# Recent Advances in Sample Preparation for Cosmetics and Personal Care Products Analysis
## 2 Sample Preparation Strategies for Cosmetics Analysis
### Matrix Solid-Phase Dispersion (MSPD)  
In comparison with other extraction techniques that use high pressure such as PLE, or the application of supplementary energy such as UAE, MSPD extraction is performed under ambient conditions, without requiring any special equipment. In addition, the possibility of performing extraction and an in situ clean up would reduce the sample preparation time and decrease the required amount of solvent [88]. MSPD was introduced in 1989 by [PERSON] et al. for the determination of drug residues in animal tissue [89]. Since then, it has attracted growing interest for its versatility and possibility of application to a broad range of solid, semisolid, or viscous matrices. The general procedure consists of the direct mechanical blending of the sample (with a dispersant agent) in a mortar until an homogeneous and dispersed material is obtained, that is then transferred to a cartridge and compressed. Analytes' elution is performed by passing through the column the correspondent solvent by gravity or vacuum assisted. MSPD's first application to cosmetics samples was in 2011 to determine fragrance allergens and multiclass preservatives (parabens, bromine derivatives and antioxidants) in rinse-off and leave-on cosmetics [62; 63] as well as in baby care products [61] before GC-MS analysis. The most critical experimental parameters such as dispersant, elution solvent and volume were optimized by DoE (design of experiments) to obtain the highest extraction efficiency. In all cases, the experimental conditions involved the use of 0.5 g of the sample, 2 g of Florisil(r) as dispersant agent, and elution was accomplished with 5 mL of hexane/acetone (1:1, \(v/v\)). For preservatives' determination, the MSPD-obtained extracts were derivatized by employing anhydride acetic to improve the chromatographic analysis of those containing hydroxyl groups such as parabens. The acetylation procedure was also optimized to obtain a quantitative reaction yield in a short amount of time (10 min) [63]. Another family of preservatives, isothiazolionnes, were also successfully extracted from cosmetic matrices by MSPD. In this case, methanol resulted as the optimal elution solvent, and LC-MS/MS analysis was performed [64]. In all cases, quantitative recoveries and LODs at the low ng g\({}^{-1}\) were obtained, which were well below the legal requirements for those restricted compounds [2]. In order to reduce the sample and solvent consumption, a miniaturization of the classical MSPD, \(\upmu\)-MSPD, was proposed by [PERSON] et al. for the first time in 2013 for the simultaneous analysis of plasticizers (phthalates and adjpates) and synthetic musks in cosmetics and personal care products [65]. Figure 2 schematically represents the \(\upmu\)-MSPD procedure. \(\mu\)-MSPD was subsequently successfully applied for the determination of other cosmetic ingredients including dyes, fragrances, preservatives [66; 67; 68; 69; 70; 71], as well as for the multianalyte determination of a high number of allowed and restricted ingredients, in addition to banned compounds such as glucocorticoids [72; 73; 75]. Recently, this miniaturized approach was also applied to extract impurities or unexpected compounds such as polycyclic aromatic hydrocarbons (PAHs), fungicides, nitrosamines, or alkylphenol ethoxylates (APEOs) from cosmetics formulations. In this case, analysis was performed by GC-MS or LC-MS/MS, depending on the chemical properties of the target analytes. In general, obtained LODs were at the very low ng g\({}^{-1}\) concentration levels, showing that the combination of \(\mu\)-MSPD with chromatography and mass spectrometry detection is a suitable option to determine the trace levels of impurities and banned compounds with a different chemical nature [74]. It is important to highlight that the use of the \(\mu\)-MSPD approach allows a reduction in the extraction costs, since it employs disposable common laboratory use material such as pipette tips or glass Pasteur pipettes [65; 69; 70; 72; 73; 74].