Simultaneous multielement determination in microliter samples by rapid-scanning spectrometry coupled to a microwave-induced plasma

A modified electrothermal atomizer is coupled to a helium microwave-induced plasma (m.i.p.) for atomic emission spectrometry. For preliminary evaluation, this arrangement was coupled to a monochromator to quantify single elements in microliter samples. Detection limits range from 3 to 25 pg for Cd, Fe, Pb, Mn and Au and linear dynamic ranges are 2–4 orders of magnitude. The monochromator, fitted with a rapid scanning galvanometer mirror, is also used as a multielement detector. A spectral window of ca. 40 nm is rapidly scanned (10 Hz) across the exit slit and five elements from one solution are determined in rapid sequence. In the multielement mode, the detection limits are in the range 50–250 pg, as might be expected, owing to the decreased duty cycle. However, there is a significant improvement when compared to an earlier report from this laboratory. By narrowing the spectral coverage and taking data more rapidly this drawback is minimized.     

Application of a rapid scanning plasma emission detector and gas chromatography for multi-element quantification of halogenated hydrocarbons

A microwave induced plasma emission detector is used as an element-selective detector for gas chromatography. The spectrometer, which is fitted with a rapid scanning galvanometer mirror, is used to scan a pre-selected spectral window to provide information in the multi-element mode. This information is used to determine the per mole response of some elements as a function of molecular structure. Despite the low microwave powers employed, the response per mole appears to be independent of the molecular structure. Detection limits and linear dynamic ranges are determined by narrowing the spectral coverage to increase the sensitivity. Calibration curves are linear over several orders of magnitude and detection limits are at the pg/sec levels.