Method for decreasing the atomic-absorption sensitivity of calcium using the calcium 430.3-nm non-resonance line

Abstract

A simple method of reducing the atomic-absorption sensitivity for calcium approximately 600 times by using the calcium 430.3-nm non-resonance line is described. It is essential to use a dinitrogen oxide-acetylene flame in order to achieve a sufficient population of calcium atoms in the lower energy state of the 430.3-nm line. In order to minimise the effect of the calcium flame emission at 430.3 nm, the hollow-cathode lamp was run at maximum current. An almost linear calibration graph was observed up to an absorbance of 1.0, which indicated little self-absorption and/or self-reversal of the 430.3-nm line. Recovery tests on some typical sewage sludges and presshouse return liquor digests were carried out and satisfactory results were obtained.