Table. II.
Element T _ h_
Lu Y Ce(II1) Cr(I1I) Zr
La sc Cr(V1) Er Tb Sm Pt(V1) Ti
Extent of Interference Various Elements
of
pg. of Oxide In interfering range Equivalent to equiv. to 0.0003 1 pg. Be pg. Bea
6 X 102“
7 X iozh 7 x 102b 2 x 10% 2 x 103s 5 x lo’* 5 x 103h 7 x 103*
x x 2 x 2 x 7 x 1 1
5
3
x x
loa? 104~ 104~ lodr 104~ 104d 10k
1
0.7 0.5 2 10 5 8 8 50 20 20 10 150 125 250 150 250
UWI) e Fe Bi d Tliese amounts in final 25 ml. give an absolute error equivalent to &0.0003 pg. Be; this error is less than 1 p.p.m. of beryllium based on a 500-pg. sample. * Element fluoresces. c Depresses fluorescence. White precipitate forms. e Interference variable, depending on standing time and temperature. cium, cobalt, copper, pallium, germanium, indium, lead, magnesium, manganese, mercury, molybdenum, nickel, selenium, tin, tungsten, vanadium, and zinc. Antimony(II1) and (V) do not interfere at levels up t o 200 pg. of the oxides; higher concentrations were not tested. Table I1 summarizes the data. for the interfering cations. A direct relation does not always exist
between corresponding values in columns two and three of this table, because for some elements the estent of interference is not directly proportional to concentration. A check was also made of anions significant in rock analysis. The anions were added as sodium salts. KO interference was given by 1 mg. of SiO,, by borate equivalent to 10 nig. of B*Oa, by 20 mg. of perchlorate, 20 mg. of sulfate, 20 mg. of nitrate, 1 nlg. of fluoride, and 2 ing. of bromide. Tartrate reduces the fluorescence of the beryllium complex; 40 mg. of tartrate resulted in a 20% reduction in the net fluorescence with 0.1 pg, of Be. Analysis of Low Grade Ores. The results on 10 samples are compared in Table I11 with those obtained spectrographically. T h e samples contained bertrandite and beryl as the beryllium minerals. In general the agreement is good. ACKNOWLEDGMENT
The filter system was selected on the basis of previous studies made by Mary H. Fletcher of this laboratory and a t her suggestion. The spectrographic determinations (Table 111) were made b y a group supervised by -4rmill Hele of this laboratory. LITERATURE CITED
Table 111. Comparison of Fluorometric with Spectrographic Results
75 Be Spectrographically Fluorometric=
