TRACE-ELEMENT DETERMINATION OF MERCURY BY TOTAL-REFLECTION X-RAY-FLUORESCENCE

A rapid and simple method is presented for the determination of trace amounts of ionic mercury in solutions by total-reflection X-ray fluore scence. The method relies on the formation of a mercury amalgam on a 5 0 nm thick silver coating deposited on a specular-surface quartz refle ctor. Quantification of Hg in dilute HNO3 solutions is achieved, with a straight calibration line in the concentration range 50-350 ng ml(-1 ). With excitation by a molybdenum anode X-ray tube at 40 kV and 20 mA , the limit of detection achieved for a 2 cm(3) specimen with 1000 s c ounting time is 15 ng ml(-1). (C) 1997 Elsevier Science B.V.