A novel fully automated on-line coupled liquid chromatography–gas chromatography technique used for the determination of organochlorine pesticide residues in tobacco and tobacco products

• A novel fully automated on-line coupled LC–GC technique is reported.
• A switching valve is used to isolate the pre-column and analytical column.
• This technique can completely remove the LC solvent and is suitable for the MS.
• The GPC is used to simplify the sample pretreatment for the OCPs analysis.
• The new method exhibits high sensitivity and good recoveries.

In this study, a novel fully automated on-line coupled liquid chromatography–gas chromatography (LC–GC) technique was reported and applied for the determination of organochlorine pesticide residues (OCPs) in tobacco and tobacco products. Using a switching valve to isolate the capillary pre-column and the analytical column during the solvent evaporation period, the LC solvent can be completely removed and prevented from reaching the GC column and the detector. The established method was used to determinate the OCPs in tobacco samples. By using Florisil SPE column and employing GPC technique, polarity impurities and large molecule impurities were removed. A dynamic range 1–100 ng/mL was achieved with detection limits from 1.5 to 3.3 μg/kg. The method exhibited good repeatability and recoveries. This technology may provide an alternative way for trace analysis of complex samples.