Milligrams Milligrams
Milligrams maltose maltose
copper anhydrid hydrate
obtained. oxidized. oxidized.
435 263.7 277.6
430 259.3 273.0
425 255.0 268.4
420 250.9 264.1
415 247.0 260.0
410 243.2 256.0
405 339.4 252.0
400 235.6 248.0
395 231.9 244.1
390 228.2 240.2
385 224.6 236.4
380 221.1 232.7
375 217.7 229.1
370 214.4 225.6
365 211.1 222.2
360 207.9 218.8
355 204.7 215.4
350 201.5 212.1
345 198.3 208.7
340 195.2 205.4
335 192.0 202.1
330 188.8 198.8
325 185.7 195.4
320 182.5 192.1
315 179.4 188.8
310 176.3 185.6
305 173.3 182.4
300 170.3 179.2
295 167.3 176.1
290 164.4 173.0
285 161.4 169.9
280 158.5 166.8
275 155.5 163.7
270 152.6 160.7
265 149.7 157.6
260 146.8 154.6
255 143.9 151.5
250 141.1 148.5
245 138.2 145.5
240 135.4 142.5
235 132.5 139.5
230 129.7 136.5
225 126.8 133.5
220 124.0 130.6
215 121.2 127.6
210 118.4 124.7
205 115.7 121.8
200 112.9 118.9
195 110.2 116.0
190 107.4 113.1
185 104.7 110.2
180 101.9 107.3
175 99.2 104.4
170 96.4 101.5
165 93.7 98.6
160 90.9 95.7
155 88.2 92.8
150 85.4 89.9
145 82.6 87.0
140 79.9 84.1
135 77.1 81.2
130 74.4 78.3
125 71.6 75.4
120 68.9 72.5
115 66.1 69.6
110 63.4 66.7
105 60.6 63.8
100 57.9 60.9
95 55.1 58.0
90 52.3 55.1
85 49.6 52.2
80 46.8 59.3
75 44.1 56.4
70 41.4 53.5
=235. Weighing the Copper as Oxid.=—In the usual methods of the
determination of reducing bodies, the percentage is calculated either
volumetrically from the quantity of the sugar solution required to
decolorize a given volume of the alkaline copper solution, or the
reduced copper suboxid is brought into a metallic state by heating in
an atmosphere of hydrogen or by electrolytic deposition. A quicker
method of procedure is found in completing the oxidation of the cupric
oxid by heating to low redness in a current of air.[192] For this
determination the precipitation of the cuprous oxid and its filtration
are made in the usual manner. The cuprous oxid is collected in a
filtering tube, made by drawing out to proper dimensions a piece of
combustion tube, and has a length of about twelve centimeters in all.
The unchanged part of the tube is about eight centimeters in length
and twelve millimeters in diameter. It is filled by first putting in
a plug of glass wool and covering this with an asbestos felt on top
of which another plug of glass wool is placed. After the cuprous oxid
is collected in the tube it is washed with boiling water, alcohol and
ether. The rubber tube connecting it with the suction is of sufficient
length to permit the tube being taken in one hand and brought into
a horizontal position over a bunsen. The tube is gradually heated,
rotating it meanwhile, until any residual moisture, alcohol or ether,
is driven off from the filtering material. The layer of glass wool
holding the cuprous oxid is gradually brought into the flame and as
the oxidation begins the material will be seen to glow. The heating is
continued for some time after the glowing has ceased, in all for three
or four minutes, the tube and the copper oxid which it contains being
brought to a low redness. The current of air passing over the red-hot
material in this time oxidizes it completely. The filtering tube,
before use, must be ignited and weighed in exactly the same manner as
described above. The heat is so applied as not to endanger the rubber
tube attached to one end of the filtering tube nor to burn the fingers
of the operator as he turns the tube during the heating. After complete
oxidation the tube is cooled in a desiccator and weighed, the increase
of weight giving the copper oxid. For the atomic weights, 63.3 copper
and 15.96 oxygen, one gram of copper oxid is equivalent to 0.79864
gram of copper, and for the weights 63.17 copper and 15.96 oxygen, one
gram of copper oxid equals 0.79831 gram of copper. From the amount of
metallic copper calculated by one of these factors, the reducing sugar
is determined by the tables already given.
=236. Estimation of Dry Substance, Polarization and Apparent Purity for
Factory Control.=—For technical purposes the methods of determining
the above factors, proposed by Weisberg and applicable to concentrated
sirups, massecuites, and molasses, may be used.[193] Five times the half
normal quantity of the material, _viz._, 65.12 grams, are placed in a
quarter liter flask, dissolved in water and the flask filled to the
mark. In the well shaken mixture, which is allowed to stand long enough
to be free of air, the degree brix is estimated by an accurate spindle.
For example, in the case of molasses, let the number obtained be 18.8.
Fifty cubic centimeters of the solution are poured into a 100 cubic
centimeter flask, the proper quantity of lead subacetate added, the
flask filled to the mark with water, its contents filtered, and the
filtrate polarized in a 200 millimeter tube. Let the number obtained
on polarization be 22°.1. This number may be used in two ways. If
it be multiplied by two the polarization of the original sample is
obtained; in this case, _viz._, 44°.2. In the second place, if 44.2 be
multiplied by 0.26048 and this product divided by the specific gravity
corresponding to 18°.8. _viz._, 1.078, the quotient 10.68 is secured
representing the polarization or per cent of sugar contained in the
solution of which the degree brix was 18.8°. From the numbers 18.8 and
10.68 the apparent purity of the solution, 56.8, is calculated, _viz._,
10.68 × 100 ÷ by 18.8. The original product as calculated above gives a
polarization of 44.2 and this number multiplied by 100 and divided by
56.8 gives 77.8, or the apparent percentage of dry matter. The original
sample of molasses, therefore, had the following composition:
Degree brix (total solids) 77.8 per cent.
Sucrose 44.2 ”
Solids, not sucrose 33.6 ”
Apparent purity 56.8 ”
It is seen from the above that with a single weighing and a single
polarization, and within from ten to fifteen minutes, all needful
data in respect of the proper treatment of molasses for the practical
control and direction of a factory can be obtained.
In case a laurent polariscope is used, five times the normal weight,
_viz._, eighty-one grams of the raw material are used and the process
conducted as above.
SUCROSE, DEXTROSE, INVERT SUGAR, LEVULOSE, MALTOSE, RAFFINOSE, DEXTRIN
AND LACTOSE IN MIXTURES.
=237. Occurrence.=—Sucrose and invert sugar are found together in many
commercial products, especially in raw sugars and molasses made from
sugar cane, and in these products sucrose is usually predominant. They
also form the principal saccharine contents of honey, the invert sugar,
in this case, being the chief ingredient.
In commercial grape sugar, made from starch, dextrose is the important
constituent, while in the hydrolysis of starch by a diastatic ferment,
maltose is principally produced. In the manufacture of commercial
glucose by the saccharification of starch with sulfuric acid, dextrin,
maltose, and dextrose are the dominant products, while in the similar
substance midzu ame, maltose and dextrose are chiefly found, and only a
small quantity of dextrose.[194] In honeys derived from the exudations
of coniferous trees are found also polarizing bodies not enumerated
above and presumably of a pentose character.[195] In evaporated milks
are usually found large quantities of sucrose in addition to the
natural sugar therein contained. These mixtures of carbohydrates often
present problems of great difficulty to the analyst, and the following
paragraphs will be devoted to an elucidation of the best approved
methods of solving them.