A Simple, Inexpensive Zone Extractor for Preparative Thick-Layer Chromatography The general method of removing zones of absorbent from preparative t,hinlayer chromatography (tlc) plates by scraping with spatulas, razor blades, etc., is , , , , , , tedious and leads to unavoidable contamination wibh neighboring zones. A tlc B., A N D HIRSCH,J., J. Lipid Research, 4, 482 (1063)l eone extractor [G~LDRICK, constructed from a disposable pipet plugged by glass wool a t one end has been found 8-1 ren, ineffective for large scale preparative thin-layer a?well as thick-layer chromatography 10 -ml .IPi,.b M. W., J. CHEM.EDUC.,44, Another zone extractor [RUCHELMAN, separations. b h h l mina. nsimnn> 110 (1967)l consisting of a piece of glass tubing with a sintered glass disc in the expanded center portion necessitates glass blowing for its canstmct,ion. An even , greater disadvantage of the latter is that unless a. critical pore size of the sintered glass disc is ued, any deviation will result in poor suction or inadequate retention of the absorbent. Commercial zone extractors are too costly, especially when considering their use in large undergraduate laboratories. In this communication we wish to report a. simple eone extractor for large scale thin-layer and thick-layer chromatography which e m be readily constructed from common la.horatory equipment (see figure). With this apparatus, i t has been found that 10-12 g of silica gel can be sucked into the disposable Soxhlet thimble, B. The silica eel mav he transferred to another container for extraction numoses . with as little as 25 me loss of material. This ouantitat,ive recoverv of d i e s sel allows t,he thimhle t,o he used reoeat,edlv for removal of other zones from
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t o 300 mg consisting of more than three different compounds can be separated on one thick-layer plate (20 X 20 X 0.5 cm) free from mechmicd contamination
Volume 46, Number 1 1 , November 1969
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