The determination of sodium and potassium in blood serum and urine by means of the flame photometer

Abetraets rapidity with which the analysis can be carried out. this permitting, for example, the tracing of losses of sodium and calcium in the sewage effluents. (From the K. V.P. Comp., Ltd., Eqnznoka, Ontario.) R. 0. Scorn WILLEBRANDS, A. F., Jr.; The determination of sodium and potassium in blood serum and urine by means of the flame photometer. Rec. Trav. Chim. Pays-Baa 1950 69 799-821 The flame photometer ueed for the determination of sodium and potassium is a modification of that described by S. D. Boom (Disa.. Amsterdam 1945). The flame utilizes butane at 20 cm water pressure, with a stainleas steel gas jet 0.5 mm in diameter. The burner tube is of Pyrex, with a platinum burner tip consisting of two concentric platinum cylinders 9 and 7 mm in diameter. Air is supplied via an atomizer to a side tube of the Pyrex burner tube. The atomizer is of the injector type and similar to that of BOON. Air at 70 cm mercury pressure is fed vertically into a glass expansion chamber thmugh 8 jet with an internal diamet.er of 0.6 to 0.i mm. The liquid is sucked by the air jet horizontally through a capillary with .a jet diameter of 0.2 to 0.3 mm. The amount of liquid used is about 10 ml per min. but only about 5% of this is fed to the flame, the remainder settling in the expansion chamber. A brass chimney surrounding the flame has two side tubes at the flame height containing lens systems for focussing images of the tlame on the photo-cells. For sodium, the light from the 5890/a doublet ia liltared by means of 8 1.5 cm thick layer of copper sulphate soolution (57 g per litre), and t.hen falls onto a selenium barrier layer photocell, the out,put of which is read on a galvanometer. For potassium, light from the 7665/99 doublet is filtered by a Scmn-r RG.2 red filter. and then falls onto a gas filled caeaium cell. The output of this is amplif%ed by a D.C. amplifier and read on a galvanometer.--Urine samples for the determina tion of sodium and potassium are prepared by filtration and 1 to 100 dilution with water, and are then sprayed directly into the flame. Serum or plasma samples for the determination of sodium are prepared by 1 to 100 dilution of the fresh sample with water and using this solution For the determination of potaesium in serum immediately to prevent coagulation of the proteins. or plasma it was found that dilution of the serum 1 to 25 with water gave equaily ae good results as deproteinizing the sample with trichloracetic acid or colloidal dialyzed iron hydroxide, or by wet acid ignition of the serum. Possible ermrs in the method are considerd. Dithering viscosities, for example, between the diluted sam@~ and the standard solutions were found to have little effect. The determination of sodium is not*influenced by the normal amounts of K, Ca and Mg present in serums, but in urine slight ermrs may occur if more than 200 m eq of K per litre is present. Xo interference is. encountered from ,uk, Ca and Mg in the determination of potassium. (From the U’ilhelmina Hoqdal, Anutedam.) R. 0. SCOTT Drcn. J. and PCGSLEY, L. I.; The arsedc, lead, tin. copper and ‘iron content of canned clams, oysters, crabs, lobsters and shrimps. Canad. J. Res. 1950 28 (Section F) 199-201 The lead, tin, copper and iron contents of the samples were determined spectrographically by a modification of CHOLAK and STORY’S method (Ind. Eng. Chem. (Anal. Ed.) 1938 10 619) usmg bismuth aa the internal standard. (From the Focd & Drugs Lab., Dept. Sat. Health Weffare, Ottawa. R. 0. Scorr Cot)odo.)

Apparatus J. Sci. Instrum. SOMMER, A. and TURK, W. E.; New multiplier phototubes of high sensitivity. 1950 27 113-117 The development of a new type of multiplier phototube, originally designed for television purposes, The tube combines high cathode-sensitivity and high multiplication factor with low is described. noise/signal ratio. RUPERT, C. S. and STRONG,J.; The carbon arc as an infra-red source. J. opt. Sot. Amer. 1950 40 455-459 The crater radiation of a low intensity carbon arc is examined for use as an infra-red source. The performance of the arc as an infra-red source is compared with a Globar operated at 1175” and 1400° K. Details of the arc mounting and operation are given. The arc source is recommended for high re.solution spectroscopy and other applications where a high source intensity is desirable. E. A. BO~NER WHLTE. J. P.; Simple variable space infra-red absorption cell. Fkv. Sci. Instrum. 1950 21 629-ti30 A variable space liquid absorption ccl1 is described for use in the infra-red spectral region. It emplo_ys a close fitting cylinder and piston to keep the windows parallel to each other and minimize leakage. A differential thread and double nut are used to obtain the motion. The sample thickness can be varied from 5 mm to less than 10 p. The minimum volume is about 1 cm3. The windows of rocksalt can be E. -1. BOE~TNER removed for polishing.