Quantification of oligopeptide-20 and oligopeptide-24 in cosmetic creams using hydrophilic interaction liquid chromatography with electrospray ionization mass spectrometry

Peptides are a very popular category of cosmetic ingredients covering a wide range of applications in cosmetics. Hydrophilic interaction liquid chromatography is promising for the analysis and separation of such polar substances. In this work, the chromatographic behaviour of oligopeptide-20 and oligopeptide-24 was initially investigated on a zwitterionic ZIC (R)-HILIC analytical column under isocratic elution with UV detection. Then, a hydrophilic interaction liquid chromatography with positive ion electrospray mass spectrometric assay was developed and validated for the quantitation of these peptides in cosmetic creams. All analytes were separated by using a polymeric zwitterionic ZIC (R)-pHILIC analytical column (150.0 x 2.1 mm i.d., particle size 3.5 mu m, 200 angstrom) with isocratic elution. The mobile phase was composed of a 28% 32.5 mM ammonium formate water solution pH 9.5 in acetonitrile and pumped at a flow rate of 0.25 mL min(-1). A run time of less than 11 min for each sample made it possible to analyze a large number of samples per day. This is the first reported application of hydrophilic interaction liquid chromatography in the simultaneous determination of oligopeptide-20 and oligopeptide-24 in cosmetic creams and it can be used to support routine quality control of these products

Quantification of three beta-lactam antibiotics in breast milk and human plasma by hydrophilic interaction liquid chromatography/positive-ion electrospray ionization mass spectrometry

The use of cephalosporins during breast feeding raises several issues, including the risk of drug exposure through breast milk for the infant. In this paper, a hydrophilic interaction liquid chromatography/positive ion electrospray mass spectrometric assay (HILIC/ESI-MS) was developed for the quantitation of cefuroxime, cefoxitin, and cefazolin in breast milk and human plasma. The assay was based on the use of small sample size, 25 μL of biological samples, following acetonitrile precipitation of proteins and filtration that enabled injection into the HILIC/ESI-MS system. All analytes and the internal standard, alfuzosin, were separated by using a ZIC®-HILIC analytical column (150.0 × 2.1 mm i.d., particle size 3.5 µm, 200 Å) with isocratic elution. The mobile phase was composed of a 6% 12.5 mM ammonium acetate water solution in acetonitrile and pumped at a flow rate of 0.25 mL min-1. The assay was linear over a concentration range of 0.2 to 5 µg mL-1 and 0.4 to 20 µg mL-1 for all the analytes in breast milk and in human plasma, respectively. Intermediate precision was found to be less than 4.2% over the tested concentration ranges. A run time of less than 12 min for each sample made it possible to analyze a large number of biological samples per day. The method is the first reported application of HILIC in the analysis of antibiotics in breast milk and human plasma and it can be used to support a wide range of clinical studies. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd