Determination of trace chromium(VI) and molybdenum(VI) in natural and bottled mineral waters using long pathlength absorbance spectroscopy (LPAS).

A liquid core waveguide (LCW) has been used to extend the sensitivity of conventional absorbance spectroscopy for chromium(VI) and molybdenum(VI). Analysis of Cr(VI) and Mo(VI) concentrations in water samples with a 5.0 m pathlength LCW made of Teflon AF-2400 provides 0.2 and 0.6 nM detection limits, respectively. No preconcentration is required in this analysis. The proposed procedures were applied to the determination of chromium(VI) and molybdenum(VI) in natural waters and commercial drinking water. The analytical apparatus is very simple and robust and is amenable to miniaturization and autonomous operation.