Skip to Content
Merck
  • Determination of penicillin G in milk samples using its effect on cloud point extraction of triiodide ion.

Determination of penicillin G in milk samples using its effect on cloud point extraction of triiodide ion.

Journal of AOAC International (2014-08-26)
Nahid Pourreza, Mohammad Reza Fat'hi, Ali Hatami
ABSTRACT

A cloud point extraction (CPE) method for determination of trace amounts of penicillin G by spectrophotometry based on its effect on the triiodide ion (I3(-)) has been developed. Penicillin G is converted to the corresponding penicilloic acid by carrying out hydrolysis with sodium hydroxide solution, and treatment with acid yields D-penicillamine that is oxidized quantitatively by iodine to give rise to a disulfide. The 13- remaining in the solution is extracted into the surfactant Triton X-100, and the difference between absorbance of the working solution in the presence and absence of penicillin G is proportional to the amount of penicillin G. The effects of different variables, such as concentrations of sodium hydroxide, hydrochloric acid, surfactant, and I3(-) and the temperature and incubation time on the CPE were studied. The calibration graph was linear in the range of 50-1250 microg/L, and the LOD was 38 microg/L (n = 10). The RSD for 10 replicate determinations of 1000 microg/L of penicillin G was 1.0%. The method was applied to the determination of penicillin G in milk samples.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Penicillin G sodium salt, powder, BioReagent, suitable for cell culture
Sigma-Aldrich
Penicillin G sodium salt, ~1650 U/mg
Sigma-Aldrich
Penicillin G sodium salt, 96.0-102.0%
Supelco
Penicillin G potassium salt, VETRANAL®, analytical standard
Sigma-Aldrich
Penicillin G potassium salt, powder, BioReagent, suitable for cell culture
Sigma-Aldrich
Penicillin G potassium salt, 95.0 - 102.0%
Sigma-Aldrich
Penicillin G potassium salt
Benzylpenicillin potassium, European Pharmacopoeia (EP) Reference Standard
USP
Penicillin G potassium, United States Pharmacopeia (USP) Reference Standard