V O L U M E 2 6 , NO. 4, A P R I L 1 9 5 4
767
RESULTS
The fluorine content of a sample of tea as determined by the present method was 180 p.p.m., whereas the values obtained by the conventional ashing method ranged from 30 to 120 p.p.m., depending on the temperature of ashing, period of ashing, the fixative, and the quantity of the fixative employed. The method is now being extended to other biological materials,
sity of Minnesota for advice and for assistance in preparation of the manuscript. LITERATURE CITED
Remmert, L. F., ANAL.CKIEM., 25, 450 (1953). (2) Smith, F. A., and Gardner, D. E., U. S. Atomic Energy Commission, Unclassi8ed Document UR 36 (1948). (3)
Willard, H. H., and Winter, 0. B.. IND.ENG.CHEM.,ANAL.ED., 5.7 (1933).
(4) Venkateswarlu, P., and Narayana Rao, D., Indian J . Med. Research, 4 1 , 4 (1953).
ACKNOWLEDGMENT
The authors are indebted t o ITr.D. Armstrong of the Univer-
RECEIVED f o r review September 12, 1953. Accepted January 14, 1954.
Spect rochemical St udy of Gravimet ric Procedure For Barium, Strontium, and Calcium P. R. WILKINSON and J. A. GIBSON, JR.,
Department of Chemistry, W e s t Virginia University, Morgantown, W. Va., and
A. J. W. HEADLEE, W e s t Virginia Geological Survey, Morgantown, W . V a .
G
RAVIMETRIC methods for the separation and determination of barium, strontium, and calcium have been adequately reviewed by many authors (6, 8) and no further attempt a t review is made here. Previous work has indicated that the agreement of the results obtained by the various procedures is often largely through a compensation of errors and that changes in the concentration of any one of the constituents of a mixture of alkaline earths may affect the separation of the others. This investigation was originated because of the great variation between the chemical and spectrochemical analysis when both synthetic and chemically analyzed standards are used as spectrochemical standards. Material balance studies made with the aid of spectrochemical analyses offer a method for determining the merits of a gravimetric procedure. It is possible to determine the amount of coprecipitation and the losses due to solubility. The effectiveness of different precipitating agents and variations in procedure may be studied and evaluated. The material balance values represent a correction of the gravimetric results for inherent errors. EXPERIMENTAL
Table I.
Reagent Purity Determinations as Per Cent of Reagent Anion
Reagent CaCOa (special) BaCOs (purified) BaCOa (impure) SrCOs (anal.) Ba(NOa)p (anal.) Sr(NOa)z (anal.) SrSOd (purified) BaCrOI (purified) Blank (solids)a a Blank determination of amounts usrd.
Ba
