In cosmetic testing, preservatives are a common test item. In the cosmetic hygiene and safety specifications, some preservatives are also suitable. Here Xiaobian also said more, those cosmetics with their own brand "zero addition of preservatives", more than nine times out of ten are exaggerated publicity, especially the products advertised by "natural formulas", in fact, more effective antiseptic measures are needed. Cosmetics are mostly a variety of animal and plant extracts, oils, water quality, functional additives, the protein, vitamins inside are easily affected by bacteria or microorganisms, especially in the process of use, contact with air or fingers, it is inevitable to bring bacteria or microorganisms, a long time, deterioration, mold, long bacteria are very likely. Therefore, cosmetics want to "zero add preservatives", which is basically unrealistic.
Of course, it is not impossible for cosmetics not to add preservatives. Some disposable cosmetics, cosmetics with extremely small capacity and a very short shelf life can be used without the addition of preservatives. In addition, dry powder, pure oils and fats, cosmetics with high alcohol content and high polyol content may also not need to add preservatives. There is also a tip here, if you want to extend the shelf life of cosmetics, you can avoid direct sunlight, or put the cosmetics in the refrigerator for a while. In fact, we really don't have to mind too much about the fact that cosmetics contain preservatives, the state has clear requirements for the permitted use limits of preservatives, as long as it is a regular manufacturer's product, the concentration of preservatives is generally within the safe range.
It can be said that preservatives are substances used to prevent the growth of bacteria and microorganisms in cosmetics. Cosmetics that want to be protected from microbial contamination, prevent consumers from being infected by it, ensure product safety, and extend shelf life need to add a certain amount of preservatives. If cosmetics do not add preservatives, the product is likely to have precipitation, turbidity, color changes, etc., and some products will have changes in pH value, demulsification, agglomeration, foaming, flavor change, mold points and other quality problems. Therefore, the mechanism of action of preservatives is to inhibit the survival or reproduction of microorganisms and ensure the safety of cosmetics during the storage period and use period.
So having said all this, how does the state regulate the issue of preservatives in cosmetics? According to the provisions of the 2015 edition of the "Cosmetic Safety Technical Specifications", there are 51 items of cosmetics quasi-preservatives, including the Chinese and English names and inci (international cosmetic raw materials) names of each permitted preservative, the maximum allowable concentration, the allowable scope of use and restrictions, the conditions of use and precautions that must be marked on the label. Due to space limitations, we will not explain them all. Here we focus on introducing for everyone, which types of cosmetics should focus on which preservatives? There is also the question of choosing what method to detect.
Detection of methylisothiazolinone preservatives
Water agents, creams, lotions, gels, oils, powders and wax-based cosmetics can detect methylisothiazolinone preservatives. Methylisothiazolinone preservatives can be determined by high performance liquid chromatography . Methylisothiazolinone preservatives can mainly detect 23 components, namely methylisothiazolinone, 2-bromo-2-nitropropane-1,3 diol, 4-hydroxybenzoic acid, methylchloroisothiazolinone, benzyl alcohol, phenoxyethanol, benzoic acid, methyl 4-hydroxybenzoate, chlorphenesin, dehydroacetic acid, 5-bromo-5-nitro-1,3-dioxane, ethyl 4-hydroxybenzoate, 4-hydroxybenzoate*, propyl 4-hydroxybenzoate, 4-hydroxybenzoate*, 4-hydroxybenzoate*, 4- Isobutyl hydroxybenzoate*, butyl 4-hydroxybenzoate, benzyl 4-hydroxybenzoate*, ethyl benzoate, amyl 4-hydroxybenzoate*, isopropyl benzoate, propyl benzoate, and phenyl benzoate.
Zinc pyrothionein testing
Zinc pyrothium preservatives are the same as methylisothiazolinone preservatives and cosmetics are suitable for the same types and detection methods. However, there are 19 detection components of zinc pyrothione preservatives, namely zinc pyrothione, salicylic acid, sorbic acid, phenoxyisopropanol, 2,6-dichlorobenzyl alcohol*, methyl benzoate, iodopropynyl butylcarbamate, p-chloromethylenephenol, 2,4-dichlorobenzyl alcohol, o-phenylphenol, o-umbilberry hydrocarbon-5-ol, chlorodimethylphenol, chlorimidazole, benzyl chlorophenol, piroctone ethanolamine salt, trichlorocarban, triclosan, bromoclofen, and sodium thiomersal.
Hexamidine bis (isethionic acid) salt preservative detection
The types of cosmetics and detection methods of hexamidine-di (isethionic acid) salt preservatives are also the same as the above two preservatives. There are 7 kinds of detection components, including hexamidine bis (isethionylsulfonic acid) salt, chlorhexidine, dodecyltrimethylammonium bromide, dodecyldimethylbenzylammonium chloride, benzylsonium chloride, tetradecyldimethylbenzyl ammonium chloride, cetyldimethylbenzylammonium chloride.
Polyurethyl biguanide preservative detection
The detection method of polyurethyl biguanide is mainly extracted by mixing solvents, separating it by high performance liquid chromatograph, and finally detected by diode array tube detector, where time and UV light spectrum are retained, peak area is quantitative, and finally its content is calculated by standard curve method. The type of cosmetics applied and the testing method are consistent with the above preservatives.
Hexetidine preservative testing
The detection method of hexetidine, first of all, is extracted with methanol as a solvent, and the following steps are basically the same as the detection method of polyurethyl biguanide. It is first separated by a high performance liquid chromatograph, then detected by a diode array detector, the retention time and UV light spectrum are qualitative, the peak area is quantified, and finally the content is calculated by the standard curve method. The type of cosmetics applied and the testing method are consistent with the above preservatives.
Detection of phenylmercury borate preservatives
The extraction method of phenylmercury borate is to use methanol as a solvent for extraction. Other steps and applicable cosmetic grade testing methods are consistent with the above.
Testing of formic acid preservatives
There are 9 types of detection components of formic acid preservatives in cosmetics, including formic acid, propionic acid, trichloro-tert-butanol, isobutyl benzoate, butyl benzoate, undecylenate, 7-ethylbicyclooxazoleline, dimethyloxazolidin, and glutaraldehyde. The applicable cosmetics of formic acid preservatives are water agents, creams, lotions, gels and oils. The detection method can be determined by gas chromatography.
Formaldehyde detection
There are two methods for detecting formaldehyde, namely acetylacetone spectrophotometry and high performance liquid chromatography. Acetylacetone spectrophotometry can detect the total formaldehyde content in cosmetics, but it is not suitable for the determination of formaldehyde content in nail polish containing toluene sulfonamide resin. High performance liquid chromatography is suitable for the detection of formaldehyde in most cosmetics, and can mainly be determined by pre-column derivatization liquid chromatography-ultraviolet detector method.
Free formaldehyde detection
The detection method of free formaldehyde can be determined by post-column derivation-high performance liquid chromatography. Applicable cosmetics mainly include water agents, cream emulsions, gel cosmetics.
The above are the common cosmetic antiseptic testing methods and scope of application. What we need to pay attention to here is that due to the development of testing and inspection technology, many of the preservative detection methods specified in the 2015 edition of the Cosmetic Safety Technical Specification have been abolished. At present, the abandoned preservative detection methods include benzyl alcohol, benzoic acid and its sodium salt, phenoxyisopropanol, benzalkonium chloride, Laura ammonium chloride, benzopyrium chloride and citamidonium chloride, methylchloroisothiazolinone and other 12 components, chlorphenesin, trichlorocarban, sorbic acid and dehydroacetic acid, salicylic acid and other 5 components. You need to know this.