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General Suitability. Standards for flame photometry are reported to be generally suitable. The number of laboratories using the technique, particularly for inorganic chemicals and metals and alloys, was significantly large. I n no case was there a significant percentage of unfavorable reports. Availability. About 7 5 % of the laboratories reporting found standards for flame photometry readily available. I n the analysis of metals and alloys and inorganic chemicals, the percentage of favorable replies was somewhat lower, particularly for the concentration range of 0.001 tol%. Accuracy. About 7 5 % of the replies were favorable with respect to accuracy. Cost. A quite large majority of the laboratories, 8 0 % or greater, were satisfied with regard to cost of standards. Summary. F l a m e photometry is a widely used technique over the entire concentration range. The number of laboratories reporting on this technique was so large t h a t the status of standards with respect to this technique can be assessed quite well. Although a general assessment would be t h a t standards are generally quite suitable for this technique for all categories listed, some improvement is needed, particularly with respect to accuracy in the low concentration ranges— < 1 0 ppm. FLUORESCENCE AND/OH PHOSPHORESCENCE
BIO-RAD Laboratories Dept. A 32nd & Griffin Ave. Richmond, Calif. 94804
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cycle No. 19 on Readers' Service Card 30 A
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ANALYTICAL CHEMISTRY
General Suitability. The number of reporting laboratories using this technique was quite small. F o r the analysis of < 1 ppm of pesticides, two of the four laboratories reported favorably. For pharmaceuticals in the concentration range of 10—100 ppm, three of five laboratories reported favorably; metals and alloys a t 10 p p m or less—about 7 5 % of the laboratories reported favorably. I n general, about half of the laboratories t h a t used this technique reported favorably as to general suitability. Availability. Considerably more
t h a n one half of the laboratories found standards generally available for this technique. This statement pertains to all concentration ranges. Accuracy. A majority of the laboratories reported favorably as to the accuracy of s t a n d a r d reference materials for this technique. However, it should be pointed out t h a t in no category was there complete satisfaction as to accuracy. Cost. A significant majority of the laboratories reported favorably with respect to cost. Summary. Although the sampling of laboratories is not large, it is pertinent to note t h a t there is a definite unfavorable comment with respect to standards for this technique. G A S CHROMATOGRAPHY
General Suitability. For inorganic chemicals, about 6 0 % of the laboratories reported favorably. T h e degree of general suitability decreased in direct proportion with decreasing concentration of reference material—at less t h a n 1 ppm only 40 % of the replies were favorable. This same trend was observed for organic chemicals as well as metals and alloys. For the analysis of water, however, a t a concentration range of 1000 ppm or less, better t h a n 9 0 % of the reports were favorable. Significantly, unanimous approval was noted for less t h a n 1 ppm. In petroleum, about 6 5 % of the reports were favorable. I n pesticides, however, a t the < 1 p p m level only 2 0 % of the replies were favorable. Availability. Standards for gas chromatography were generally found to be unavailable to the user's satisfaction. F o r example, in water analysis no favorable reports were noted at < 1 p p m b y six laboratories. I n metals and alloys, about 6 5 % reported favora b l y ; in organic chemicals about 5 0 % ; inorganic chemicals about 45 % ; petroleum about 25 % . In contrast, 6 0 % of the laboratories dealing with pesticide analyses reported favorable availability for < 1 ppm standards. Accuracy. T h e accuracy of standards for gas chromatography was found to be quite good. A dissent, however, was noted with re-
