Inexpensive Chromatography Sprayer for the Chemistry Lab The use of chromatography sprayers is a vital technique for paper and thin- layer chromatography (TLC), and it also has a place in electrophoresis, henzidine tests for blood, etc. Unfortunately, the high cost of commercial chromatography sprayers limits their use, leading us to cheaper alternative atomizers. A simple hair spray bottle can he used as a chromatography sprayer, hut the disadvantages ofthis type of atomizer are that they do not have a fine uniform spray required for the development ofchromatographic patterns as well as the possibility of a n undesirable reaction with the plastic bottle-r the plasticizers in it--due to a strong locating agent. A goad alternative that we have been using for several years in our laboratory and in the undergraduate laboratory is an inexpensive chromatography sprayer constructed from readily available chemistry stockroom materials. It consists of two 17-em pieces of standard-wall Pyrex tubing (4 mm a d . ) constricted in one end by a Bunsen burner to a 0.8 mrn bare (resembling a pipet tip); two rubber stoppers (no. 5 and no. 8, the farmer having a vertical notch to allow air entrance); a 125-mL Erlenmeyer flask; 1 rn of rubber tubing ( 5 mm. i.d.); and a source of air, such as a plain rubber bulb of 1%-oz. capacity or an air rlenmeyer pump. The apparatus is assembled as shown in the figure and gives very reliable results. Tube Ais bent 90" a t approximately 2 cm from the tip with a Bunsen burner; take precautions not to melt the tip. Tubes A and B are fitted in ano. 8 rubber stopper; takenoteofthe detailofthe position ofthe tips, as shown in the diagram, for proper operation. Tube A is bent again and the open end is fitted with the rubber tubing and air source. Tube B is fitted through a no. 5 rubber stopper and placed as shown. The sprayer is tested with water, and the best position for the tips is found; then the tubes are set with silicone rubber sealer a t the base of the no. 8 stopper.
L. A. Lopez-Dellamary Universidad Autonoma de Baja California Sur Lab. de Farmacognosia La Paz, B.C.S., Mexico
432
Journal of Chemical Education
