MECHANISM OF VAPORIZATION OF SULFUR IN ELECTROTHERMAL VAPORIZATION INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

The mechanism is reported of the vaporization of sulfur using electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS). Studied were the vaporization characteristics of sulfuric acid, thiourea, potassium sulfate, ferric sulfate and magnesium sulfate. All compounds with the exception of potassium sulfate released sulfur as SO, gas resulting from thermal decomposition of sample. Potassium sulfate vaporized without decomposition. The use of KCI, KNO3 and KOH as chemical modifiers was studied, with KOH being the most beneficial for the ETV-ICP-MS determination of sulfur. The absolute limit of detection for sulfur was 13 pg which corresponds to a relative limit of detection of 0.26 ng ml(-1) using a 50 mu l sample.