REPORT FOR A N A L Y T I C A L CHEMISTS
MASS SPECTROMETRY
General Suitability. Replies concerning mass spectrometry were concentrated for the most part on analysis of inorganic and organic chemicals and metals and alloys. Although no appreciable difference in suitability was noted between these three categories, a somewhat lower acceptance rate for organic chemicals being observed, about 75% of the replies were generally suitable. Availability. About 8 5 % of the replies were favorable in organic chemicals analysis, about 60% in inorganic chemicals analysis. In metals and alloys, however, particularly in the concentration range of 1—10 ppm, acceptance was considerably less. Only 4 3 % reported favorably in this category. Accuracy. Standards at higher concentration of inorganic chemicals than 0.1% are satisfactory; however, the accuracy of standards was acceptable to only two thirds of the reporting laboratories. In organic chemicals analysis, approximately two thirds of the replies were favorable with the same order of favorability for metals and alloys. Cost. Replies for all three categories, organic and inorganic chemicals and metals and alloys, were approximately the same—about 80% favorable. Summary. By far, the majority of the replies for this technique was confined to metals and alloys, inorganic chemicals, and organic chemicals. Although the replies were in general somewhat more favorable than might be expected, since widespread application of mass spectrometry in analysis is relatively recent, there is an obvious need to improve both the accuracy and availability of standards. A larger percentage of unfavorable replies was obvious with respect to availability rather than cost of standards. NUCLEAR MAGNETIC RESONANCE SPECTROMETRY
General Suitability. Replies concerning this technique were confined almost completely to inor-
ganic and organic chemicals. In both these areas, the general order of suitability exceeded 80%. Availability. Replies were quite favorable, in excess of 8 5 % , with respect to organic chemicals; a somewhat lower percentage for inorganic chemicals. Accuracy. No cases of dissatisfaction were presented with respect to accuracy of standards of this technique. Cost. All replies concerning cost were favorable. Summary. Although the replies received were limited almost entirely to organic chemicals and, to a lesser extent, inorganic chemicals, the status of standards for nuclear magnetic resonance spectrometry apparently suffers only from a lack of availability. Even with this consideration, a substantial percentage of the laboratories replying appears to be satisfied.
Thin-layer gel filtration with
Sephadex SUPERFINE The advantages of both Sephadex gel filtration andthin-layerchromatography can now be utilized with the Sephadex Superfine. Sephadex Superfine is an important complement to other analytic methods, particularly where only sample quantities of experimental material are available. It is useful also (1) for determining the optimum conditions for column experiments (2) in place of normal Sephadex in gel filtration columns when very high resolution is required (3) as a supporting medium in column electrophoresis and in partition chromatography. Thyroglobulin
OPTICAL EMISSION SPECTROSCOPY
General Suitability. Standards for optical emission spectroscopy in water analysis were unanimously found to be suitable. Standards for petroleum analysis were in general quite suitable except for the 1—10 ppm range. In metals and alloys analysis where the technique finds the greatest usage acceptance, there was considerably less approval. About 65% reported favorably in inorganic chemicals analysis, another area of wide usage. The acceptance was notably higher, particularly for the 10 ppm or less concentration range. Standards for organic chemicals analysis were received with roughly 80% of the replies being favorable. Availability. A marked degree of dissatisfaction is evident as to availability of standards for metals and alloys analysis. The percentage of acceptance is somewhat greater than 50% for 10 ppm and higher. In water analysis for 10 ppm or less, about 70% of the replies were unfavorable. At the less than 1 ppm level, 80% of the laboratories reported unfavorably. The same general statements apply to inorganic chemicals with a somewhat higher order of acceptance. Accuracy. A generally high order of favorable replies to ac-
Molecular weight
Correlation between the molecular weight of 9 proteins and their migration rate in thin-layer gel filtration on Sephadex Superfine G-100 was investigated. Measurements from separate experiments were correlated by expression on the common basis of 6 cm. migration by cytochrome c. (Andrews, P., Biochem- I (1964) 9Î.222, by permission of the author.)
Sephadex Superfine gels can be applied to glass plates with ordinary TLC equipment. They adhere easily to the plates. Addition of a binder is not necessary. Six types of Sephadex from G-25 to G-200 are available in the SUPERFINE grade. The small particle size of Sephadex Superfine (between 10 and 40 microns) permits preparation of thin layers, even with the more porous gels The various Sephadex types have the following fractionation ranges. Approximate fractionation range Polysaccharides Proteins
Type Sephadex Sephadex Sephadex Sephadex Sephadex Sephadex
G-25 G-50 G-75 G-100 G-150 G-200
1 0 0 - 5,000 5 0 0 - 10.000 1.000-50,000 1.000-100.000 1.000-150,000 1,000-200,000
3,000-70,000 4,000-150,000 5,000-400,000 5,000-800,000
For additional technical information on Sephadex Superfine, including booklet Thin-Layer Gel Filtration, write to:
PHARMACIA FINE CHEMICALS INC.
Ph
800 Centennial Avenue, Piscataway. Ν J. 08854 Pharmacia (Canada) Ltd.. 110 Place Crémazie Suite 412. Montreal 11, Ρ Q
(Inquiries outside U. S.A. and Canada should be directed to PHARMACIA FINE CHEMICALS, Uppsala. Sweden.) See ACS Laboratory Guide for All Products/Sales Office Circle No. 161 on Readers' Service Card
VOL. 40, NO. 3, MARCH 1968 • 3 3 A
