A: The retention times of the quinic acid,malic acid,and citric acid peaks in the chromatogram of the Test solutioncorrespond to those in the chromatogram of the Standard solution,as obtained in the test for Content of organic acids.

B: Absence of adulterants—

Standard solution— Dissolve accurately weighed quantities of tartaric acid and fumaric acid in water to obtain a solution having known concentrations of about 1.0and 0.1mg per mL,respectively.

Test solution— Use the Liquid Preparation.

Mobile phase and Chromatographic system—Proceed as directed for Content of organic acids.

Procedure— Separately inject equal volumes (about 20µL)of the Standard solutionand the Test solutioninto the chromatograph,and record the chromatograms.The retention times of the tartaric acid and fumaric acid peaks in the chromatogram of the Standard solutiondo not correspond to any of the retention times for peaks observed in the chromatogram of the Test solution.

Mobile phase and Test preparation—Prepare as directed for Content of dextrose and fructose.

Standard preparation— Dissolve accurately weighed quantities of USP Sorbitol RSand USP Sucrose RSin water to obtain a solution having known concentrations of about 0.5mg of each Reference Standard per mL.

Chromatographic system— Proceed as directed for Content of dextrose and fructose.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the relative retention times are about 0.4for sucrose and 1.0for sorbitol;the resolution,R,between sucrose and sorbitol peaks is not less than 1.8;and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 20µL)of the Standard preparationand the Test preparationinto the chromatograph,record the chromatograms,and measure the areas of the peaks.Calculate the percentages of sucrose and sorbitol in the volume of Liquid Preparation taken by the formula: in which Cis the concentration,in mg per mL,of the appropriate Reference Standard in the Standard preparation;Vis the volume,in mL,of Liquid Preparation taken for the Test preparation;and rUand rSare the peak responses of the appropriate analyte obtained from the Test preparationand the Standard preparation,respectively:not more than 0.05%each of sorbitol and sucrose is found.

Mobile phase— Use filtered and degassed water.

Standard preparation— Dissolve accurately weighed quantities of USP Dextrose RSand USP Fructose RSin water to obtain a solution having known concentrations of about 6.0and 2.0mg per mL,respectively.

Test preparation— Transfer about 1.0g of sodium carboxylate cation-exchange resin,accurately weighed,to a 50-mLbeaker,add 5mLof water to make a slurry,and transfer the slurry to a polypropylene automatic pipet fitted with a small plug of silanized glass wool.Quantitatively transfer the slurry to a small chromatographic tube,rinsing the beaker with water and packing the column evenly.Keep the column wet until ready for use.Using a volumetric pipet,transfer 1.0mLof Liquid Preparation to the column,collect the eluate,and discard it.Pipet 4.0mLof water onto the top of the column,collect the eluate in a clean vial,and filter if necessary.

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a refractive index detector and a 7.8-mm ×30-cm analytical column that contains packing L19and is fitted with a guard column that contains packing L19.The analytical column temperature is maintained at 85,and the flow rate is about 0.6mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the relative retention times are about 0.8for dextrose and 1.0for fructose;the resolution,R,between the dextrose and fructose peaks is not less than 1.8;and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— [NOTE—Use peak areas where peak responses are indicated.]Separately inject equal volumes (about 20µL)of the Standard preparationand the Test preparationinto the chromatograph,record the chromatograms,and measure the areas of all the peaks.Calculate the percentages of dextrose and fructose in the volume of Liquid Preparation taken by the formula: in which Cis the concentration,in mg per mL,of the appropriate Reference Standard in the Standard preparation;Vis the volume,in mL,of Liquid Preparation taken for the Test preparation;and rUand rSare the peak responses of the appropriate analyte obtained from the Test preparationand the Standard preparation,respectively:not less than 2.4%dextrose and not less than 0.7%of fructose are found.

Mobile phase— Transfer about 27.2g of monobasic potassium phosphate,accurately weighed,to a 1000-mLvolumetric flask,and dissolve in 950mLof water.Adjust with phosphoric acid to a pHof 2.4,dilute with water to volume,mix,and filter.

Standard preparation— Dissolve accurately weighed quantities of USP Citric Acid RS,USP Malic Acid RS,and USP Quinic Acid RSin water to obtain a solution having known concentrations of about 1.0mg of each Reference Standard per mL.

Test preparation— Use the filtered Liquid Preparation.

Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 214-nm detector and a 4.6-mm ×15-cm analytical column containing packing L1and is fitted with a guard column containing packing L1.The flow rate is about 0.8mLper minute.Prior to use,condition the column with methanol,with water,and finally with Mobile phase.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the relative retention times are about 0.4for quinic acid,0.5for malic acid,and 1.0for citric acid;the resolution,R,between the quinic acid and malic acid peaks is not less than 7.0;and the relative standard deviation for replicate injections is not more than 2.0%.

Procedure— Separately inject equal volumes (about 20µL)of the Standard preparationand the Test preparationinto the chromatograph,record the chromatograms,and measure the areas of the peaks.Calculate the percentages of quinic acid,malic acid,and citric acid in the Liquid Preparation by the formula: in which Cis the concentration,in mg per mL,of the appropriate USP Reference Standard in the Standard preparation;and rUand rSare the peak responses of the appropriate analyte obtained from the Test preparationand the Standard preparation,respectively:not less than 0.9%each of quinic acid and citric acid and not less than 0.7%of malic acid are found,and the ratio of quinic acid to malic acid is not less than 1.0.