Calcium Propionate
C6H10CaO4 186.22
[4075-81-4].
C6H10CaO4 186.22
[4075-81-4].DEFINITION
Calcium Propionate contains NLT 98.0% and NMT 100.5% of C6H10CaO4, calculated on the anhydrous basis.
IDENTIFICATION
• Identification Tests—General, Calcium 
191
:
A solution (1 in 20) meets the requirements of the flame test.
191:
A solution (1 in 20) meets the requirements of the flame test.
ASSAY
• Procedure
Sample solution:
4 mg/mL of Calcium Propionate
Analysis:
While stirring, preferably with a magnetic stirrer, add 30 mL of 0.05 M disodium EDTA from a 50-mL buret, to 100 mL of Sample solution. Add 15 mL of 1 N sodium hydroxide and 300 mg of hydroxy naphthol blue indicator, and continue the titration to a blue endpoint. Each mL of 0.05 M disodium EDTA is equivalent to 9.311 mg of C6H10CaO4.
Acceptance criteria:
98.0%–100.5% on the anhydrous basis.
IMPURITIES
Inorganic Impurities
• Limit of Fluoride
Buffer:
294.1 mg/mL of sodium citrate dihydrate
Standard solution:
2.21 mg/mL of USP Sodium Fluoride RS. [Note—Store solution in a plastic bottle. ] On the day of use, transfer 5.0 mL of the resulting solution to a 1000-mL volumetric flask, dilute with water to volume, and mix. Each mL of this solution contains 5 µg of fluoride ion.
Electrode system:
Use a fluoride-specific, ion-indicating electrode and a silver–silver chloride reference electrode connected to a pH meter capable of measuring potentials with a minimum reproducibility of ±0.2 mV (see pH 791).
791).
Standard response line:
Transfer 1.0, 2.0, 3.0, 5.0, 10.0, and 15.0 mL of the Standard solution into separate 250-mL plastic beakers. Add 50 mL of water, 5 mL of 1 N hydrochloric acid, 10 mL of Buffer, and 10 mL of 0.2 M disodium EDTA to each beaker, and mix. Transfer each solution into separate 100-mL volumetric flasks, dilute with water to volume, and mix. Transfer a 50-mL portion of each solution into separate 125-mL plastic beakers, and read the potential, in mV, of each solution using the electrode system. Plot the calibration curve versus potential, in mV, on two-cycle semilogarithmic paper with µg of fluoride/100 mL of solution on the logarithmic scale.1
Sample:
1.0 g
Analysis:
Transfer the Sample into a 150-mL glass beaker, add 10 mL of water, and, while stirring continuously, slowly add 20 mL of 1 N hydrochloric acid to dissolve the Sample. Boil rapidly for 1 min, then transfer into a 250-mL plastic beaker, and cool rapidly in ice water. Add 15 mL of Buffer and 10 mL of 0.2 M disodium EDTA, and mix. Adjust the pH to 5.5 ± 0.1 with 1 N hydrochloric acid or 1 N sodium hydroxide, if necessary. Transfer into a 100-mL volumetric flask, dilute with water to volume, and mix. Transfer a 50-mL portion of this solution into a 125-mL plastic beaker, and record the potential using the electrode system. Determine the concentration of fluoride, in µg/mL, in the Sample.
Acceptance criteria:
NMT 30 ppm
• Limit of Lead
Standard lead solution:
Prepare as directed under Heavy Metals 231, Special Reagents.
231, Special Reagents.
Diluted standard lead solutions:
On the day of use, transfer 5.0, 10.0, and 20.0 mL of Standard lead solution into three separate 100-mL volumetric flasks, add 10 mL of 3 N hydrochloric acid to each, and dilute with water to volume corresponding to 0.5-, 1.0-, and 2.0-µg/mL standards.
25% Sulfuric acid solution:
Cautiously add 100 mL of sulfuric acid to 300 mL of water with constant stirring while cooling in an ice bath.
Sample blank:
Add 5 mL of 25% Sulfuric acid solution into an evaporating dish. Within a hood, place the dish on a steam bath to evaporate most of the water. Place the dish on a burner, and slowly pre-ash the sample by expelling most of the sulfuric acid. Place the dish in a muffle furnace that has been set at 525
, and ash the sample until the residue appears free from carbon. Cool, and cautiously wash down the inside of the evaporation dish with water. Add 5 mL of 1 N hydrochloric acid. Place the dish on a steam bath, and evaporate to dryness. Add 1.0 mL of 3 N hydrochloric acid and approximately 5 mL of water, and heat briefly on a steam bath to dissolve any residue. Transfer the solution quantitatively to a 10-mL volumetric flask, dilute to volume, and mix.
, and ash the sample until the residue appears free from carbon. Cool, and cautiously wash down the inside of the evaporation dish with water. Add 5 mL of 1 N hydrochloric acid. Place the dish on a steam bath, and evaporate to dryness. Add 1.0 mL of 3 N hydrochloric acid and approximately 5 mL of water, and heat briefly on a steam bath to dissolve any residue. Transfer the solution quantitatively to a 10-mL volumetric flask, dilute to volume, and mix.
Sample solution:
Place 10 g of Calcium Propionate, to the nearest 0.1 mg, into an evaporating dish. Add a sufficient amount of 25% Sulfuric acid solution, and distribute the sulfuric acid uniformly through the sample. Proceed as directed under Sample blank beginning with “Within a hood”.
Spectrometric conditions
Mode:
Atomic absorption
Lamp:
Lead electrodeless discharge
Flame:
Air–acetylene
Analytical wavelength:
283.3 nm
Slit width:
0.7 nm
Instrument blank:
Water
Standard curve
Samples:
Diluted standard lead solutions and Sample blank
Plot:
Corrected absorbance values versus their corresponding concentration (µg/mL). [Note—Determine corrected absorbance values by subtracting the absorbance of the Sample blank from the absorbance of the Diluted standard lead solutions. ]
Analysis
Samples:
Sample solution and Sample blank
[Note—Determine corrected absorbance values by subtracting the absorbance of the Sample blank from the absorbance of the Sample solution. ]
From the Standard curve, determine the lead concentration in the Sample solution. Calculate the lead content, in ppm, in the portion of Calcium Propionate taken:
Result = CS/W × V
| CS | = | = concentration of lead from the Standard curve (µg/mL) |
| W | = | = weight of the sample taken (g) |
| V | = | = final volume of the sample (mL) |
Acceptance criteria:
NMT 2 ppm
• Magnesium (as MgO)
Magnesium standard solution:
Dissolve 50.0 mg of magnesium metal in 1 mL of hydrochloric acid in a 1000-mL volumetric flask, dilute with water to volume, and mix.
Sample solution:
Place 400.0 mg of Calcium Propionate, 5 mL of 2.7 N hydrochloric acid, and about 10 mL of water in a small beaker, and dissolve the Calcium Propionate by heating on a hot plate.
Analysis:
Evaporate the Sample solution to a volume of about 2 mL, and cool. Transfer the residual liquid into a 100-mL volumetric flask, dilute with water to volume, and mix. Dilute 7.5 mL of this solution with water to 20 mL, add 2 mL of 1 N sodium hydroxide and 0.05 mL of a 1:1000 solution of thiazole yellow, mix, allow to stand for 10 min, and shake. Any color produced does not exceed that produced by 1.0 mL of Magnesium standard solution in the same volume as that of a control containing 2.5 mL of the Sample solution (corresponding to 10 mg of Calcium Propionate) and the quantities of the reagents used in the test.
Acceptance criteria:
The solution passes the test (about 0.4%).
SPECIFIC TESTS
• Water Insoluble Substances
Sample:
10 g
Analysis:
Dissolve the Sample in 100 mL of hot water, pass through a tared filtering crucible, wash the insoluble residue with hot water, and dry at 105 to constant weight.
to constant weight.
Acceptance criteria:
NMT 0.2%
• pH 791:
7.5–10.5, in a solution (1 in 10)
791:
7.5–10.5, in a solution (1 in 10)
• Water Determination, Method I 921:
NMT 5.0%
921:
NMT 5.0%
• Loss on Drying 731:
Dry a sample at 105 for 2 h: it loses NMT 4% of its weight.
731:
Dry a sample at 105 for 2 h: it loses NMT 4% of its weight.
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Store in tightly closed containers. No storage requirements specified.
• USP Reference Standards 11
11
USP Sodium Fluoride RS
1
A suitable source for semilogarithmic paper is provided at the following website: http://statland.org/GraphPaper/gpaper.html.
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Robert H. Lafaver, M.S.
Scientific Liaison 1-301-816-8335 |
(EXC2010) Monographs - Excipients |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 1720
Pharmacopeial Forum: Volume No. 34(6) Page 1517