Flow analysis for determination of inorganic arsenic and antimony in seawater with on-line liquid nitrogen trap and hydride generation

An automatic flow analysis system with on-line liquid nitrogen trap,hydride generation and flame-less atomic absorption spectrophotometry was presented for the determination of inorganic arsenic and antimony in seawater.The experimental conditions such as acidity of reduction reaction,the amount of sodium borohydride,the flow rate of carry gas (high purity of nitrogen) were tested and selected optimally.The limit detection of the method presented was 0.15 ug/L for arsenic and 0.24 μ/L for antimony.During the determination of seawater samples with levels microgram arsenic and antimony pa litre the variation coefficient would be ±4% for arsenic and ±10% for antimony.The volume needed for one measurement was 9 mL for arsenic and 12 mL for antimony.The frequency of sample determination reached 20 times per hour for arsenic and 15 times per hour for antimony.