A simple procedure for removing salts from samples applied to ion-exchange thin-layer plates
✍ Scribed by John M. Foster; Hilary Abbott; Mary L. Terry
- Publisher
- Elsevier Science
- Year
- 1966
- Tongue
- English
- Weight
- 269 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0003-2697
No coin nor oath required. For personal study only.
✦ Synopsis
Recently Randerath described several simple systems for separating millimicromolar quantities of nucleotides by thin-layer chromatography on ion-exchange celluloses (1, 2). The sensitivity of these methods obviously depends upon the volume of sample which can be chromatographed. For many biological systems this volume is limited to that which can be applied to a thin-layer plate before the salts in the sample begin to interfere. If larger volumes of sample must be chromatographed, the use of tedious and often impracticable desalting procedures then becomes necessary. In ion-exchange column chromatography, on the other hand, interference by salts is often avoided by diIuting the sample to lower the salt concentration. The substances to be separated then concentrate in a narrow band at t,he t,op of the column as the diluted sample is run through. It occurred to us that t'he same technique might be applicable to an ion exchanger on a thin-layer plate, provided some means could be devised for running a considerable volume of liquid very slowly onto the origin of t.he plate. We wish to report a method that has proved convenient for isolating 10 mpmoles or less of adenine nucleotides from as much as 0.5 ml of incubation medium without pretreatment to remove salts.
Details of the apparatus arc shown in Fig. lil. Each sample is chromatographed on a separate 2"' X 8"' pIate coated with an appropriate ion exchanger. Two strips of Whatman No. 31 filter paper, 2" wide and approximately IO" long, are each folded two or three times at one end to form a small pad. The pads are sandwiched between the thin-layer plate and a Plexiglas plate, which has a l/sxi)' hole 11/g" from one end. The sandwich is fastened t.ogcther with rubber bands and placed on a level rack so that the filter paper strips hang free over the edges. Up to 0.5 ml of Porn-'Supported in part by USPHS Grant No. CA-05098 and hy AEC Contract ?\To. AT (30-l) 1845. 149