Nowadays, with the improvement of people’s living standards, cosmetics or personal care products have become an integral part of our daily life. However, the allergenic components in cosmetics or personal care products can lead to skin symptoms for many users, such as redness, itching, stinging, peeling, and red spots. Although people are enthusiastic about the cosmetics, people know very little about the irritating allergens which can cause different injuries to the skin. In general, the familiar allergens can be broadly classified into the following categories, such as preservatives, spices, phenylenediamines, microorganisms, and heavy metals. Among them, spices are the most common allergen we’re exposed to, which can cause allergy reactions by direct contact with the skin, breathing in the process of volatilization, or photosensitization. As spices allergens are growing to threaten our health, the European of SCCS (Scientific Committee on Consumer Safety) has ruled that the warning mark must be indicated on the label if the content of 26 spices in non-irrigable cosmetics is greater than or equal to 0.001%, or the content in irrigable cosmetics is greater than or equal to 0.01%2. Besides that, according to reports of the literature3, allergic reactions in the cosmetic are at least 35% caused by the spices. Therefore, here we mainly focus on the detection of spices allergen in the cosmetics.

At present, analytical methods for spices allergens in cosmetics mainly include gas chromatography(GC), gas chromatography-mass spectrometry(GC-MS), liquid chromatography (HPLC), the online thermal desorption gas chromatography-mass spectrometry, gas chromatography-fourier transform infrared spectrum, multi-dimensional gas chromatography and multi-dimensional gas chromatography-mass spectrometry, etc.

GC/GC-MS Analysis
As a common analytical technique, GC has been used in many fields and is especially good at analyzing organic compounds with low boiling point. The advantage of gas chromatography for the detection of spices allergens is that all of spices except two natural extracts (oak and tree moss) are volatile chemicals. Therefore spices can be detected quickly and simply by GC. A method of gas chromatography-triple quadrupole-mass spectrometry (GC-MS/MS) has been developed for the rapid simultaneous determination of 38 cosmetic ingredients, 25 fragrance allergens and 13 preservatives in cosmetics or personal care products by M Celeiro. The results of the method show the satisfactory performance in terms of linearity, sensitivity, accuracy and precision with an average recovery of 90% and an RSD value generally below 10%. In addition, a very low detection limit (low ng / g) can be achieved using GC coupled triple quadrupole mass detection (MS / MS). Most of the target substances were found in the samples at concentration levels from sub parts per million to the parts per mill, and several fragrances and preservatives have been detected at levels above 0.1% (1000 ug/g). Although the detection of allergens has mainly been carried out by GC or GC-MS, many types of aromatic and volatile substances with similar chemical structures in cosmetics can result in more interference from the gas chromatograph, and reduce analysis selectivity and reliability. In a word, we will have to use our own judgment to determine each specific sample.

HPLC / HPLC-MS Analysis
Compared with gas chromatography, the number of peaks in liquid chromatography is less, and the interference between them is weaker, so the separation efficiency is higher. A method of simultaneous determination of 24 allergens in perfume was established with high performance liquid chromatography tandem mass spectrometry by Wang JY. The target compounds were extracted with acetonitrile and determined with HPLC-MS /MS (MRM mode,ESI) with external standard method. The result of good linear relationship between concentration and peak area ratio is obtained in the range of 1.0~5.0 mg /L for the 24 allergens. The average recoveries of 24 allergens are 85.9%~110.0% with relative standard deviations (RSDs) of 5.5%~12.0%. This method is simple, rapid, accurate, easy to operate, and has good repeatability, which can make up for the poor separation and inaccurate quantification by gas chromatography spectrometry. Besides, it can realize the rapid detection of large quantities of samples. Meng XS had successfully determined the coumarin (a kind of the spices) allergen and its seven derivatives in cosmetics by HPLC-MS. The experimental results indicated that good linearities were observed over a certain concentration range with correlation coefficients better than 0.9996. The average recoveries of the three spiked analytes ranged from 84.6% to 100.7%, with a relative standard deviation of 0.8% to 9.7%. This method has advantage of accuracy, robustness and specificity in the detection of coumarin allergens in cosmetics.