Metal speciation in the ppt range by HPLC and diode laser atomic absorption spectrometry in a flame

A simple, compact, and powerful instrument for metal speciation in the ppt range is described. The instrument includes a HPLC module for separation an d a diode laser for element-selective detection by wavelength modulation ab sorption spectrometry in an analytical name. The high detection power for m etal species is due to a two-beam arrangement with logarithmic amplificatio n of the normalized signal, which compensates the laser residual amplitude modulation noise, the offset, and its fluctuation, The analytical figures o f merit are demonstrated by measurements of very low concentrations of Cr(V I) in tap water.