10 MICRO-ANALYTICAL METHODS 



5. Beaker Sand Test. Pour a definite amount of the powdered 

 spice or vegetable drug into a beaker, add water, stir until the 

 sand is washed away from the vegetable particles and settles to 

 the bottom of the beaker. Let a stream of water run into beaker 

 so as to wash out the vegetable matter. The final washing and 

 decanting must be done carefully so as not to lose the sand. Salt 

 brine may be used instead of water, should the vegetable matter 

 have a comparatively high specific gravity. Dry the sand and 

 weigh to obtain the percentage of sand present. 



6. Ash Determination. According to the regulation method. 

 The percentage of the acid-insoluble residue should also be de- 

 termined. It should be borne in mind that the ash determination 

 gives only approximate results as far as the presence of clay and 

 dirt is concerned, since the organic matter of dirt is combustible. 

 The ash percentage varies greatly in vegetable drugs, especially 

 in herbs and leaves. The sand percentage is comparatively high 

 in those herbs and leaves having abundant trichomes, especially 

 if the drug plants (or herbaceous spices) bearing such trichomes are 

 grown in dry sandy soil. Dirt (and sand) percentage is apt to 

 be high in roots and rhizomes, particularly when rootlets are 

 abundant and when the gathering, garbling and cleaning is 

 carelessly done. 



There are a number of chemical tests giving color reactions 

 which can be done conveniently by the micro-analyst, as the boric 

 acid reaction with curcuma, the H 2 S04 color reaction with some 

 barks, capsicum, guaiac, resin, cubeb, etc.; the H 2 S04 plus for- 

 maldehyde color reaction with morphine; the ferric chloride 

 color reaction with salicylic acid, etc. These tests should be 

 used when, in the judgment of the analyst, they may serve to 

 give better information regarding the identity, purity and quality 

 of the drug. 



