PubMed · 10739186
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
J Ruzicka, E H Hansen. 2000-03-01. Flow injection analysis: from beaker to microfluidics.. https://doi.org/10.1021/ac002756m
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
The coupling of sequential injection analysis and optosensing has been developed for the first time. It has been applied to the determination of labetalol in both pharmaceuticals and urine samples, with the analytical signal (native fluorescence) being monitored directly on sensing zone microbeads. The solid support used was the nonionic silica gel C18, using 20% methanol-water (v:v) as a carrier. By using a 1.5-ml sample volume, we achieved a detection limit of 3.3 ng ml-1. This sensitivity allowed the determination of the compound in urine samples. A recovery study was carried out at the labetalol levels usually found in urine after pharmaceuticals administration, and recovery percentages close to 100% were obtained. The relative standard deviation was 3.4% for 100 ng ml-1 labetalol. No pretreatment was needed for urine samples, only an appropriate dilution, therefore minimizing the time required per sample analysis. In addition, the determination of the analyte was also carried out in one pharmaceutical, with a satisfactory result being obtained.
Two modes of liquid-liquid extraction in flow-injection systems were compared and applied to the fluorimetric determination of thiamine (Vitamin B(1)). The first included phase segmentation, but fluorescence was measured without phase separation. In this mode, thiamine was detected at concentrations higher than 8 microg/l with a linear application range of 30-2,000 microg/l, an R.S.D. of 1.9% (150 microg/l, n=10) and a sampling frequency of 60/h. In the second mode, a single segment of organic solution was injected into the aqueous stream and fluorescence was also measured without phase separation. Using this mode, concentrations of thiamine higher than 1 microg/l were detected, with a linear application range between 5 and 280 microg/l, an R.S.D. of 2.4% (150 microg/l, n=10) and a sampling frequency of 60/h. The two forms were applied to the analysis of thiamine in pharmaceuticals.
A novel approach to real-time monitoring of protein immobilization resulted in the surprising finding that current immobilization protocols are far from optimized.