Abstract
A method for the determination of personal exposure to hydrogen fluoride is described. Samples are collected by permeation through a polyvinyl chloride membrane into a calcium nitrate solution. The collected HF is buffered and determined (as F−) with a fluoride ion selective electrode and the HF exposure (time-weighted-average) is then calculated. The detection limit of the method is 0.001 ppm HF for an eight hour exposure with a working range of 0.05 to 25 ppm. Temperature changes induced a maximum error of ±5.4% over the normal working range (0–46°C). The membrane shields the absorbing solution from contamination from particulates containing metals which could complex the fluoride and cause error. The effects of weak acid formation with the fluoride ion at low pH and possible errors due to hydroxide acting on the electrode at high pH are removed by the addition of a buffer before analysis. A device can be constructed that is small in weight and size and can serve as either an area or personal monitor.