Micro-solid phase extraction with helical-solid-sorbent in the presence of organic solvent for gas chromatography–mass spectrometry analysis of per-O-methylated mono- and disaccharides

A new method for the analysis of mono- and disaccharides by gas chromatography–mass spectrometry (GC–MS) has been developed. The analysis uses per-Omethylation of analytes and dynamic micro-solid phase extraction with helical sorbent as sample preparation steps. The two-phase (solid–liquid) extraction rate of per-O-methylated carbohydrates was not affected by the stirring rate of the sample solution. The rate-limiting process was the diffusion of per-O-methylated carbohydrates in polydimethylsiloxane (PDMS) sorbent. The amount of per-O-methylated carbohydrates extracted was significantly increased by the addition of a few drops of a solvent such as dimethyl sulfoxide, benzene, or chloroform. A new three-phase (solid–liquid–liquid) extraction technique, which increased the efficiency of extraction by more than 50 times, was developed. The micro-solid phase extraction with a helical sorbent was examined for its applicability to the analysis of mono- and disaccharides from a synthetic mixture and from orange juice. The reproducibility was found to be approximately 2% when the extraction and injection were performed with a special helical sorbent holder device. The linearity was found to be very good up to 0.3 mg/mL. The limit of detection (LOD) was up to nanograms per milliliter, depending on the organic solvent present in solution.