Determination of Ultratrace Amounts of Copper and Cadmium in Seawater by Graphite Furnace Atomic Absorption Spectrometry with Flow-Injection Semi On-line Preconcentration

✍ Scribed by M.H. Wang; A.I. Yuzefovsky; R.G. Michel

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 827 KB
• Volume: 48
• Category: Article
• ISSN: 0026-265X
• DOI: 10.1006/mchj.1993.1106

✦ Synopsis

Methods are described for the determination of ultratrace amounts of copper and cadmium in seawater by graphite furnace atomic absorption spectrometry with flow-injection, microcolumn preconcentration. A new type of (\mathrm{C}{18}) column loaded with sodium diethyldithiocarbamate (sodium-DDC) was used to extract copper and cadmium from seawater as the DDC chelates. The analytical effects of the (\mathrm{pH}) of the mixture of the sample and sodiumDDC solutions and the concentration of the chelating reagent were studied. Sodium-DDCloaded columns and unloaded (\mathrm{C}{18}) columns with different shapes and volumes were compared. To determine copper in seawater, a simple aqueous calibration was made with a mixture of palladium and magnesium nitrate as a matrix modifier, while for cadmium no matrix modifier was necessary. This method required only small seawater volumes, 600 and (400 \mu) for the determination of copper and cadmium respectively, with preconcentration factors of 15 -fold for copper and 10 -fold for cadmium. Detection limits for the preconcentration of aqueous solutions of copper and cadmium were 0.024 and (0.004 \mu \mathrm{g} \operatorname{liter}^{-1}(3 \sigma)), respectively. Results for determinations of copper and cadmium in National Research Council of Canada, CASS-2, Nearshore Seawater Reference Material showed no significant differences between the certified values and the measured values, based on Student's (t) test at the (95 %) confidence level. The relative standard deviations of the various measurements varied between 2 and 8%. O 1993 Academic Press, Inc.