Biomedical subjects

Shi-hua Fan

Publications and source records attributed to Shi-hua Fan.

2 recordsLinked to original sources

PubMed2005

[Determination of nitrite in water samples by sequential injection analysis with chemiluminescence detection on chip flow cell].

A sequential injection chemiluminescence's system using a chip flow cell was described for the determination of trace amount of nitrite in water samples. Nitride reacted with hydrogen peroxide to form peroxynitrous acid in sulfuric acid medium, which was an unstable in acid medium and subsequently was quenched into peroxynitrite in basic solution. During the composition of peroxynitrite the chemiluminescence intensity was enhanced with the presence of uranin and ethyldimethylcetylammonium bromide. The reaction coil (flow cell) and holding coil was combined for tracking the emission signal. The experimental parameters including physical and chemical parameter were optimized. The interference of cations in water samples was eliminated by passing previously the sample solution through a cation-exchange column. The linear range of the calibration graph was obtained from 1 x 10(-6) to 1 x 10(-4) mol x L(-1) with a correlation coefficient of 0.9998. The detection limit at 95% confidence was 6.8 x 10(-7) mol x L(-1). The relative standard deviation at 1 x 10(-5) mol x L(-1) nitrite level was 2.7%, and the recovery of 90%-99% and the sampling frequency of 80 h(-1) were obtained.

Calcium↗

PubMed2004

[Studies on sequential injection spectrophotometric system using a reflective flow cell for process analysis].

A reflective flow cell was developed and coupled to a sequential injection system and optical fiber photometric detection system based on emitting diode light source. A multistrand bifurcated optical fiber was coupled with incident light, detector and flow cell. Optical fibers were used to carry light from the electronics unit to a reflective flow-through cell and back. The liquid flow path through the cell is linear with a large exit aperture such that bubbles are not trapped in the optical path. The optical arrangement is such that the incident light crosses the liquid flow orthogonally and is reflected back to the receiver fiber. This arrangement reduces the reflective index sensitivity by an order of magnitude relative to a conventional flow cell. The cell showed good immunity to refractive index and air bubble effects. The chromogenic reaction of chloride ion with mercury thiocyanate-iron(III) was used as a model reaction to optimize the experiment system and check the optical system. The reflectance of the reaction was monitored with blue emitting diode. The linear range was 0-100 mg x L(-1) Cl-. A detection limit (3sigma) of 1.2 mg x L(-1), precision of 1.5% (n = 11), and a throughput of 30 samples per hour were achieved.

English Abstract↗