Packaging and storage
Preserve in tight, light-resistant containers.
Identification
Solution:
10 µg per mL.
Medium:
pH 7.5 phosphate buffer, prepared by mixing 21 volumes of 0.15 M dibasic sodium phosphate and 4 volumes of 0.15 M monobasic potassium phosphate.
Ratio:
A405/A630, between 3.0 and 3.9
Microbial limits
61
It meets the requirements of the tests for absence of
Escherichia coli and
Salmonella species.
pH
791
:
between 9.5 and 10.7, in a solution (1 in 100).
Test for fluorescence
Apply 10 µL of a 1% solution of it on filter paper, allow to dry, and examine the area of application under long-wavelength UV light through a red optical filter: no fluorescence is visible.
Limit of ionic copper
Test solution
Transfer about 100 mg of Chlorophyllin Copper Complex Sodium, accurately weighed, to a 150-mL conical flask, add 75 mL of water, and shake by mechanical means for about 3 minutes. Adjust with 1 N hydrochloric acid to a pH of 3.0, transfer the suspension thus obtained to a 100-mL volumetric flask, dilute with water to volume, and mix. Filter this suspension, discarding the first 10 mL of the filtrate. Use the clear filtrate as the Test solution.
Procedure
Proceed as directed for
Procedure in the test for
Content of total copper. Calculate the percentage of ionic copper in the portion of Chlorophyllin Copper Complex Sodium taken by the formula:
10C / W,
in which the terms are as defined therein: not more than 0.25% is found, calculated on the dried basis.
Content of chelated copper
Calculate the percentage of chelated copper in the portion of Chlorophyllin Copper Complex Sodium taken by subtracting the percentage of ionic copper found in the test for
Limit of ionic copper from the percentage of total copper found in the test for
Content of total copper, calculated on the dried basis: not less than 4.0% is found.
Content of total copper
Copper stock solution
Transfer 1.000 g of copper to a 1000-mL volumetric flask, dissolve in 20 mL of nitric acid, dilute with 0.2 N nitric acid to volume, and mix. This solution contains 1000 µg of copper per mL. Store in a polyethylene bottle.
Standard solutions
Pipet 5.0 mL of Copper stock solution into a 500-mL volumetric flask, dilute with water to volume, and mix. Transfer 5.0, 10.0, 15.0, and 20.0 mL, respectively, of this solution to separate 100-mL volumetric flasks, dilute the contents of each flask with water to volume, and mix. These Standard solutions contain 0.5, 1.0, 2.0, and 3.0 µg of copper per mL, respectively.
Test solution
Transfer about 100 mg of previously dried Chlorophyllin Copper Complex Sodium, accurately weighed, to a Kjeldahl flask. Add 2.0 mL of sulfuric acid, 1.0 mL of nitric acid, and 1.0 mL of hydrogen peroxide, and carefully heat under a fume hood until a light green color is obtained. [NOTEIf the solution has any hint of a brown tint, continue to add 0.5-mL portions of nitric acid until a green color is obtained.] Cool, transfer the contents quantitatively to a 1000-mL volumetric flask with several portions of water, dilute the contents of the flask with water to volume, and mix. Transfer 10.0 mL of this solution to a 50-mL volumetric flask, dilute with water to volume, and mix.
Procedure
Concomitantly determine the absorbances of the
Standard solutions and the
Test solution at the copper emission line of 324.8 nm with an atomic absorption spectrophotometer (see
Spectrophotometry and Light-Scattering
851![](images/chars/rang.gif)
) equipped with a copper hollow-cathode lamp and an airacetylene flame, using water as the blank. Plot the absorbances of the
Standard solutions versus the concentration, in µg per mL, of copper, and draw the straight line best fitting the four plotted points. From the graph so obtained, determine the concentration,
C, in µg per mL, of copper in the
Test solution. Calculate the percentage of copper in the portion of Chlorophyllin Copper Complex Sodium taken by the formula:
500C / W,
in which
W is the weight, in mg, on the dried basis, of Chlorophyllin Copper Complex Sodium taken to prepare the
Test solution, not less than 4.25% is found.
Content of sodium
Standard stock solution
Dissolve 254.2 mg of sodium chloride, previously dried at 105
![](images/chars/deg.gif)
for 2 hours, in 50 mL of water, transfer to a 1000-mL volumetric flask, dilute with water to volume, and mix. Each mL of this solution contains 100 µg of sodium.
Standard solutions
Transfer to each of five 100-mL volumetric flasks 10 mL of a solution of a nonionic wetting agent (1 in 500). Dilute the contents of one of the flasks with water to volume to provide a blank. To the remaining flasks add, respectively, 2.5, 5.0, 10.0, and 15.0 mL of the Standard stock solution, dilute with water to volume, and mix. These Standard solutions contain 2.5, 5.0, 10.0, and 15.0 µg of sodium per mL, respectively.
Test solution
Transfer about 100 mg of Chlorophyllin Copper Complex Sodium, accurately weighed, to a 1000-mL volumetric flask, add 100 mL of a solution of nonionic wetting agent (1 in 500) and 400 mL of water, and shake by mechanical means for about 5 minutes. Dilute with water to volume, and mix.
Standard graph
Set the flame photometer for maximum transmission at a wavelength of about 589 nm. Adjust the instrument to zero transmittance with the blank. Adjust the instrument to 100% transmittance with the most concentrated of the Standard solutions. Read the percentage of transmittance of the other Standard solutions, and plot the percentage of transmittance versus the concentration, in µg per mL, of sodium.
Procedure
Adjust the instrument as directed under
Standard graph, read the percentage of transmittance of the
Test solution, and from the
Standard graph read the concentration,
C, in µg per mL, of sodium in the
Test solution. Calculate the percentage of sodium in the portion of Chlorophyllin Copper Complex Sodium taken by the formula:
100C / W,
in which
W is the weight, in mg, of Chlorophyllin Copper Complex Sodium taken to prepare the
Test solution: between 5% and 7%, calculated on the dried basis, is found.