rX. SACCHARINE PRODUCTS. 



1 PREPARATION OF SAMPLE.-TENTATIVE. 



(a) Liquids {molasses, sirups, etc.). — Mix materials of this class thoroughly. 

 If crystals of sugar are present, dissolve them either by heating gently or by weigh- 

 ing the whole mass, then adding water, heating until completely dissolved and 

 after cooling, re-weighing. Calculate all results to the weight of the original 

 substance. 



(b) Semisolids (jellies, jams, etc.). — Weigh 50 grams of the sample into a 250 

 cc. graduated flask. Treat with water, fill to the mark and mix thoroughly. If 

 insoluble material remains, mix uniformly by shaking before taking aliquots for 

 the various determinations. 



(C) Solids (sugar, confectionery, etc.). — Grind and mix thoroughly materials 

 of this class to secure uniform samples. 



Moisture. 



DRYING METHODS. 



2 SUGARS.-OFFICIAL. 



Dry 2-5 grams in a flat dish (nickel, platinum, or aluminium) at the temperature 

 of boiling water for 10 hours; cool in a desiccator and weigh; then dry again for an 

 hour or until there is only a slight change in weight. 



With some sugars, more especially those of large grain, there is danger of occlu- 

 sion and retention of water. The International Commission for Unifying Methods 

 of Sugar Analysis prescribe drying at 105°-110°C. for normal beet sugars. This 

 temperature is sufficient to expel the last traces of occluded water and is not attended 

 with sufficient decomposition to affect the weight of the product. The drying tem- 

 perature should never exceed 110°C^ 



MASSECUITES, MOLASSES, AND OTHER LIQUID AND SEMILIQUID PRODUCTS. 



3 Drying upon Pumice Stone.— Tentative. 



Prepare pumice stone of two grades of fineness, one of which will pass through 

 a 1 mm. sieve, the other through a 6 mm. sieve. Make the determination in flat 

 metallic dishes or in shallow, flat-bottomed, weighing bottles. Place a layer of 

 the fine pumice stone, 3 mm. in thickness, on the bottom of the dish, then a layer 

 of the coarse pumice stone 6-10 mm. in thickness, dry and weigh. Dilute the sam- 

 ple with a weighed portion of water so that the diluted material shall contain 20- 

 30% of solid matter. Weigh into the dish, prepared as described above, an amount 

 of the diluted sample to yield, approximately, 1 gram of dry matter. If this weigh- 

 ing can not be made rapidly, use a weighing bottle provided with a cork through 

 which a pipette passes. Dry in vacuo at 70°C. to constant weight, making trial 

 weighings at intervals of 2 hours. For substances containing little or no levulose 

 or other readily decomposable substance, the drying may be made in a water oven 

 at the temperature of boiling water. 



4 Drying upon Quartz Sand.— Tentative. 



Digest pure quartz sand with strong hydrochloric acid, wash, dry, and ignite. 

 Preserve in a stoppered bottle. 



121 



