard.

No abstract

No abstract