APPENDIX I
APPENDIX II
THE DETERMINATION OF THE POLARISATION OF EXPORT SUGARS Wet Lead defecation method:
This method should be used for all export sugars.
26.00 grams of the sample are rinsed with water into a 100 ml. flask. When the sugar has been dissolved by swirling the flask, the volume is brought up to 90 ml. and the solution clarified by the addition of 0.5 to 0.7 ml. of basic lead acetate solution (see page 29), after which the procedure outlined on page 20 is followed.
(a) Polarisation by Saccharimeter:
The value to be finally reported is derived as in the following example:- Reading Tube filled with distilled water (mean of five readings) .... 0.07° (1) Instrument trough empty (mean of five readings) 0.05° (2) Sugar Solution (mean of five readings) 96.64° (3) :.mean reading of solutions corrected for instrument error (3—1) .. .. 96.57° (4)
Temperature of observations 28°C.
Quartz plate value certified at 20°C 95.97° (5) Quartz plate temperature correction* corresponding to 28°C +0.24° (6) :. Quartz plate value adjusted to 28°C. (5)+(6) 96.21° (7) Instrument reading of Quartz Plate (mean of five readings) 95.92° (8) Quartz plate readings (8) corrected for instrument error (8) — (2) .. .. 95.87° (9) Correction to bring (4) to 20°C. (7) - (9) +0.34° (10) :. Polarisation corrected to 20°C. and reported as such (4) + (10) .. .. 96.91 ° (b) Polarisation by Polarimeter:
The simple optical train of the circle polarimeter ensures maintenance of adjustment and eliminates inaccuracies of scale calibration due to irregularities in the rotation of quartz wedges or fluctuations in temperature. Provided therefore that the instrument is properly adjusted, it is not necessary to check each polarisation with reference to a quartz wedge. Consequently, apart from any instrument error, the only significant correction necessary for temperature is that due to the influence of temperature on the optical rotation of the mixture of sucrose and the other sugars in raw sugars. These consi- derations explain the form of an empirical relationship due to C.A. Browne such that:
% error due to temperature = 0.0015 (P - 80)(t - 20)
where P = the purity of the raw sugar and t is the temperature in °C. at which the polarisation is carried out. Lane and Eynon (in a private communication) recommended that for raw sugars, a correction of + 0.02 per °C. above 20°C. is adequate in view of the usual invert sugar content of raw sugars.
* Taken from the temperature correction table supplied with each quartz control plate.
The value to be reported is therefore derived in the following manner- Reading Tube filled with distilled water (mean of five readings) 0.004° (1) Sugar solution (mean of five readings) 96.816° (2) Sugar solution corrected for instrument error (2) —(1) 96.812° (3) Temperature of observations 28°C (4) Temperature correction corresponding to 28°C. (8 x 0.02) +0.160° (5) :. Polarisation corrected to 20°C. and reported as such (3) + (5) 96.972°
If the instrument is checked by means of a quartz plate, it should be borne in mind that the table of temperature corrections given with quartz plates is based upon -
st = St = S2 0 [1 + 0.0003 (t - 20) ]
and refers to the readings which sucrose solutions (reading the same as the quartz plate at 20°C.) would give if read in a saccharimeter at t° C For checking a polarimeter, what is required is the reading which the quartz plate would register in a polarimeter at t° C, and this is given by adding 0.0143 (t - 20).
20°C.
The polarimeter can also be checked by using the purest sucrose available, which should be not less pure than 99.98% pure sucrose. The sugar should be dried in a Spencer oven for 20 minutes at 110°C. and cooled in a desiccator before weighing.
NOTE: Whether a saccharimeter or polarimeter is used, the light must be filtered through an amber coloured filter which is equivalent to 30 mm, of a 3% potassium bichromate solution.
APPENDIX III
THE ACTIVITY OF INVERTASE CONCENTRATE
NOTE: Invertase requires storage at 40°F. and frequent checking of its activity is necessary.
Method:
Prepare the following solutions:
(1) Dilute 1 ml. of the Invertase concentrate to 200 ml. with distilled water.
(2) Dissolve 10 gm. of pure sucrose in distilled water and transfer to a graduated 100/110 ml. flask, acidify with two drops of glacial acetic acid and make to the 100 ml. graduation with distilled water.
Add 10 ml. of solution 1 to solution 2 and mix thoroughly; allow to stand for 60 minutes at room temperature (20°C). Make a portion of this solution alkaline to litmus paper by the addition of anhydrous sodium carbonate and polarise in a 200 mm. tube. If the diluted Invertase solution is of standard activity, a sugar solution polarising at 31.0° Pol would be given, without correct- ion for the volume increase from 100 to 110 ml., or for any optical activity of the Invertase. Invertase of this nature should give the following degree of inversion:
Calculation:
10 gm. Sucrose in 110 ml. has a Pol of 34.96°: when completely inverted the Pol should be - 11.22°, thus giving a drop in Pol of 34.96° + 11.22 = 46.18°, i.e. % drop caused by the correct activityof the invertase
is 100 x (34.96 - 31,00) = 8.58%
46.18
If, however, a Pol of 26.00° is obtained on the partially inverted sucrose in the determination, the
% drop in Pol = (34.96 - 26.00) x l00 = 19.40%
46.18
A activity of our Invertase = 19.40 = 2.26 8.58
Since 10 ml. of normal activity invertase solution as prepared above (or 5 ml. of the 1% solution), are required for inversion, then the volume of 2.26 activity invertase required is 4.42 ml.
APPENDIX IV (a)
APPENDIX IV (b)
TABLE II
POLARIZATION FROM POLARISCOPE READING (WITHOUT DILUTION) AND DEGREE BRIX
For use with Solutions prepared with Dry Subacetate of Lead and Brix Hydrometer standardised at 27.5°C. or Refractometer
TABLE II (Contd.)
TABLE NO. II (Contd.)
TABLE II (Contd) Degree Brix 7.5 - 13.0
TABLE II (Contd.)
TABLE II (Contd.)
TABLE III
TABLE IV
TABLE VI
TABLE VII
BRIX, SPECIFIC GRAVITY, WEIGHT/UNIT VOLUME 27 1/2 °C
TABLE VII (Contd.)
TABLE VII (Contd.)
TABLE VII (Contd.)
TABLE VII (Contd.)
TABLE VIII
TABLE VIII (Contd.)
TABLE VIII (Contd.)
TABLE VIII (Contd.)
TABLE X
LIME SLURRIES CONCENTRATIONS (at l5°C, (59°F))
TABLE IX SODIUM HYDROXIDE SOLUTIONS
BRIX %
TABLE XI
CRYSTAL CONTENT OF MASSECUITE (% BRIX)
To convert to Crystal Content % Volume multiply by °Brix
TABLE XII CONVERSION FACTORS
TABLE XII Conversion Factors (Contd.)
Kilograms/meter lbs. ft. 0.67197
TABLE XII Conversion Factors (Contd.)
TABLE XII Conversion Factors (Contd.)
Sugars — For all sugars the value 132.63 at 20° C. may be adopted.
Molasses — For normal samples of molasses the value 131.88 at 20° C. may be adopted.
For other materials or other methods of inversion the divisor must be calculated from the specific data. All Clerget divisors must be corrected for temperature according to the table.
TABLE XIII - Clerget Divisors.
When analyses are conducted according to Jackson Gillis Method IV, the presently accepted formula for conversion of polariscope readings to sucrose concentration is:-
S = 100 ( P - P1)
132.63 + 0.0794 (m - 13) - 0.53 (t - 2 0 ) where S = Sucrose per cent in sample
P = direct reading calculated to basis of normal solution P1 = Invert reading calculated to basis of normal solution
m = concentration of dissolved solids in g. per 100 ml. of solution as read in polariscope
t = temperature in °C.
The basic value of 132.63 applies to the Walker method of inversion (heat to 65° C, add acid, allow to cool). For inversion by the U.S. Customs method (add acid, immerse in 60° C. bath, stir for 3 min., hold 7 more min., cool quickly) the basic value is 132.56, whilst for inversion at room temperature (24 hr.) the value is 132.66.
For Invertase inversion the Clerget divisor is given by the formula - 132.1 + 0.0833 (m - 13) - 0.53 (t - 20).
Using the Walker method of inversion some useful Clerget divisors, at 20° C, are:
Juices — The divisor is related to the brix as follows:
TABLE XIII (a)
TABLE XIII(B)
Subtractive Temperature Corrections for Clerget Divisors.
TABLE XIV
TEMPERATURE CORRECTIONS F O R BASIC CLERGET DIVISOR ( 0 . 5 3 t )
177
TABLE XV
INTERNATIONAL ATOMIC WEIGHTS, 1966 Published by the C.R.E. Handbook of Chemistiy and Physics