Microextraction on a screw for determination of trace amounts of hexanal and heptanal as lung cancer biomarkers.

Solid phase microextraction on a screw was utilized for the extraction of hexanal and heptanal as lung cancer biomarkers from urine samples. Reduced graphene oxide (rGO) was coated on the surface of a stainless-steel set screw by electrophoretic deposition method. The screw was located inside a glass cover, and the created channel acted as the sample solution flow pass. A 5 mL glass syringe was connected to a syringe pump to direct the sample and the eluent through the channel. The extraction procedure was followed by gas chromatography/mass spectrometry (GC/MS) for separation and determination of the extracted aldehydes. The effective parameters on the extraction efficiencies of the analytes were identified and optimized. Under the optimal extraction conditions, the extraction time was as short as 10 min. The calibration curves indicated good linearity (R2 > 0.97) within the concentration range of 1.0-50 μg L-1. The obtained limits of detection (LODs) for hexanal and heptanal were down to 0.4 and 0.3 μg L-1, respectively. Considering the repeatability, simplicity, and eco-friendliness of this simple extraction method, it can be efficiently used for preconcentration of aldehydes in different samples.