Rapid analysis of quinones in complex matrices by derivatization-based wooden-tip electrospray ionization mass...

Quinones are important components participating in various biological processes as well as hazardous substances to human health. Rapid determination of quinones in environmental samples and biofluids is the basis for assessing their health effect. Here, we presented a rapid, straightforward, highly sensitive and environmental-friendly wooden-tip electrospray ionization mass spectrometry (ESI-MS) method for the determination of quinones in PM2.5, urine and serum. An amine group "tag" was introduced to the quinone structure through in situ derivatization with cysteamine to improve ionization efficiency of quinones in wooden-tip ESI-MS. The toothpicks were treated by sharpening and acidification with HNO₃. Experimental parameters, including sample volume, spray voltage, and spray solvent composition were optimized to be 1 μL, 3.5 kV, and ACN/CH₃COOC₂H₅ (v/v, 9:1), respectively. The limits of detection for the determination of 1,4-benzoquinone, methyl-p-benzoquinone, 1,4-naphthoquinone and 1,4-anthraquinone in ACN under the optimal conditions were 1.00, 0.96, 0.13, 0.16 ng (1.00, 0.96, 0.13, 0.16 μg/mL, sample volume, 1 μL), respectively. This approach was successfully applied to the determination of 1,4-naphthoquinone and 1,4-anthraquinone in complex matrices, including PM2.5, urine and serum without or with minimal sample preparation (LOD range: 0.22-1.48 ng).