Development of headspace solid-phase microextraction with on-fiber derivatization for determination of hexanal and heptanal in human blood

Hexanal and heptanal in human blood have been regarded as potential biomarkers of lung cancer. Owing to their high volatilities and activities, it is difficult to accurately measure the two biomarkers. In the current work, headspace solid-phase microextraction (HS-SPME) with on-fiber derivatization technique was developed for quantitative analysis of hexanal and heptanal in human blood. In the proposed method, the two aldehydes in blood were headspace extracted by using a poly (dimethylsiloxane)/divinylbenzene (PDMS/DVB) fiber with O-2,3,4,5,6-(pentafluorobenzyl) hydroxylamine (PFBHA) at 60 °C for 8 min. The aldehyde oximes formed on the fiber were desorbed and analyzed by gas chromatography–mass spectrometry (GC–MS). The method validations including detection limit, recovery and precision were studied. It was found that the method provided low detection limits of 0.006 nM for hexanal and 0.005 nM for heptanal, recoveries from 89% to 95% and R.S.D. values less than 8.5%. The present method was applied to quantitative analysis of hexanal and heptanal in normal blood and lung cancer blood. Hexanal concentrations from 7.33 to 15.23 μM and heptanal concentrations from 2.47 to 9.23 μM were found in the lung cancer blood, while both hexanal and heptanal in the control blood were lower than 0.6 μM. This further demonstrated that hexanal and heptanal might be the biomarkers of lung cancer. The experimental results showed that GC–MS and HS-SPME with on-fiber derivatization is a simple, rapid, sensitive and solvent-free method for determination of in hexanal and heptanal human blood.