Several factors influence the precision of laser-induced breakdown spectroscopy (LIBS) measurements. This paper reports on the effect of emission signal temporal development, sample translational velocity, number of spectra accumulated, laser pulse stability, detector gate delay, surface roughness, and use of background correction on LIBS precision. The results are presented in two formats: within measurement/shot-to-shot precision (intra-measurement) and between measurement precision (inter-measurement). The data indicate that intra- and inter-measurement precision are optimized under different conditions. The best precision obtained was 0.03%.
A quercitrin rich vegetal flavonoid sample was fractionated using a new hydrodynamic CCC apparatus based on the It0 scheme IV design. The Kromaton CCC apparatus has two spools with a tube coiling allowing work with two different apparatus volumes. The small "analytical" volume was 94 mL and the large "preparative" volume was 1.07 L. The fractionation of the flavonoid sample was done using the two machine volumes. The bi phasic liquid system was a non chlorinated solvent system, butanonelwater. W detection was possible at 330 nm. In one run, 330 mg of the flavonoid sample could be fractionated by the CCC machine in six peaks that were collected in nine fractions. 3003 Copyright 0 1998 by Marcel Dekker, Inc. www.dekker.com Downloaded by [Erciyes University] at 22:57 02 January 2015 3004 BERTHOD ET AL.The HPLC and MS analysis of the fractions allowed identification of the main constituents of the sample. Quercitrin, a rhamno-flavonoid, was the major compound making up more than 88% wlw of the studied sample. The three minor identified flavonoids were quercetin, kaempferol, and kaempferol-3-rhamnoglucoside. Six very minor impurities were detected by the HPLC analysis of the fractions, but they were not unambiguously identified.
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