High Fructose Corn Syrup
» High Fructose Corn Syrup is a sweet, nutritive saccharide mixture prepared as a clear, aqueous solution from high-dextrose-equivalent corn starch hydrolysate by the partial enzymatic conversion of dextrose to fructose, using an insoluble glucose isomerase enzyme preparation that complies with 21 CFR 184.1372. It is available in two types, 42% and 55%, based on fructose content. High Fructose Corn Syrup 42% contains not less than 97.0 percent of total saccharides, expressed as a percentage of total solids, of which not less than 92.0 percent consists of monosaccharides (fructose and dextrose), including not less than 41.5 percent and not more than 44.8 percent of fructose, and not more than 8.0 percent consists of other saccharides. High Fructose Corn Syrup 55% contains not less than 95.0 percent of total saccharides, expressed as a percentage of total solids, of which not less than 95.0 percent consists of monosaccharides (fructose and dextrose), including not less than 54.5 percent and not more than 56.5 percent of fructose, and not more than 5.0 percent consists of other saccharides.
Packaging and storage Preserve in tight containers. No storage requirement specified.
Labeling Label it to state, as part of the official title, the nominal percentage of fructose, based on the specified minimum percentage concentration of total saccharides. Label it to indicate the presence of sulfur dioxide if the residual sulfur dioxide concentration is greater than 10 µg per g.
Identification Add a few drops of a solution (1 in 10) of Syrup to 5 mL of hot, alkaline cupric tartrate TS: a copious, red precipitate of cuprous oxide is formed (distinction from sucrose).
Microbial enumeration tests 61 and Tests for specified microorganisms 62 The total aerobic microbial count does not exceed 1000 cfu per g, and the total combined molds and yeasts count does not exceed 100 cfu per g.
Residue on ignition 281: not more than 0.05%.
Heavy metals, Method II 231: not more than 5 µg per g, an ignition temperature of 500 being used.
Total solids Determine the refractive index of Syrup at 20 or 45 (see Refractive Index 831). Use the table below for calculating the percentage of dry substance (percentage of total solids).
Limit of sulfur dioxide Transfer about 100 g of Syrup, accurately weighed, to a 250-mL conical flask, add 100 mL of water, and mix. Cool to between 5 and 10. While stirring with a magnetic stirrer, add 10 mL of cold 1.5 N sodium hydroxide (at a temperature between 5 and 10). Stir for an additional 20 seconds, and add 10 mL of starch indicator solution prepared as follows. Mix 10 g of soluble starch with 50 mL of cold water, transfer to 1000 mL of boiling water, stir until completely dissolved, cool, and add 1 g of salicylic acid preservative. [noteDiscard the solution after 1 month.] Add 10 mL of 2.0 N sulfuric acid (at a temperature between 5 and 10), and titrate immediately with 0.005 N iodine VS until a light blue color persists for 1 minute (see Titrimetry 541). Perform a blank determination, using 200 mL of water treated similarly to the solution under test, and make any necessary correction. Each mL of 0.005 N iodine is equivalent to 0.16 mg of SO2: not more than 30 µg per g is found.
Limit of lead [noteFor the preparation of all aqueous solutions and for the rinsing of glassware before use, employ water that has been passed through a strong-acid, strong-base, mixed-bed ion-exchange resin before use. For digestion, use acid-cleaned, high-density polyethylene, polypropylene, polytef, or quartz tubes. Select all reagents to have as low a content of lead as practicable, and store all reagent solutions in borosilicate glass containers. Cleanse glassware before use by soaking in warm 8 N nitric acid for 30 minutes and rinsing with deionized water. Store final diluted solutions in acid-cleaned plastic or polytef tubes or bottles.]
Modifier solution Prepare a solution of magnesium nitrate in water containing about 200 mg per mL. Just before use, transfer 1.0 mL of this solution to a 10-mL volumetric flask, dilute with 5% nitric acid to volume, and mix.
Standard solutions Transfer 10.0 mL of Lead Nitrate Stock Solution, prepared as directed under Heavy Metals 231, to a 100-mL volumetric flask, add 40 mL of water and 5 mL of nitric acid, dilute with water to volume, and mix. Transfer 1.0 mL of this solution to a second 100-mL volumetric flask, dilute with 5% nitric acid to volume, and mix. This solution contains 0.1 µg of lead per mL. Transfer portions of this solution to four suitable containers, and dilute quantitatively, and stepwise if necessary, with 5% nitric acid to obtain Standard solutions having lead concentrations of 100 ng per mL, 50 ng per mL, 25 ng per mL, and 10 ng per mL, respectively.
Test solution [notePerform this procedure in a fume hood.] Transfer about 1.5 g of Syrup, accurately weighed, to two digestion tubes, labeled Test solution and Temperature monitor solution, and add 0.75 mL of nitric acid to each tube. Warm both solutions slowly to between 90 and 95 to avoid spattering. Heat until all brown vapors have dissipated and any rust-colored tint is gone from the tube labeled Test solution (20 to 30 minutes). Cool, add 0.5 mL of 50% hydrogen peroxide dropwise to both solutions, heat to between 90 and 95 for 5 minutes, and cool. Add a second 0.5-mL portion of 50% hydrogen peroxide dropwise to each solution, and heat to between 90 and 100 for 5 to 10 minutes until the tube labeled Test solution is clear. Cool, and transfer the Test solution to a 10-mL volumetric flask. Rinse the tube labeled Test solution with 5% nitric acid, add the rinsing to the volumetric flask, dilute with 5% nitric acid to volume, and mix.
Standard blank Use 5% nitric acid.
Test blank Transfer 1.5 g of water to a digestion tube, and proceed as directed for the Test solution, beginning with add 0.75 mL of nitric acid.
Procedure [noteUse peak area measurements for all quantitations.] Add 5 µL of the Modifier solution to 20 µL each of the Standard solutions, the Test solution, the Standard blank, and the Test blank, and mix. Separately inject equal volumes (about 20 µL) of the Standard solutions, the Test solution, the Standard blank, and the Test blank into a suitable graphite furnace atomic absorption spectrophotometer equipped with pyrolytically coated graphite tubes and adequate means of background correction. The temperature is programmed as follows. Maintain the drying temperature of the furnace at 200 for 30 seconds after a 20-second ramp time using an argon gas flow of about 300 mL per minute; maintain the ashing temperature at 750 for 40 seconds after a 40-second ramp time using an airflow of about 300 mL per minute; cool down and purge the air from the furnace for 60 seconds using a 20 set temperature and an argon gas flow of about 300 mL per minute; and maintain the atomization temperature at 1800 for 10 seconds after a 0-second ramp time with the argon gas flow stopped. [noteThe temperature program may be modified to obtain optimum furnace temperatures.] Using the Standard blank to set the instrument to zero, determine the integrated absorbances of the Standard solutions at the lead emission line at 283.3 nm. Plot the integrated absorbances of the Standard solutions versus their contents of lead, in ng per mL, and draw the line best fitting the four points to determine the calibration curve. Similarly determine the integrated absorbances of the Test solution and the Test blank at the lead emission line at 283.3 nm. Correct the absorbance value of the Test solution by subtracting from it the absorbance value obtained from the Test blank. Calculate the concentration, in µg per g, of lead in the portion of Syrup taken by the formula:
0.01(C/W)in which C is the concentration, in ng per mL, of lead in the Test solution, as determined from the calibration curve; and W is the weight, in g, of Syrup taken to prepare the Test solution: the limit is 0.1 µg per g.
Mobile phase Use filtered and degassed water.
Standard preparation Prepare a solution in water containing a total of about 10% saccharide solids of USP Dextrose RS, USP Fructose RS, and USP Maltose Monohydrate RS, in which the USP Dextrose RS and USP Fructose RS percentage concentrations are in the same ratio as those in the Assay preparation, based on the labeled nominal fructose percentage for the Syrup under test. Calculate the percentage of USP Maltose Monohydrate RS by the formula:
100 (F + D)in which F is the labeled nominal fructose percentage for the Syrup under test; and D is the difference between the specified minimum percentage concentration of total monosaccharides for the Syrup and F.
Assay preparation Dilute a known volume of Syrup, determined from the results of the test for Total solids and on the nominal total saccharides content, with water to a total saccharides concentration of about 10% (w/v), and mix.
Chromatographic system (see Chromatography 621) The liquid chromatograph is equipped with a refractive index detector maintained at 45 and a 7.8-mm × 30-cm column that contains packing L19. The column is maintained at a constant temperature of about 85. The flow rate is about 0.6 mL per minute. Chromatograph the Standard preparation, and record the peak areas as directed for Procedure: the relative retention times are about 0.83, 1.0, and 1.32 for maltose, dextrose, and fructose, respectively; and the resolution, R, between maltose and dextrose is not less than 1.2.
Procedure Separately inject equal volumes (about 10 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the areas for the major peaks. Calculate the percentage of fructose and of dextrose in the portion of Syrup taken by the formula:
100C(VA / VS S1S2)(rU / rS)in which C is the concentration, in mg per mL, of USP Fructose RS or USP Dextrose RS in the Standard preparation; VA is the volume, in mL, of the Assay preparation; VS is the volume, in mL, of Syrup taken to prepare the Assay preparation; S1 is the percentage of total saccharides in the Standard preparation (corresponding to 97 for High Fructose Corn Syrup 42% and to 95 for High Fructose Corn Syrup 55%); S2 is the percentage of total solids in the Syrup as determined in the test for Total solids; and rU and rS are the peak areas of fructose or dextrose obtained from the Assay preparation and the Standard preparation, respectively. Calculate the percentage of other saccharides, expressed in terms of maltose, in the portion of Syrup taken by the formula:
C(rU / rS)in which C is the concentration, in mg per mL, of USP Maltose Monohydrate RS in the Standard preparation; rU is the sum of all peak areas obtained from the Assay preparation, except those of fructose and dextrose; and rS is the peak area of maltose obtained from the Standard preparation.
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USP32NF27 Page 1214Pharmacopeial Forum: Volume No. 34(2) Page 329
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.