[Determination of the cysteine residues in the surface-confined biomolecules by using electrochemical desorption and fluorescence detection].

To develop a method for the detection of surface-confined peptides containing cysteine residues or oligodeoxynucleotides (ODNs) whose 3' ends modified with thiol groups, and a thiol-specific fluorescent cross-linker, N-(9-acridinyl) maleimide (NAM) was used. The peptides studied herein include both the oxidized and reduced forms of glutathione, and a hexapeptide (FT). Peptides are first attached onto the activated 11-mercaptoundecanoic acid (MUA)-terminated alkanethiol self-assembled monolayers (SAMs) and then derivatized with NAM. The cysteine residues was determined by using electrochemical desorption and fluorescence detection. GSH concentration as low as 40 pmol x L(-1) can be measured. The fluorescence intensity in the case of FT is about 3 times as high as that for GSH, which is consistent with the molar ratio of cysteine residues in these two molecules. The analytical performance of gene analysis was also evaluated through the analyses of a complementary target and targets with varying numbers of mismatching bases. The method described here is simple, sensitive, reproducible, and does not require sophisticated analytical instrumentation and separation procedures.

[Fingerprinting of Fuzhisan by high-performance liquid chromatography with ultraviolet and evaporative light scattering detector].

OBJECTIVE: To establish a method for fingerprinting of Fuzhisan (FZS, a traditional Chinese medicinal preparation) using high-performance liquid chromatography with ultraviolet and evaporative light scattering detector (HPLC-UV/ELSD) to allow simultaneous determination of 5 major constituents in the preparation. METHODS: HPLC-UV/ELSD analysis was performed on water AlltechC18 column (5 microm, 4.6 mm x 250 mm) with a mixture of acetonitrile (A) and 0.1% acetice acid water (B) as the mobile phase. The solvent A gradient for elution was 0, 12%; 25, 20%; 30, 20%; 75, 30%; 105, 40%; 120, 80%; 130, 12%, with the flow rate of 1.0 ml/min; and the column temperature at 30 degrees . The detective wavelength was 335 nm, drift tube temperature was 80 degrees , pressure of nebulizer gas was 25 psi. The similarities between the HPLC-UV/ELSD fingerprints of the 12 extracts were calculated using similarity evaluation software. RESULTS: The fingerprint of FZS was established and the 5 major constituents were identified. The complementarity between the fingerprints of UV and ELSD was analyzed, showing good correlation between 12 batches of FZS. CONCLUSION: The method for fingerprinting can simultaneously characterize the main chemical constituents in FZS and allows stable, effective and comprehensive quality control and evaluation of FZS for a single sample.