| At present,there are many cases of illegal addition of antibiotics in anti-acne cosmetics.It will cause serious consequences if consumers use such cosmetics in the long term without knowing it.The Safety and Technical Standards for Cosmetics stipulates that antibiotics are banned substances in cosmetics,and has three detection methods for 26 kinds of antibiotics.However,these antibiotics are detected separately by three high performance liquid chromatography and mass spectrometry methods.The whole analysis time is long with multiple steps,causing low efficiency in analysis.In addition,some unscrupulous manufacturers use the current regulatory loopholes to illegally add antibiotics which are lack of standard detection methods to cosmetics.Based on the above situation,it is necessary to expand the detection ranges of target compounds,and further improve the screening and confirmation method for antibiotics illegally added to anti-acne cosmetics.In this study,high performance liquid chromatography coupled with mass spectrometry with high separation efficiency,high sensitivity and high specificity was chosen for research.The main contents were as follows:1.A method was developed for the simultaneous determination of 35 kinds of antibiotics in cosmetics by high performance liquid chromatography-tandem triple quadrupole mass spectrometry(HPLC-MS/MS).Samples including lotion,emulsion,cream and powder were ultrasonically extracted for 10 min at a frequency of 37 kHz by a mixed solution(40%acetonitrile and 60%5 mmol/L ammonium formate containing 0.2%formic acid solution),and then centrifuged and filtered.Separation was conducted on a Waters ACQUITY UPLC BEH C18 reversed phase analytical column(50×2.1 mm,1.7?m)with gradient elution of 5 mmol/L ammonium formate containing 0.2%formic acid solution and acetonitrile at a flow rate of 0.3 ml/min.The analysis was carried out under the positive and negative mode using an electrospray ionization and was done in multiple reaction monitoring mode(MRM),then using product ion mode for further conformation of positive samples.After examining the matrix effect,matrix-matched standard curves were constructed.The method validation showed good linearity in the range of 0.49-1518.21 ng/mL with coefficients of determination(r~2)higher than 0.99 for all 35 components.The limits of detection were in the range of 0.1-380 ng/g.In the recovery experiment,three concentration levels were established,and four categories of samples including lotion,emulsion,cream and powder were spiked.The recoveries ranged from 71.0%to 128.2%,and the relative standard deviations were from 0.1%to 11.9%.The precision was good,and the relative standard deviation was less than 10.1%.After detecting two hundred batches of cosmetics which claimed to have the effect of acne-removing,two batches were detected as positive samples,and the substances were metronidazole,lincomycin,clindamycin and tinidazole.The method has simple sample pretreatment,short analysis time,high specificity and high sensitivity,and could be applied to simultaneously determine 35 kinds of antibiotics illegally added to cosmetics.2.A method for comprehensive screening of 35 kinds of antibiotics in cosmetics was established using high performance liquid chromatography coupled with linear ion trap quadrupole Orbitrap high resolution mass spectrometry(HPLC-LTQ-Orbitrap MS).The analysis was carried out under the data-dependent scan mode,and the positive and negative ions were scanned separately.A small mass spectrometry database was established based on the retention time of the standard,the exact mass of the parent ion and product ions,and the isotope peak information.It could detect 35kinds of antibiotics illegally added to cosmetics without the need for reference substances by using the built database in the subsequent experiments.By analyzing and generalizing cracking pattern of the same class of antibiotics,it could help to analyze the unknown illegal additives. |
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