Edward W. Bermes

Some fundamental aspects of centrifugally accelerated paper chromatography

Abstract A study has been made of some of the fundamental factors involved in obtaining good separations and reproducible chromatograms, with the technique of contrifugally accelerated paper chromatography. A study was also made of variables which might influence R F values. Mixtures of bromphenol blue, methyl orange and methyl red were fractionated as well as solutions of lencine, methionine and glycine. For the separation of the dyes, Whatman No. 1 filter paper was used with a veronal buffer solution of ionic strength 0.05 and having a pH of 8.7. For this system, it was found that the R F values of the dyes were essentially unaffected by changes in rotational speed of the rotor from 300 to 925 r.p.m. It was found that the rate of addition of solvent was important in developing satisfactory chromatograms. A flow rate of 1.15 ml/min was found to be satisfactory at all rotational speeds above 250 r.p.m. The shape of the developed chromatogram was elliptical rather than circular, for all four types of paper which were studied. For Whatman No.1, the major axis of the ellipse was parallel to the machine direction of the paper. The R F values for the dye components were essentially the same for the following papers: Whatman No. 1, Eaton-Dikeman No. 613, and Cremer-Tiselius-Munktells. The amino-acid mixture was fractionated using Whatman-3MM paper and a solvent system of butanol-glacial acetic acid and water, in the volume ratio 40:10:10, respectively. The disk was rotated at 975 r.p.m. With a solvent flow rate of 1.2 to 2.1 ml/min, sharply defined zones were obtained. The time of development was 15 min for a flow rate of 1.2 ml/min and 7 min for a flow rate of 2.1 ml/min. The R F values obtained were 0.85 for lencine, 0.56 for methionine and 0.20 for glycine.

Paper chromatography in a centrifugal field

I n Fig. 1 s ieh t m a n Muster , die t ro tz sorgfSldger Glfihb e h a n d l u n g der P robe u m eine Vert iefuf lg e n t s t a n d e n sind. Es h a n d e l t s ich u m keimffSrmige Gebilde, die sich, d e m Weehse l der S p a n n n n g s r i c h t u n g folgend, k re i s f6rmig u m die ra t ion of at l eas t four ions in a m i x t u r e w h e n t he vo l t age is m a i n t a i n e d a t t50 V a n d t he c u r r e n t is passed for 5 hours . One drop (0.0t ml.) of a q u a r t e r n a r y m i x t u r e of so lu t ions of t h e ions of Pd ( I I ) , P t ( IV) , I r ( IV), R h ( I I I ) , R u ( I I I ) , Os(IV) a n d Au (III) con t a in ing on ly m i c r o g r a m a m o u n t s of each ion is suf f ic ient for s a t i s f ac to ry separa t ion . Sequences of s epa ra t i ons are in t h e order g iven below.

Evaluation of a direct agglutination latex particle test for human chorionic gonadotropin

The direct agglutination particle slide test for human chorionic gonadotropin (HCG) was evaluated on 147 urine and 92 serum specimens. The test involves latex particles coated with HCG antibody as the only reagent and agglutination is read as positive, within 2 minutes. 98% of the urine specimens were read correctly, with only 2 false positives and 2 false negatives. Serum is diluted 1:1 with the saline supplied: this gave only 1 false positive. Experiment with added HCG showed that the sensitivity was 2 IU HCG. Added protein up to 1.6% in urine did not interfere with the results. The panel discussion mentioned the problems of low HCG in early pregnancy, and of posible prozone phenomena in case of high HCG as may occur in hydatidiform mole or in later pregnancy.

Effect of temperature on ionographic mobilities in paper stabilized media.

Summary The effect of temperature on velocity of electromigration through paper stabilized electrolytes, of a variety of substances, including bromphenol blue, bovine plasma albumin, human serum albumin and globulin fractions and human serum lipoproteins, was investigated. The ionographic apparatus employed utilized horizontal paper strips in a water saturated atmosphere. The runs were made at temperatures from 4°C to 25°C and under constant conditions of buffer, ionic strength, pH and potential gradient. For all substances studied, the relationship between the mobility and temperature can be represented by the equation: where T is ° Kelvin, B is a constant and m is the slope of the line obtained when the logarithm of the mobility is plotted against the reciprocal of the absolute temperature.