a. Brix: A quantity of t h e material is dissolved in six times its weight of distilled water a n d the brix determined as in chapter V I I , 3.
T h e reading multiplied by 7 = brix of the original sample.
b. Dry substance: A p p r o x i m a t e l y 4 0 - 5 0 g acid washed a n d ignited
Laboratory Manual for S. A f r . Sugar Factories 1962 — 67
quartz sand (about 40-100 mesh) in an aluminium dish together with a small glass stirring rod are dried in an oven a n d cooled in a desiccator. T h e dish shall have a tightly fitting lid, be 8 cm in diameter, 1.5 cm in height and be m a d e of 24 gauge aluminium. T h e length of the glass stirring rod shall be slightly less t h a n the diameter of the aluminium dish.
A b o u t 20 g molasses are weighed accurately into a tared weighing bottle provided with a stirrer a n d closely fitting lid.
Approximately 80 g water are added, the mixture stirred until h o m o - geneous (a mechanical stirrer is recommended), the lid replaced a n d the weighing bottle a n d contents reweighed.
F r o m this diluted molasses a sample of approximately 10 ml is pipetted into the weighed aluminium dish which is then reweighed.
T h e diluted molasses is mixed intimately with the sand using the glass r o d which, after mixing, is allowed to remain in the dish.
T h e International Commission for Uniform M e t h o d s of Sugar Analysis specifies t h a t the drying be carried out at a temperature n o t exceeding 70°C, preferably 60°C, u n d e r a pressure n o t exceeding 5 cm Hg until successive weighings at two-hourly intervals do n o t differ by m o r e t h a n 0.5 mg. T h e dried sample is cooled in a desiccator before weighing.
Sucrose
i. T H E J A C K S O N & G I L L I S M E T H O D I V : W e i g h o u t
32.5 g of molasses. Dissolve a n d m a k e up to the m a r k with water in a 250 ml flask. Part of this solution is used for the determination of reducing sugars as described in 10, d below.
To the remainder add sufficient dry lead sub-acetate for clari- fication (usually a b o u t 6 g), shake well and allow to stand for a few minutes before filtering. To the filtrate add the m i n i m u m of a n h y d r o u s potassium oxalate necessary for de-leading (usually a b o u t 4 g), shake well and again filter. N o w pipette 50 ml portions into 100 ml flasks a n d proceed with either m e t h o d a or b of chapter VII, 5. T h e readings a r e m a d e in 200 mm tubes. If the solution is very dark, a d d a pinch of zinc dust for decolourizing.
1962 Laboratory Manual for S. A f r . Sugar Factories
T h e actual saccharimeter readings multiplied by 4 in each case will give P D a n d P I . T o convert ( P D — P I ) into S , the modified Clerget F o r m u l a in 5, c, iii (for acid inversion) or 5, d, ii (for invertase inversion) above, should be used, where m is the weight in grams of dry substance in the 50 ml of solution taken for inversion. However, since the accuracy of the sucrose determination in final molasses by the J a c k s o n and Gillis m e t h o d is n o t very great, no significant e r r o r is m a d e if a constant value of 132.0 is t a k e n for the divisor when t is within the limits 19° to 21°C.
W h e n t is either m o r e t h a n 21°C or less t h a n 19°C the value 132.0 shall be corrected for t in the n o r m a l way. T h e above simplification is permitted only if a sample of ordinary final molasses is analysed. In other cases the usual c o n c e n t r a - tion correction shall be calculated a n d applied, a n d if Table Va is used the " C o r r e c t e d brix before d i l u t i o n " is the brix of the half n o r m a l solution of the sample,
ii. T H E C H E M I C A L M E T H O D * , U S I N G I N V E R T A S E : 2 6 g of final molasses are weighed o u t and transferred q u a n t i t a - tively to a 200 ml volumetric flask. After m a k i n g to volume this solution is used for the d e t e r m i n a t i o n of reducing sugars before a n d after inversion as follows:—
a. 20 ml of the filtrate are pipetted into a 200 ml volumetric flask a n d m a d e to volume. This solution is titrated against 10 ml of Fehling's solution for the d e t e r m i n a t i o n of reducing sugars.
b. 50 ml of the filtrate are pipetted into a 100 ml Erlenmeyer flask a n d diluted to approximately 80 ml a n d b r o u g h t to pH 4.7 ± 0.2 by the addition of a pre-determined volume of glacial acetic acid. To this solution is a d d e d the invertase, the a p p r o p r i a t e quantity of which was determined by the m e t h o d given in chapter VII, 5, b, ii. If the concentrate is of n o r m a l activity 2.5 ml are added, otherwise a p r o r a t a volume. T h e flask is placed in a water b a t h at 57-58°C for 15 minutes with occasional shaking. After cooling the solution is transferred quantitatively to a 500 ml volumetric flask a n d m a d e to volume. This solution is titrated against 25 ml of Fehling's solution for the d e t e r m i n a t i o n of reducing sugars after inversion.
T h e a m o u n t of reducing sugars found after inversion gives the percentage of total sugars present. To calculate the sucrose percentage b o t h reducing sugar c o n c e n t r a t i o n s are expressed as a percentage of the original sample. T h e per- centage reducing sugars before inversion is deducted from the
* Especially for dark-coloured molasses, this m e t h o d yields m o r e accurate results than the Jackson & Gillis m e t h o d .
Laboratory Manual for S. Afr. Sugar Factories 1963 — 69
total sugars and the difference multiplied by 0.95. This is necessary to compensate for the fact t h a t 95 parts of sucrose on hydrolysis yield 100 parts of reducing sugars.
d. Reducing sugars: Pipette 20 ml of the diluted solution prepared for the determination of sucrose (10, c above) into a 200 ml volumetric flask and m a k e to the m a r k with distilled water. Titrate this solution, which is a 1.3% solution of original molasses, against Fehling's solution as described in chapter VII, 6, a. F r o m the column for 0.5 g sucrose per 100 ml in Table IV obtain the concentration of reducing sugars per 100 ml and express this concentration as the percentage of reducing sugars in original molasses.
e. Total sugars: As a gauge for the value of final molasses to secondary industries, the percentage of total sugars is often calculated. T h e percentage is found by adding the percentage of reducing sugars and 1.05 x the percentage of sucrose.
f. Sulphated ash: As described in chapter VII, 13. A b o u t 5 g is normally adequate for ashing.
1 1 . S u g a r s a. Pol
i. T h e p r e p a r a t i o n of the solution of the sugar a n d the reading of the saccharimeter should be carried out at or as near as possible to 20°C. T h e time of the day for the analysis of composite samples should be chosen accordingly. If it is n o t possible to w o r k at 20°C the volume of the solution in the 100 ml flask should be completed at the same t e m p e r a t u r e at which the saccharimeter is read and the reading should be corrected for the deviation of the temperature from 20°C.
F o r every degree above 20°C, 0.03°S should be a d d e d to the p o l ; for every degree below 20°C, 0.03°S should be deducted from the pol.
ii. Dissolve the n o r m a l weight of the sugar in distilled water in a 100 ml volumetric flask. Dilute to approximately 80 ml a n d a d d 1.0 ml of lead sub-acetate solution. Mix the solution by swirling and add water until the volume is roughly 96 ml.
T h o r o u g h l y mix a n d then wash d o w n the sides of the flask until the volume is approximately 99.5 ml. Disperse any bubbles which have collected at the surface with one d r o p of diethyl ether. Dry the inside neck of the flask above the solution level with rolled filter paper and m a k e the volume to exactly 100 ml by adding water from a fine d r o p p e r . Mix the solution thoroughly a n d allow to stand for 5 minutes. Filter t h r o u g h an 18.5 cm fluted filter paper contained in a plain stemless funnel, pouring all the contents of the flask into the 70 — 1963 Laboratory Manual for S. A f r . Sugar Factories
paper. Immediately cover the funnel with a cover glass.
Discard the first 10 ml of filtrate a n d collect a further 30 ml of filtrate for polarization in a 200 mm tube at 20°C. It is preferable to use a jacketed tube to prevent w a r m i n g by the h a n d s .
All operations after weighing should be carried out at a t e m p e r a t u r e as near 20°C as possible. T h e funnel should be sufficiently large to prevent the p a p e r projecting above it and during filtration should remain covered with a clock glass.
b. Reducing sugars by the Luff-Schoorl method: Weigh out accurately 20 g of the sample a n d transfer to a 100 ml volumetric flask. Dissolve in distilled water and m a k e up to volume. Shake well. ( N o r m a l l y no clarification of the solution is required.) In the case of refined a n d mill-white sugars, accurately pipette a 25 ml aliquot of the solution into a 500 ml Erlenmeyer flask containing 25 ml of the Luff solution. F o r r a w sugars a 25 ml aliquot is normally satisfactory b u t for r a w sugars containing a high percentage of reducing sugars it may be necessary to decrease the aliquot taken. In such a case the volume must be m a d e up to 25 ml w i t h water, e.g. if a 10 ml aliquot is taken 15 ml water m u s t be a d d e d . To prevent boiling over a d d a few pieces of washed and ignited unglazed porcelain.
Fit an upright condenser to the flask which rests on a c o p p e r gauze over a circular opening with a diameter slightly less t h a n t h a t of the b o t t o m of the flask. H e a t the flask so t h a t the solution boils within 3 minutes a n d continue boiling for exactly 5 minutes longer.
Cool the solution rapidly in running water, taking care t h a t the precipitated c u p r o u s oxide does n o t c o m e into contact with the air. Immediately add 15 ml of potassium iodide solution a n d then slowly, with careful swirling, 25 ml of sulphuric acid solution. As soon as the evolution of c a r b o n dioxide ceases titrate the liberated iodine with the N / 1 0 thiosulphate solution. W h e n the end p o i n t is a p p r o a c h e d add I ml of the starch solution. Carry out a blank determination using 25 ml of distilled water in place of the sugar solution. Refer the difference between the volume of N / 1 0 thio- sulphate solution required by the b l a n k a n d the test, corrected for normality, to Table VI a n d calculate the percentage reducing sugars in the sample.
c. Colour of white sugars
i . S A M P L E P R E P A R A T I O N : H o t distilled water a t a tempera- ture of 90-100°C is a d d e d to the weight of sugar required to p r e p a r e a solution of a c o n c e n t r a t i o n of 50 ± 0 . 2 % refracto- meter solids. T h e sugar-water mixture is stirred gently to bring the sugar into solution. C o o l the solution to a b o u t r o o m t e m p e r a t u r e before m e a s u r e m e n t . N o filtration should be m a d e n o r should the pH be adjusted.
Laboratory Manual for S. A f r . Sugar Factories 1963 — 71
N . B . Stainless steel or glass bottles or beakers should be used to prepare the solution. Aluminium beakers should not be used as they introduce turbidity.
ii. M E A S U R E M E N T : The solution should be measured in a 10 cm cell using a suitable spectrophotometer at wavelengths 420 my. and 720 my.. T h e cell should be located as close to the photocell as possible.
iii. R E F E R E N C E S T A N D A R D : T h e reference s t a n d a r d should be a 50 ± 0 - 2 % solids colourless sucrose solution. F o r practical purposes the reading with a colourless sugar solution may be correlated with a secondary s t a n d a r d such as distilled water or air and a balance point established on the scale which will give the equivalent of a colourless sucrose solution.
d. Sulphur dioxide: F o r raw and refined sugars either the rapid m e t h o d or the Monier-Williams m e t h o d is used—see c h a p t e r VII, 7, b a n d 7, c.
e. Moisture: F o r white sugars and r a w or similar type sugars t a k e 25 a n d 10 g of sample respectively. Accurately weigh the sample of the sugar i n t o a polished a l u m i n i u m dish provided with a tight- fitting cover. T h e dish shall be 8 cm in diameter, 1.1 cm in height a n d m a d e of 24-gauge aluminium sheet. D r y in an oven at 105°C for 3 h o u r s . Replace the cover of the dish, cool in a desiccator a n d weigh.
f. Sulphated ash: See chapter VII, 13.
g. Conductometric ash {for mill white and refined sugars): T h e gravi- metric determination of bisulphated ash on a refined sugar containing less t h a n 0 . 0 3 % ash requires the use of a precision 72 — 1963 Laboratory Manual for S. Afr. Sugar Factories
analytical balance, expensive p l a t i n u m w a r e a n d very careful analytical technique. A m u c h simpler a n d often m o r e reproducible m e t h o d is to measure the electrical c o n d u c t a n c e of a solution of sugar which will t h e n usually bear a direct relationship to the soluble ash in the sugar. Electrical c o n d u c t a n c e is the reciprocal of the electrical resistance a n d in the case of sugar solutions, specific conductivity m a y be defined as the reciprocal of the resistance of a c o l u m n of liquid 1 cm long a n d having a cross-sectional area of 1 cm2. It is usually reported as reciprocal m e g o h m s b u t may be converted to conductivity ash by multiplying by a factor. T h e measurement of the conductivity of white sugar in solution at 20°C is described in chapter VII, 8.
h. Grain size distribution: Refined or mill white sugars m a y be screened as received b u t with r a w sugars it is necessary to remove the film of molasses s u r r o u n d i n g the crystals prior to screening.
This may be achieved using the m e t h o d described in I . C . U . M . S . A . , 10 (1949) 27. Full details of this m e t h o d are given below.
E Q U I P M E N T
i. Erlenmeyer flask, 250 ml capacity, wide m o u t h ( l i in.
diam.), with a N o . 8 solid r u b b e r stopper. A wide- m o u t h bottle o f a b o u t t h e same capacity m a y b e used, ii. A strainer stopper m a d e from the following: N o . 7
r u b b e r stopper, with central hole 3/4 in. to 7/8ths in. d i a m . ; r u b b e r t u b i n g 11/2 in. wide (used with c a r b o n filter);
disc of 100-mesh wire cloth l1/4 in. diam. C u t a b a n d 1 in. wide off r u b b e r tubing. W o r k this over small e n d of r u b b e r stopper leaving a b o u t 3/16ths in. projecting beyond the end. Peel back projecting tubing, place metal cloth disc on small end of stopper a n d hold in place by slipping over it t h e projecting p a r t of r u b b e r tubing,
iii. Filter flask, 500 ml capacity, with side outlet.
R E A G E N T S
i. Absolute m e t h a n o l ,
ii. 9 5 % by vol. m e t h a n o l , p r e p a r e d by diluting 95 ml absolute m e t h a n o l to 100 ml.
iii. 90 % by vol. m e t h a n o l , p r e p a r e d from absolute m e t h a n o l or from 9 5 % m e t h a n o l (100 ml to 5 ml H20 ) . iv. Diethyl ether.
P R O C E D U R E
P u t 100 g r a w sugar in Erlenmeyer flask; a d d 100 ml 9 0 % m e t h a n o l ; stop with solid s t o p p e r ; shake contents to m i x ;
Laboratory Manual for S. Afr. Sugar Factories 1962 — 73
allow to soak for 1 h o u r , shaking every 15 min. a few times to mix. T h e n take flask in one h a n d , with the index finger over stopper a n d t h e flask resting in p a l m of h a n d ; rock flask back a n d forth, causing sugar to be sluiced from one end to the other. Do this for 2 min. m a k i n g 120 cycles per min. Let sugar settle and, with flask inclined, tilt to wash crystals from a r o u n d stopper.
Remove solid s t o p p e r ; replace by strainer-stopper ii, loosely inserted. P o u r off m e t h a n o l t h r o u g h strainer, finally inverting Erlenmeyer flask over filter flask to drain into latter.
Apply suction to drain crystals a n d extract as m u c h m e t h a n o l as possible.
A d d 50 ml 95 % m e t h a n o l , p o u r i n g some t h r o u g h loosened strainer-stopper; then remove stopper a n d p o u r remainder of m e t h a n o l on stopper to wash crystals into flask. Stop with solid stopper and shake for 2 min. as before, etc. Repeat with 50 ml 95 % m e t h a n o l three times, m a k i n g in all four applications of the 95 % m e t h a n o l .
T h e n wash crystals in the same m a n n e r with four 50 ml p o r t i o n s of diethyl ether, shaking for 1 min. instead of 2 min. M o s t of the diethyl ether of the last wash can be extracted by leaving the Erlenmeyer flask on the filter flask u n d e r v a c u u m for several minutes.
Spread the washed crystals on a piece of clean paper to air-dry; the crystals on the sides of the flask need n o t be removed. W h e n nearly dry (i.e. when crystals no longer feel cold a n d begin to cake), r e t u r n the sugar to the flask a n d shake a few times; spread again on p a p e r for a few minutes. R e t u r n sugar to flask a n d shake a few times; crystals should n o w be free running and dry.
S I E V I N G T E S T
F o r mill white and refined sugars five Tyler s t a n d a r d screens (10, 14, 20, 28 and 48 mesh) while for raw sugars four Tyler standard screens (10, 16, 28 and 42 mesh) are used. T h e sample for screening is weighed prior to placing on the t o p sieve a n d sifting is carried out for 10 minutes (the R o - T a p h a n d or m o t o r - o p e r a t e d machine is r e c o m m e n d e d ) , after which the weights of the fractions are ascertained. T h e weights of the fractions are expressed as percentages of the total weight of the sugar sifted.
C A L C U L A T I O N O F S P E C I F I C G R A I N S I Z E
T h e m e t h o d of calculation given below is t h a t described by D o u w e s D e k k e r in S.A.S.T.A. Proceedings, 26 (1952) 46.
T h e m a i n criterion calculated from the results of the sieving test is the specific surface (U) of the material tested.
74 — 1962 Laboratory Manual for S. Afr. Sugar Factories
U is the ratio between the total surface of all particles a n d the total surface of the same weight of particles the diameter of which is 1 cm. T h e particles are supposed to be spheres. U is calculated from Z u n k e r ' s formula,
in which d1 = the diameter of the smallest particle a n d d2 = the diameter of the largest particle.
T h e specific grain size (S.G.S.) is calculated from U by the simple f o r m u l a :
In the following table the values for TJ a n d S.G.S., as c o m p u t e d from the openings of t h e Tyler sieves, are given for the six fractions of a sugar-sieving test. d1 of the sixth fraction is assumed to be 0.15 m m . Since the use of three decimals is n o t necessary a n d suggests a false degree of accuracy t h e values of U a n d S.G.S. which are actually used in the c o m p u t a - tion of a sugar-sieving test are also given.
First fraction Second „ Third „ F o u r t h „ Fifth „ Sixth „
U
4.712 7.235 10.17 14.37 24.47 48.49
S.G.S.
m m
2.122 1.382 0.983 0.695 0.409 0.206
U S.G.S.
F o r practical use in sugar analysis 4.8
10.0 7.2 14.3 25.0 50.0
2.1 1.4 1.0 0.7 0.4 0.2
To calculate the specific grain size of a sugar from the sieve test results, the weight of each fraction (expressed as a percentage of t h e total weight) is multiplied by the corres- p o n d i n g value of U. T h e p r o d u c t s are a d d e d a n d the sum divided by 100. T h e quotient is the specific surface of the sugar tested which, divided into 10 gives the specific grain size in m m .
Example:
First fraction Second „ Third „ F o u r t h „ Fifth „ Sixth „
Sieve test result, % 1 15 55 26 2 1
U 4.8 7.2 10.0 14.3 25.0 50.0
P r o d u c t 4.8 108.0 550.0 371.8 50.0 50.0
Laboratory Manual for S. Afr. Sugar Factories 1962 — 75
76 — 1962 Laboratory Manual for S. Afr. Sugar Factories T h e values of U for the fractions obtained when t h e 10, 16, 28 a n d 42 mesh screens are used are 4.4, 7.9, 13.2, 22.3 and 41.4 respectively.
T A B L E I I
Temperature corrections to readings of brix hydrometers (20°C)
Temperature
I5°C .. . I6°C .. - I7°C .. . I8°C .. . I9°C .. .
2I°C .. . 22°C .. . 23°C .. . 24°C . . . 25°C . . . 26°C .. . 27°C .. . 28°C . . . 29°C . . . 30°C . . . 3I°C .. . 32°C . . . 33°C .. . 34°C . . . 35°C .. .
Hydro- meter No. 0
0.21 0.18 0.14 0.10 0.05
0.05 0.10 0.16 0.22 0.28 0.34 0.40 0.47 0.54 0.61 0.68 0.76 0.84 0.92 1.00
Hydro- meter No. 1 Subtract
0.23 0.18 0.14 0.10 0.05 A d d 0.05 0.11 0.17 0.23 0.29 0.35 0.42 0.49 0.56 0.63 0.70 0.78 0.86 0.94 1.03
Hydro- meter No. 2
Hydro- meter No. 3 From observed percent
0.26 0.21 0.16 0.11 0.05 to observed
0.06 0.12 0.18 0.25 0.32 0.39 0.45 0.52 0.60 0.67 0.75 0.83 0.91 0.99 1 .08
0.29 0.24 0.19 0.13 0.06 percent
0.06 0.13 0.20 0.27 0.33 0.40 0.47 0.55 0.63 0.71 0.79 0.88 0.96 1.04 1.13
Hydro- meter No. 4
0.33 0.27 0.21 0.14 0.07
0.07 0.15 0.22 0.30 0.37 0.44 0.52 0.60 0.68 0.76 0.84 0.93 1.01 1.09 1.18
Hydro- meter No. 5
0.37 0.30 0.22 0.15 0.08
0.08 0.16 0.23 0.31 0.39 0.47 0.55 0.63 0.71 0.80 0.88 0.97 1.05 1.13 1.22
Laboratory Manual for S. Afr. Sugar Factories 78 — 1962
T A B L E I V
Table giving mg invert sugar required to reduce 10 and 25 ml of Fehling's solution in the presence of different amounts of sucrose
ml Sugar Solution Required
15 ..
16 ..
17 ..
18 . . 19 20 21 . . 22 ..
23 24 25 26 27 ..
28 29 ..
30 31 . . 32 . . 33 . . 34 . . 35 . . 36 . . 37 ..
38 ..
39 ..
40 . . 41 ..
42 . . 43 ..
44 ..
45 . . 46 ..
47 . . 48 ..
49 ..
50 ..
Og 336 316 298 282 267 255 243 232 222 213
! 205 197 190 184 178 172 166 161 157 152 148 144 140 137 133 130 127 124 121 119 116 114 III 109 107 105
0.5g 335 314 296 280 265 253 241 230 220 211 203 195 189 182 176 170 165 160 155 151 147 143 139 135 132 129 125 123 120 117 114 112 N O 108 106 103
10 mg the 1g
333 312 295 278 264 251 239 228 219 210 202 194 187 180 174 168 163 158 153 149 145 141 137 134 130 127 124 121 118 116 113 111 108 106 104 102
m l Fehling's S o l u t i o n deducing Sugars per 100 concentration of s
2g 329 309 291 274 260 249 236 225 216 207 198 191 184 178 171 166 161 156 151 147 143 139 135 131 128 125 122 119 116 114 111 109 106 104 103 100
3g 4g 325 ! 322 305 287 271 257 248 233 222 213 204 196 189 182 175 169 164 159 154 149 145 141 137 133 130 126 123 120 117 115 112 110 107 105 103 102 99
301 284 268 254 242 230 220 210 202 194 186 179 173 167 161 157 152 147 143 139 135 131 128 124 121 118 116 113 110 108 105 103 101 100 98
ml so ution ucrose (g/100 ml) 5g
317 297 280 264 250 238 227 216 207 198 190 183 176 170 165 159 154 149 145 140 136 133 129 126 122 119 116 114 111 108 106 104 102 99 97 95
10g 307 288 271 256 243 231 220 210 200 192 184 177 170 164 159 153 148 143 139 135 131 127 124 120 117 114 III 109 106 103 101 99 96 94 92 90
25g 289 271 255 240 227 217 206 196 187 179 171 164 158 152 147 142 137 132 128 124 121 117 114 111 107 104 102 99 97 94 92 90 88 86 84 82
2 5 m l Fehling's 1 Sol w h e n
is:—
0g
824 772 727 687 651 619 589 563 539
1 517 496 477 460 444 428 414 401 389 377 366 356 346 337 328 320 312 304 297 290 284 278 272 266 261 255 251
Jtion
1g 817 766 722 682 846 614 585 559 534 512 492 473 456 440 424 410 397 385 373 363 352 342 333 325 316 308 301 294 287 281 275 269 263 258 252 248
Laboratory Manual for S. A f r . Sugar Factories 1963 — 79
T A B L E V a
Table giving the divisor, corrected for the brix of the solution, of the formula to be used in the Jackson & Gillis method IV
Corrected Brix Before Dilution
0 1 2 3 4 5 6 7 8 9 10 11 12 13
Divisor 131.60 131.64 131.68 131.72 131.76 131.80 131.84 131.88 1 31.92 13!.97 132.01 132.05 132.10 132.14
Corrected Brix Before Dilution
14 15 16 17 18 19 20 21 22 23 24 25 26
Divisor 132.18 132.23 132.27 132.32 132.36 132.41 132.46 132.50 132.55 132.60 132.64 132.69 132.74
80 — 1963 Laboratory Manual for S. Afr. Sugar Factories
Temperature corrections for
T e m p . ( ° C )
1 5 . 0 15. 1 1 5 . 2 15.3 1 5 . 4 1 5 . 5 1 5 . 6 1 5 . 7 1 5 . 8 1 5 . 9
2 0 . 0 2 0 . 1 2 0 . 2 2 0 . 3 2 0 . 4 2 0 . 5 2 0 . 6 2 0 . 7 2 0 . 8 2 0 . 9 2 1 . 0 21 .1 2 1 . 2 2 1 . 3 2 1 . 4 2 1 . 5 2 1 . 6 2 1 . 7 21 . 8 2 1 . 9 2 2 . 0 2 2 . 1 2 2 . 2 2 2 . 3 2 2 . 4 2 2 . 5 2 2 . 6 2 2 . 7 2 2 . 8 2 2 . 9 2 3 . 0
C o r r e c - tion
2 . 5 0 2 . 4 5 2 . 4 0 2 . 3 5 2 . 3 0 2 . 2 5 2 . 2 0 2 . 15 2 . 1 0 2 . 0 5
0 . 0 0 0 . 0 5 0 . 1 0 0 . 1 5 0 . 2 0 0 . 2 5 0 . 3 0 0 . 3 5 0 . 4 0 0 . 4 5 0 . 5 0 0 . 5 5 0 . 6 0 0 . 6 5 0 . 7 0 0 . 7 5 0 . 8 0 0 . 8 5 0 . 9 0 0 . 9 5 1.00 1.05 1 . 10
! . 15 1.20 1.25 1.30 1.35 1.40 1.45 1 . 5 0
T e m p . ( ° C )
T e 1 6 . 0 16. 1 1 6 . 2 16.3 1 6 . 4 16.5 1 6 . 6 1 6 . 7 1 6 . 8 1 6 . 9 Tem 2 3 . 0 2 3 . 1 2 3 . 2 2 3 . 3 2 3 . 4 2 3 . 5 2 3 . 6 2 3 . 7 2 3 . 8 2 3 . 9 2 4 . 0 2 4 . 1 2 4 . 2 2 4 . 3 2 4 . 4 2 4 . 5 2 4 . 6 2 4 . 7 2 4 . 8 2 4 . 9 2 5 . 0 2 5 . 1 2 5 . 2 2 5 . 3 2 5 . 4 2 5 . 5 2 5 . 6 2 5 . 7 2 5 . 8 2 5 . 9 2 6 . 0
T A B L E V b
the divisors for the Jackson & Gillis method for acid
C o r r e c - tion
T e m p . ( ° C )
C o r r e c - tion
T e m p . ( ° C )
C o r r e c - t i o n m p e r a t u r e c o r r e c t i o n s t o b e added
2 . 0 0 1.95 1.90 1.85 1.80 1.75 1 . 7 0 1.65 1 . 6 0 1.55 p e r a t u r e
1.50 1.55 1 . 6 0 1 .65 1.70 1.75 1.80 1.85 1.90 1.95 2 . 0 0 2 . 0 5 2 . 1 0 2 . 1 5 2 . 2 0 2 . 2 5 2 . 3 0 2 . 3 5 2 . 4 0 2 . 4 5 2 . 5 0 2 . 5 5 2 . 6 0 2 . 6 5 2 . 7 0 2 . 7 5 2 . 8 0 2 . 8 5 2 . 9 0 2 . 9 5 3 . 0 0
1 7 . 0 17.1 1 7 . 2 17.3 1 7 . 4 1 7 . 5 1 7 . 6 1 7 . 7 1 7 . 8 1 7 . 9 correcti
2 6 . 0 2 6 . 1 2 6 . 2 2 6 . 3 2 6 . 4 2 6 . 5 2 6 . 6 2 6 . 7 2 6 . 8 2 6 . 9 2 7 . 0 2 7 . 1 2 7 . 2 2 7 . 3 2 7 . 4 2 7 . 5 2 7 . 6 2 7 . 7 2 7 . 8 2 7 . 9 2 8 . 0 2 8 . 1 2 8 . 2 2 8 . 3 2 8 . 4 2 8 . 5 2 8 . 6 2 8 . 7 2 8 . 8 2 8 . 9 2 9 . 0
1.50 1.45 1 . 4 0 1.35 1.30 1 .25 1.20 1.15 i . 1 0 1.05
1 8 . 0 18.1 1 8 . 2 18.3 1 8 . 4 1 8 . 5 1 8 . 6 1 8 . 7 1 8 . 8 1 8 . 9
1.00 0 . 9 5 0 . 9 0 0 . 8 5 0 . 8 0 0 . 7 5 0 . 7 0 0 . 6 5 0 . 6 0 0 . 5 5 ons to be subtracted
3 . 0 0 3 . 0 5 3 . 1 0 3 . 1 5 3 . 2 0 3 . 2 5 3 . 3 0 3 . 3 5 3 . 4 0 3 . 4 5 3 . 5 0 3 . 5 5 3 . 6 0 3 . 6 5 3 . 7 0 3 . 7 5 3 . 8 0 3 . 8 5 3 . 9 0 3 . 9 5 4 . 0 0 4 . 0 5 4 . 10 4 . 1 5 4 . 2 0 4 . 2 5 4 . 3 0 4 . 3 5 4 . 4 0 4 . 4 5 4 . 5 0
2 9 . 0 2 9 . 1 2 9 . 2 2 9 . 3 2 9 . 4 2 9 . 5 2 9 . 6 2 9 . 7 2 9 . 8 2 9 . 9 3 0 . 0 3 0 . 1 3 0 . 2 3 0 . 3 3 0 . 4 3 0 . 5 3 0 . 6 3 0 . 7 3 0 . 8 3 0 . 9 31 . 0 3 1 . 1 31 . 2 31 .3 3 1 . 4 3 1 . 5 3 1 . 6 3 1 . 7 3 1 . 8 3 1 . 9 3 2 . 0
4 . 5 0 4 . 5 5 4 . 6 0 4 . 6 5 4 . 7 0 4 . 7 5 4 . 8 0 4 . 8 5 4 . 9 0 4 . 9 5 5 . 0 0 5 . 0 5 5 . 1 0 5 . 1 5 5 . 2 0 5 . 2 5 5 . 3 0 5 . 3 5 5 . 4 0 5 . 4 5 5 . 5 0 5 . 5 5 5 . 6 0 5 . 6 5 5 . 7 0 5 . 7 5 5 . 8 0 5 . 8 5 5 . 9 0 5 . 9 5 6 . 0 0
T e m p . (°C)
1 9 . 0 19.1 1 9 . 2 1 9 . 3 1 9 . 4 1 9 . 5 1 9 . 6 1 9 . 7 1 9 . 8 1 9 . 9
3 2 . 0 3 2 . 1 3 2 . 2 3 2 . 3 3 2 . 4 3 2 . 5 3 2 . 6 3 2 . 7 3 2 . 8 3 2 . 9 3 3 . 0 3 3 . 1 3 3 . 2 3 3 . 3 3 3 . 4 3 3 . 5 3 3 . 6 3 3 . 7 3 3 . 8 3 3 . 9 3 4 . 0 3 4 . 1 3 4 . 2 3 4 . 3 3 4 . 4 3 4 . 5 3 4 . 6 3 4 . 7 3 4 . 8 3 4 . 9 3 5 . 0
inversion
C o r r e c - t i o n
0 . 5 0 0 . 4 5 0 . 4 0 0 . 3 5 0 . 3 0 0 . 2 5 0 . 2 0 0 . 1 5 0 . 1 0 0 . 0 5
6 . 0 0 6 . 0 5 6 . 1 0 6 . 1 5 6 . 2 0 6 . 2 5 6 . 3 0 6 . 3 5 6 . 4 0 6 . 4 5 6 . 5 0 6 . 5 5 6 . 6 0 6 . 6 5 6 . 7 0 6 . 7 5 6 . 8 0 6 . 8 5 6 . 9 0 6 . 9 5 7 . 0 0 7 . 0 5 7 . 10 7 . 1 5 7 . 2 0 7 . 2 5 7 . 3 0 7 . 3 5 7 . 4 0 7 . 4 5 7 . 5 0
Millilitres thiosulphate,
N / 1 0
8 . 0 0 8 . 10 8 . 2 0 8 . 3 0 8 . 4 0 8 . 5 0 8 . 6 0 8 . 7 0 8 . 8 0 8 . 9 0 9 . 0 0 9 . 1 0 9 . 2 0 9 . 3 0 9 . 4 0 9 . 5 0 9 . 6 0 9 . 7 0 9 . 8 0 9 . 9 0 1 0 . 0 0 1 0 . 1 0 1 0 . 2 0 1 0 . 3 0 1 0 . 4 0 1 0 . 5 0 1 0 . 6 0 1 0 . 7 0 1 0 . 8 0 1 0 . 9 0 I f . 0 0 1 1 . 1 0 1 1 . 2 0 1 1 . 3 0 1 1 . 4 0 1 1 . 5 0 1 1 . 6 0 1 1 . 7 0 1 1 . 8 0 1 1 . 9 0
T A B L E V I ( c o n t i n u e d )
Milligrams red
1.25 g sucrose
in aliquot
2 4 . 1 0 2 4 . 4 0 2 4 . 7 0 2 5 . 0 0 2 5 . 3 0 2 5 . 6 5 2 5 . 9 5 2 6 . 2 5 2 6 . 5 5 2 6 . 8 5 2 7 . 2 0 2 7 . 5 0 2 7 . 8 0 2 8 . 1 0 28 40 2 8 . 7 0 2 9 . 0 0 2 9 . 3 0 2 9 . 6 0 2 9 . 9 0 3 0 . 2 5 3 0 . 5 5 3 0 . 8 5 3 1 . 2 0 3 1 . 5 0 3 1 . 8 0 3 2 . 10 3 2 . 4 5 3 2 . 7 5 3 3 . 0 5 3 3 . 4 0 3 3 . 7 0 3 4 . 0 0 3 4 . 3 5 3 4 . 6 5 3 4 . 9 5 3 5 . 3 0 3 5 . 6 0 3 5 . 9 0 3 6 . 2 0
sugars 2 - 5 g sucrose
in aliquot
2 3 . 5 5 2 3 . 8 5 2 4 . 15 2 4 . 4 5 2 4 . 7 5 2 5 . 10 2 5 . 4 0 2 5 . 7 0 2 6 . 0 0 2 6 . 3 0 2 6 . 6 5 2 6 . 9 5 2 7 . 2 5 2 7 . 5 5 2 7 . 8 5 2 8 . 2 0 2 8 . 5 0 2 8 . 8 0 2 9 . 1 0 2 9 . 4 0 2 9 . 7 5 3 0 . 0 5 3 0 . 3 5 3 0 . 7 0 3 1 . 0 0 3 1 . 3 5 3 1 . 6 5 3 2 . 0 0 3 2 . 3 0 3 2 . 6 0 3 2 . 9 5 3 3 . 2 5 3 3 . 5 5 3 3 . 9 0 3 4 . 2 0 3 4 . 5 5 3 4 . 8 5 3 5 . 15 3 5 . 5 0 3 5 . 8 0
ucing
5 g sucrose
in aliquot
2 3 . 0 0 2 3 . 3 0 2 3 . 6 0 2 3 . 9 0 2 4 . 2 0 2 4 . 5 0 2 4 . 8 0 2 5 . 1 0 2 5 . 4 0 2 5 . 7 0 2 6 . 0 0 2 6 . 3 0 2 6 . 6 0 2 6 . 9 0 2 7 . 2 0 2 7 . 5 0 2 7 . 8 0 2 8 . 1 0 2 8 . 4 0 2 8 . 7 0 2 9 . 0 5 2 9 . 3 5 2 9 . 6 5 2 9 . 9 5 3 0 . 2 5 3 0 . 6 0 3 0 . 9 0 3 1 . 2 0 31 . 5 0 3 1 . 8 0 3 2 . 1 5 3 2 . 4 5 3 2 . 7 5 3 3 . 0 5 3 3 . 4 0 3 3 . 7 0 3 4 . 0 0 3 4 . 3 5 3 4 . 6 5 3 4 . 9 5
Millilitres thiosulphate,
N / 1 0
1 2 . 0 0 1 2 . 1 0 1 2 . 2 0 1 2 . 3 0 1 2 . 4 0 1 2 . 5 0 1 2 . 6 0 1 2 . 7 0 1 2 . 8 0 1 2 . 9 0 1 3 . 0 0 1 3 . 1 0 1 3 . 2 0 1 3 . 3 0 1 3 . 4 0 1 3 . 5 0 1 3 . 6 0 1 3 . 7 0 1 3 . 8 0 1 3 . 9 0 1 4 . 0 0 1 4 . 1 0 1 4 . 2 0 1 4 . 3 0 1 4 . 4 0 1 4 . 5 0 1 4 . 6 0 1 4 . 7 0 1 4 . 8 0 1 4 . 9 0 1 5 . 0 0 15. 10 1 5 . 2 0 1 5 . 3 0 1 5 . 4 0 1 5 . 5 0 1 5 . 6 0 1 5 . 7 0 1 5 . 8 0 1 5 . 9 0 1 6 . 0 0
Milligrams red
1.25 g sucrose
in aliquot
3 6 . 5 5 3 6 . 8 5 3 7 . 15 3 7 . 5 0 3 7 . 8 0 3 8 . 1 0 3 8 . 4 5 3 8 . 7 5 3 9 . 10 3 9 . 4 0 3 9 . 7 5 4 0 . 0 5 4 0 . 4 0 4 0 . 7 0 4 1 . 0 0 4 1 . 3 5 41 .65 4 2 . 0 0 4 2 . 3 0 4 2 . 6 0 4 2 . 9 5 4 3 . 3 0 4 3 . 6 0 4 3 . 9 5 4 4 . 3 0 4 4 . 6 5 4 5 . 0 0 4 5 . 3 0 4 5 . 6 0 4 5 . 9 5 4 6 . 2 5 4 6 . 6 0 4 6 . 9 0 4 7 . 2 5 4 7 . 6 0 4 7 . 9 5 4 8 . 3 0 4 8 . 6 5 4 9 . 0 0 4 9 . 3 0 4 9 . 6 5
sugars 2 - 5 g sucrose
in aliquot
3 6 . 15 3 6 . 4 5 3 6 . 7 5 3 7 . 0 5 3 7 . 4 0 3 7 . 7 0 3 8 . 0 5 3 8 . 3 5 3 8 . 6 5 3 8 . 9 5 3 9 . 3 0 3 9 . 6 0 3 9 . 9 0 4 0 . 2 5 4 0 . 5 5 4 0 . 9 0 41 . 2 0 4 1 . 5 0 4 1 . 8 5 4 2 . 1 5 4 2 . 5 0 4 2 . 8 0 4 3 . 1 5 4 3 . 4 5 4 3 . 8 0 4 4 . 1 0 4 4 . 4 5 4 4 . 7 5 4 5 . 1 0 4 5 . 4 0 4 5 . 7 5 4 6 . 10 4 6 . 4 0 4 6 . 7 5 4 7 . 10 4 7 . 4 5 4 7 . 8 0 4 8 . 1 5 4 8 . 5 0 4 8 . 8 0 4 9 . 1 5
ucing
5 g sucrose
in aliquot
3 5 . 3 0 3 5 . 6 0 3 5 . 9 0 3 6 . 2 5 3 6 . 5 5 3 6 . 9 0 3 7 . 2 0 3 7 . 5 0 3 7 . 8 5 3 8 . 15 3 8 . 5 0 3 8 . 8 0 3 9 . 15 3 9 . 4 5 3 9 . 8 0 4 0 . 1 0 4 0 . 4 0 4 0 . 7 5 4 1 . 1 0 4 1 . 4 0 4 1 . 7 0 4 2 . 0 0 4 2 . 3 5 4 2 . 6 5 4 3 . 0 0 4 3 . 3 0 4 3 . 6 5 4 4 . 0 0 4 4 . 3 0 4 4 . 6 5 4 4 . 9 5 4 5 . 3 0 4 5 . 6 5 4 6 . 0 0 4 6 . 3 0 4 6 . 6 5 4 7 . 0 0 4 7 . 3 5 4 7 . 7 0 4 8 . 0 0 4 8 . 3 0
Laboratory Manual for S. Afr. Sugar Factories 1962 — 83
Product Final bagasse
First expressed juice
Mixed juice
Last expressed juice
Sulphited juice (sulphur tower) Clarified juice
Filter juice (clear filtrate)
Filter cake
Syrup
Massecuite
Molasses (run-off)
Wash
Final Molasses
Sugar
Method of Sampling Catch
Continuous
Continuous automatic
Continuous
Catch Continuous
Catch
Catch
Catch
Catch
Catch when crystal- lizer about 1/3 down Catch from tank
Continuous
Semi-continuous
Period covered by sample 1/4 hour
1 hour
1 hour
1/4 hour
2 hours 1 hour
1 hour
1 hour
1 hour (from every tank)
Every strike (at the discharge) Every crystallizer
8 hours
24 hours
1 hour
Composite sample 1 hour
4-hour sample to be pre- served in mill lab.
4-hour sample consisting of aliquot parts of 1 hr.
samples
4-hour sample, preserva- tive added
No
4-hour sample, preserva- tive added
No No 4-hour sample
No No No 6 days
Procedure followed depen
Analysis carried out on primary sample
—
Pol Brix Pol
Brix, before addition of lead subacetate
—
S02
pH Pol Brix Pol Moisture
—
Pol Brix Pol Brix Pol Brix
—
ds on the circumstances
Analysis carried out on composite sample Pol
Moisture Pol Pol Sucrose Red. sugars Pol Brix
-
Pol Brix
~ -
Pol Brix Red.sugars
—
—
—
Pol, brix, sucrose, Red sugars, sulph. ash