This paper describes a reliable emission spectrographic method capable of quantitatively determining boron in the 0.5 to 50 ppm range. The detection limit for the method is 0.1 ppm. Previous to this report no reliable method was available for the accurate determination of boron in reagent 40% ammonium fluoride solution in the ppm range; consequently, no incoming inspection or manufacturer's certification was available for boron content. Analysis of representative ammonium fluoride samples shows that the boron level is less than 0.1 ppm, suggesting that this element may not be a major problem in ammonium fluoride reagent.
MOS grade designates a better than reagent grade purity material used in the electronic industry.
3.
ParkesG. C., Mellor Modern Inorganic Chemistry (London, 1967), p. 742.
4.
All decomposition, melting point and boiling point temperatures were obtained from WeastR. C., Handbook of Chemistry and Physics50th ed. (Cleveland, 1970).
5.
Detection to this limit was established by running four 0.1 ppm standards and visually comparing them to a blank.
6.
Use all plastic ware for preparation and storage of these solutions.
7.
In NH4F solution, boric acid reacts on heating to yield NH4BF4, the form in which the boron, if a contaminant, should be present.
