Determination of polyaminopropyl biguanide in cosmetics by high performance liquid chromatography / 上海预防医学

Objective:To establish a high performance liquid chromatographic（HPLC） quantitative method for the determination of polyaminopropyl biguanide（PAPB） in cosmetics. Methods:Different forms of cosmetic samples were prepared by ultrasonic extraction and followed by high speed centrifugation of the extraction solution. The supernatant was degreased by hexane， and then was filtered by 0.22 μm millipore filter. The continued filtrate was taken for analysis. An Agilent reversed phase column， Zorbax SB-C18（5 μm，4.6 mm×250 mm）was used with 0.02 mol/L ammonium acetate buffer （pH=4.8） ： methanol （60∶40） as the mobile phase under the condition of isocratic elution. Diode array detection method was used for PAPB determination. Qualitative and quantitative determination of PAPB was conducted in 51 batches of commercially available cosmetics. Results:The relative standard deviations （RSD） were in the range of 1.2 %-4.4 %（n=6）； the recoveries were in the range of 97.5 %-106.5 %.The method showed a good linearity within the concentration range of 5-1 000 μg/mL with correlation coefficient of 0.999 62； The detection limit was 15 mg/kg. In 51 batches of commercially available cosmetics. One batch of makeup remover showed positive resullt， which was consistent with the UV spectrum of the standard. Conclusion:We have established a HPLC method for accurate quantification of PAPB. It can be used for analyzing the cosmetics products.

Simultaneous determination of 15 mycotoxins in peanuts by ultra high performance liquid chromatography-tandem mass spectrometry with QuEChERS EMR-Lipid approach and stable isotope dilution / 上海预防医学

Objective To develop a method for the simultaneous determination of 15mycotoxins in peanuts by ultra high performance liquid chromatography-tandem mass spectrometry with QuEChERS EMR-Lipid approach and stable isotope dilution. Methods The samples were extracted by 2% formic acid acetonitrile-water (50 : 50, V/V) and then purified with QuEChERS EMR-Lipid approach.The mycotoxins were fully separated on a pentafluorophenyl column under a gradient elution with methonal-0.01%formic acid aqueous solution.The mycotoxins were analyzed by UPLC-MS/MS with multiple reaction monitoring (MRM) mode and quantified by isotope internal standard method. Results Fifteen mycotoxins had good linear relationship in the certain correlation ranges with the correlation coefficients all above 0.995 and the detection limits were 0.1－10 μg/kg.The mean recoveries ranged from 81.2% to 115.3% with RSD (n=6) varying from 2.1% to 10.7%. Conclusion The method is simple, highly sensitive, practical, and proves to be suitable for quantitative analysis of 15 mycotoxins in peanuts.

Rapid identification of two new isomers in bear bile powder by LC-Q-TOF-MS combined with PCC oxidation / 中国中药杂志

A rapid method of Liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) combined with pyridinium chlorochromate (PCC) oxidation has been developed to determine chemical structures of two novel isomers in bear bile powder. Derivatives of ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) were semi-synthesized by PCC oxidation, then were analyzed by LC-Q-TOF-MS. Separation was carried out on a reverse column with the mobile phase of acetonitrile-0.1% formic acid (45:55). The data of Q-TOF-MS was acquired by MS, MS/MS, positive and negative modes. Since UDCA and CDCA were stereochemical isomeric at an alcohol position, two oxidation products were same and have been confirmed by LC-Q-TOF-MS. Other two products were also determined based on the PCC oxidation theory. Samples of bear bile powder were dissolved by methanol and measured by LC-Q-TOF-MS. Two unknown peaks were found and identified by matching their retention times and accurate mass spectra ions with PCC oxidation productS. Finally, the structures of two new bile acids in bear bile powder were confirmed as 3alpha-hydroxy-7-oxo-5beta-cholanic acid, 7alpha-hydroxy-3-oxo-5beta-cholanic acid, respectively.

Structure determination of three novel bile acids from bear bile powder / 药学学报

A method of LC-QTOF/MS combining with chemical synthesis has been used to determine the structures of three novel bile acids from bear bile powder. Reference substances of tauroursodeoxycholic acid and taurochenodeoxycholic acid were oxidized by pyridinium chlorochromate. The products were analyzed by LC-QTOF/MS. Total 4 products including 3 isomers were predicted and identified according to the PCC oxidation theory and LC-QTOF/MS results. Bear bile powder samples were dissolved by methanol and analyzed by LC-QTOF/MS. Three unknown peaks were found and identified as 2-[[(3beta, 5beta)-3-hydroxy-7, 24-dioxocholan-24-yl]amino]-ethanesulfonic acid, 2-[[(5beta)-3, 7, 24-trioxocholan-24-yl]amino]-ethanesulfonic acid and 2-[[(5beta, 7beta)-7-hydroxy-3, 24-dioxocholan-24-yl]amino]-ethanesulfonic acid, separately, by matching their results with that of oxidation products above.