A sensitive surface enhanced Raman spectroscopy (SERS) substrate based on SiO2@Ag core-shell with a QuEChERs pretreatment method were constructed for the determination of carbendazim residue in tobacco leaves. The SERS substrate was formed by self-assembly of monolayer homogeneous SiO2 nanospheres onto silicon wafer following by vacuum thermal evaporation of silver film. The QuEChERs pretreatment method was used to eliminate the interfering effects of pigments and organic acids in tobacco leaves. The results for carbendazim in tobacco leaves show the limit of detection (LOD) of the SERS substrate was 0.1 mg/kg and the recovery rate was from 82.56% to 95.93%. The proposed low-cost sensitive SERS substrates provide potential application for tobacco safety monitoring.
Carbazole derivatives (CZDs) are an important class of nitrogen-containing heterocyclic compounds which have been widely used in photoelectric materials, dyes, medicine, supramolecules and other fields. The ecological risks of CZDs released into environment during the production and product utilization have gradually attracted people's attention. However, for the lack of analytical methods of CZDs in environment, the levels of CZDs entering the environment remain unclear. Herein, an analytical methodology for simultaneous measuring 13 CZDs associated with photoelectric materials in sediment samples has been established by using ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) in combination with a QuEChERS pretreatment technique. The parameters of the sample pretreatment and UHPLC-HRMS analysis were optimized. The established method was validated by evaluating its recovery, accuracy, matrix effect, limits of method detection (LODs), and so on. The instrument detection exhibits a linear response within concentration range of 1 to 1000 µg/L, and the LODs were ranged from 0.005 to 0.165 µg/kg. The average recoveries for the majority of CZDs were in the ranges of 82.9% ∼ 107.0% (spiked level 25 µg/kg), 74.1% ∼ 114.5% (spiked level 10 µg/kg) and 53.3% ∼ 123.7% (spiked level 2 µg/kg), respectively, and the relative standard deviations of all spiked levels were between 0.47% and 11.30%. The developed methodology was applied to the analysis of twenty sediment samples. A CZD of 2-methoxycarbazole (2-MOCZ) has been firstly detected in the sediments with the concentration up to1.4 µg/kg, indicating the environmental occurrence of CZDs and alerting to their potentially ecological risks in the environment.
危险品化学品经营许可证（带存储）