Direct Determination of Cadmium in Urine by Electrothermal Vaporizer-Inductively Coupled Plasma Analysis Using a Tungsten Coil Vaporizer

摘要

Since their introduction, tungsten coils (W-coils) have been used as electrothermal atomizers in atomic absorption spectrometry, atomic emission spectrometry (AES), and atomic fluorescence spectrometry, and as electrothermal vaporizers (ETV) for the inductively coupled plasma (ICP). The power requirements to reach vaporization temperatures in the 3300 K range are minimal (150 W), and the devices do not require water cooling. The W-coil is therefore an ideal vaporizer for portable spectrometers, and it is easily attached to standard ICP instrumentation. An array of clinical, biological, and environmental sample types has been analyzed using W-coil devices. Complicated sample matrices usually require special calibration techniques such as the standard addition method or the use of matrix-matched standard solutions. While matrix modifiers have been used to some extent with W-coil devices, the mechanisms of action of the modifiers are not well understood, and the technique is not as successful as it is with the graphite furnace. This work reports the analysis of urine samples after simple aqueous dilution by W-coil ETV-ICP-AES. The combination of the internal standard and standard addition methods provides accurate and precise data without the need for matrix modifiers or acid digestion.