Environmental Chernistrv
An Easily Constructed Aerosol Sprayer The increasing popularity of thin-layer and paper chromatography and related techniques (such as thin-layer electrophoresis) has brought on a demand for easy methods for visuslization of chromatographic sample spots. Commercially available aerosol spray cans me used to provide the pressure necessary to atomize 8. visualization reagent, but these have some disadvantages such as expense, bulky size, need for refills, and generally the need for reagent bottles with 50-100 ml capacity. The figure shows 8, very simple device for producing aerosol sprays of chemical solutions. The spray can he generated simply by blowing into the attached rubber or plastic tube. The reagent solution is held in a 3-in. test tube. Changing test tubes can be easily accomplished by means of the spring clip clothespin. Except for a small hlock of wood (or plastic) and a spring-type clothespin, all of the components are readily available in a. typical laboratory and can he assembled by students. The components are 1hlock of wood (approximately 1in. X 1 in. X 3 in.) 1 medicine dropper, glass 1 melting point capillary tube (break off I/. in. from closed-end type) Aerosol sprayer. Shown with1 piece of ' / I in. flexible tubing about 16 in. in length out tope or rubber bonds nec1 spring clothespin ersary to hold the components 3-in. test tubes (1 X 75 mm) together. tape or rubber bands The manner of construction of the sprayer is obvious except for two critical areas. I n order to get an efficient aspiration (Bernoulli effect) of the liquid up the capillary tube, the top of the capillary should intersect the center of the opening in the medicine dropper tube. To allow for the lip of the test tube to fit between the hlock and clothespin, the clothespin should not be hound too tightly t o the block. I t is suggested that the capillary, eye dropper tube and clothespin he attached individually to the block rather than attempting to attach them all a t once by wrapping the total assembly. Since the capillary will occasiondly get broken and have to he replaced, it should be placed onto the block last so as to allow easy removal of rubber bands or tape. The plastic electrician's tape works best for holding together the components since it is flexible, water repellent and not as likely to slip out of position as would rubber hands.
ROBERTA. PATSIGA INDIANA UNIVERSITY OP PENNSYLVANIA INDIANA, PENNSYLVANIA 15701
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Journol of Chemical Educofion
