Biomedical subjects
Publications and source records attributed to Ya-feng Guan.
Solid-phase microextraction (SPME) is a technology with functions of sampling, extraction and concentration based on adsorption/absorption-desorption equilibrium between coating and sample. The recent development of SPME is reviewed. Studies on the in-tube-SPME technology, novel extraction probes and its coupling with other analytical technologies are summarized.
A portable laser-induced fluorescence detector, based on confocal configuration detection system has been developed. This is assembled from commercially available components. All the components of the detector are domestic, which makes it low cost. The routine alignment procedure is simplified by using a skillful and visual alignment system and requires minimal experience for operation. The module design makes it possible for high performance liquid chromatographic, capillary electrophoretic and microfluid chip applications. The performance of the detector, including the sensitivity, noise, linear range and detection limit, was evaluated by capillary electrophoresis and flow injection analytical technique using a red-absorbing cyanine derivative (Cy5) and Cy5 labeled tryptophan as test samples. The results show that the background signal is very low and the peak-to-peak noise level is 0.002 mV. The detection limit and the linear dynamic range are 3.7 nmol/L and 10(3), respectively.
A simple and efficient method based on the technique of capillary column switching-back flushing was developed for the detailed analysis of aromatic hydrocarbons in gasoline. The early eluting components from a pre-column and the components of interest eluting from an analytical column are all directed to a flame ionization detector through a tee piece, which facilitates the quantitation of aromatic hydrocarbons in gasoline by normalization method. Real samples were analyzed and RSD < or = 3%. The operation is simple and easy, and the switching time window is +/- 5 s.