Liquid chromatogram peak storage and analysis by atomic absorption spectrometry

Fingerprinting inorganic arsenic and organoarsenic compounds in in situ oil shale retort and process waters using a liquid chromatograph coupled with an atomic absorption spectrometer as a detector

“…We believe this to be the first positive molecular characterization of any trace inorganic or organometallic substances in such fossil fuel recovery products. Since the HPLC-GFAA technique is shown to be broadly applicable to a wide variety of elements in many molecular classes, with great freedom from usual matrix interferences (8)(9)(10)(11)(12)(13)(14), we envision similar utility for speciating other toxic metal-containing molecules in oil shale products. Among these prospects, mercury, selenium, and lead are important because of their known biotransformations (25) and presence in kerogen pyrolysates (5,30,31).…”

“…Additionally, each setup had an Altex 153 ultraviolet detector, which was used at 254 nm to monitor the organic matrix and to measure solvent fronts (f0). Experimental parameters for coupling the HPLC to the GFAA detector, and optimization of arsenic speciation, have been previously described (8)(9)(10)(11).…”

“…Chromatographic Procedures. Several available (11) gradient compositions were used for the HPLC speciation of arsenicals in the basic (pH ~9.2) retort and process waters, a very effective combination being that of a commercial anion-exchange column (Dionex) with an eluent composition recommended by Woolson and Aharonson (14). This method used a step gradient starting 10 min after injection from 100% water-methanol (80:20 v/v) to 100% 0.02 M (NH4)2C03 in water-methanol (85:15 v/v) at 5% min™1, with a flow rate of 1.2 mL min™1.…”

“…Recent advances, since the introduction (8) of a highperformance liquid chromatograph (HPLC) automatically coupled to a graphite furnace atomic absorption spectrometer as a detector (GFAA), permit element-specific characterization of environmentally important trace inorganic and organometallic compounds. These advances provide an effective tool that allows direct separation and identification of these types of compounds in oil shale process products (8)(9)(10)(11)(12)(13)(14). In this paper, we report the successful use of two HPLC-GFAA units (10), in our re- CO air/stream a 0 Field retorting temperatures are not accurately known because of corrosion problems with thermocouples.…”

On-line sample pre-treatment systems interfaced to electrothermal atomic absorption spectrometry†

“…To increase sample throughput, the sampling procedure was modified to store the chromatographic peaks temporarily and thus be able to analyze multicomponent mixtures of organometallics of the same metal or multi-element, multicomponent mixtures. 94 These sampling modes have been successfully demonstrated for the speciation of organocompounds of arsenic, 28 lead, 94 tin, 30,95 selenium, 25,96 etc. However, flow control and gradient elution cause background signal fluctuations owing to molecular absorption.…”