A:Infrared Absorption á197Kñ.

B: Asolution (1in 100)responds to the tests for Chloride á191ñ.

Test solution: 50mg per mL,in water.

Standard preparations— Dissolve an accurately weighed quantity of USP Phenylephrine Hydrochloride RSin methanol to obtain a solution having a known concentration of 1mg per mL.Quantitatively dilute with methanol to obtain Standard preparationshaving the following compositions:

Test preparation— Dissolve an accurately weighed quantity of Phenylephrine Hydrochloride in methanol to obtain a solution containing 50mg per mL.

Procedure— Apply separately 5µLof the Test preparationand 5µLof each Standard preparationto a suitable thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel mixture.Position the plate in a chromatographic chamber and develop the chromatograms in a solvent system consisting of a mixture of n-butyl alcohol,water,and formic acid (7:2:1)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the developing chamber,mark the solvent front,and allow the solvent to evaporate in warm,circulating air.Examine the plate under short-wavelength UVlight.Then spray the plate with a saturated solution of p-nitrobenzenediazonium tetrafluoroborate followed by sodium carbonate solution (1in 10).Compare the intensities of any secondary spots observed in the chromatogram of the Test preparationwith those of the principal spots in the chromatograms of the Standard preparations:the sum of the intensities of secondary spots obtained from the Test preparationcorresponds to not more than 1.0%of related compounds,with no single impurity corresponding to more than 0.5%.