SACCHARINE PRODUCTS. 49 



For confectionery, as might be expected, from the wide variation in the character 

 and consistency of candies, there is little uniformity in the grade of commercial 

 glucose employed, so that it is not possible as in the case of molasses and honey to 

 calculate the amount present, Nor is it so essential, in view of the fact that commer- 

 cial glucose is rarely regarded as an adulterant of confectionery. 



13. DETERMINATION OF REDUCING SUGARS (ESTIMATED AS DEXTROSE). 



Treat 5 grams of molasses, sirup, or honey, or 25 cc of the 20 per cent solution or 

 mixture (2 (c) (1) (6)) or 5 grams of the powdered confectionery, with water in a 

 100-cc graduated flask, using 2 to 5 cc, of lead subacetate solution in the case of 

 molasses or sirup, and 5 cc of alumina cream in the case of honey or confectionery. 

 Make up to 100 cc, filter, take an aliquot part of the filtrate (25 to 50 cc), and make 

 this up to 100 cc, the amount taken being such that when diluted the solution will 

 contain not more than one per cent of dextrose. If lead subacetate has been used to 

 clarify, add to the aliquot part taken, and before dilution, enough sodium sulphate 

 to precipitate the excess of lead, then filter, and make up to the 100-cc mark. 



Add 30 cc of Fehling's copper solution a to 30 cc of Fehling's alkaline tartarate solu- 

 tion 11 in a 250-cc Erlenmeyer flask. c Add 25 cc of the sugar solution (which must 

 not contain more than 1 per cent of reducing sugar) with a burette, heat to boiling 

 and boil exactly 2 minutes. Separate the precipitate as quickly as possible by filter- 

 ing, with the aid of vacuum, through a layer of asbestos about 1 cm thick in a Gooch 

 crucible (which with the asbestos has previously been ignited, cooled, and weighed), 

 washing the cuprous oxide precipitate with boiling distilled water till the wash water 

 ceases to be alkaline. 



To prepare the asbestos, first boil it with nitric acid (sp. gr. 1.05 to 1.10), washing 

 out the acid with hot water, then boil with a 25 per cent solution of sodium hydroxid 

 and finally wash out the alkali with hot water. Keep the asbestos in water in a 

 wide-mouthed flask or bottle, and transfer it to the Gooch by shaking it up in the 

 water and pouring it quickly into the crucible while under suction. 



Dry the Gooch with its contents in the oven, and finally heat it at dull redness 

 for fifteen minutes. Transfer to the desiccator, cool, and weigh quickly as cupric 

 oxid. A platinum Gooch may safely be used. If a porcelain (Jooch is employed, 

 extra precautions are necessary in heating to avoid cracking. With porcelain use a 

 muffle. 



Or, wash with alcohol and ether, dry for 20 minutes at 100 C. and weigh as cuprous 

 ox id. In either case ascertain the weight of reducing sugar, in terms of dextrose, 

 from Table VIII. 



Or, the copper may be determined from the cuprous oxid in accordance with the 

 official methods. d 



14. DETERMINATION OF ALCOHOL IN SIRUPS USED IN CONFECTIONERY ("BRANDY 



DROPS"). 6 



Open each drop by cutting off a section with a sharp knife and collect in a beaker 

 the sirup of from 15 to 25 of the drops, which will usually yield from 30 to 50 grains of 

 sirup. Strain the sirup into a tared beaker through a perforated porcelain filter 



34.639 grams CuSo 4 5H 2 O, dissolved in water and diluted to 500 cc. 



M73 grams of Rochelle salts and 125 grams of potassium hydroxid dissolved in water and diluted 

 to 500 cc. 



- Dcfren, Jour. Am. Chem. Soc.,1896, 18, 749. 



< U. 8. Dept. of Agr., Div. of Chcm., Bui. 46, p. 37. 



Thirty-second An. Rep. Mass. Board of Health, 1900, p. 757. Reprint, p. 41. 



16648 No. 6502 4 



