Development and validation of a simultaneous analytical method for non-steroidal therapeutic compounds in cosmetics using liquid chromatography-tandem mass spectrometry.

Atopic dermatitis is a typical chronic inflammatory skin disease that affects all age groups and requires basic skin care for treatment. Anti-inflammatory and antiallergy steroids are the most frequently used treatments but they are limited due to their side effects caused by a weakening of the immune system. Many consumers focus on performance as a criterion for selecting cosmetics. However, steroids have been illegally used to improve the performance of cosmetics, and consumers have been adversely affected by the corresponding side effects. In this paper, we propose a simple and rapid method using liquid chromatography-tandem mass spectrometry to simultaneously analyze ten non-permitted atopic therapeutic compounds in cosmetic products: chlorpheniramine maleate, ketotifen fumarate, doxepin hydrochloride, azelastine hydrochloride, bufexamac, clotrimazole, tranilast, fusidic acid, tacrolimus, and pimecrolimus. Additionally, the major characteristic fragment ions for tacrolimus, pimecrolimus, and clotrimazole were identified by time-of-flight mass spectrometry. The specificity, linearity, limit of detection, limit of quantification, recovery, precision, accuracy, and stability of the proposed method were validated. The limit of detection and quantification were in the ranges of 5.05-203.30 pg/mL and 15.15-609.90 pg/mL, respectively. The proposed analysis method could help improve the safety management of cosmetics.

Characterization of banned colorants in cosmetics: A tandem mass-based molecular networking approach.

Colorants have been a staple in the cosmetics industry for a considerable time, although certain varieties have been banned owing to health risks. Detecting and confirming these banned colorants simultaneously poses several challenges when employing LC-MS/MS. Molecular networking is a promising analytical technology that can be used to predict the structure of components and the correlation between them using structural and MS/MS spectral similarities. Molecular networking entails assessing the number of fragmented ions and the cosine score (the closer it is to one, the higher the similarity). In this study, we developed and verified a method for the simultaneous quantitative analysis of the 26 banned colorants in cosmetics using LC-MS/MS. Additionally, we propose a novel approach that combines LC-Q-TOF-MS and molecular networking technology to detect banned colorants in cosmetics. For successful molecular networking, a minimum of six fragment ions with cosine scores exceeding 0.5 is required. We developed a screening method for characterizing banned colorants using molecular networking based on LC-TOF-MS results for 26 banned colorants. Furthermore, we demonstrated that our established method can be used for screening by analyzing actual cosmetics (eyebrow tattoo, lipstick tattoo, and hair tint) spiked with three non-targeted banned colorants with similar structures (m/z 267.116, 315.149, and 345.157) in cosmetics. The combination of molecular networking techniques and LC-MS/MS proves highly advantageous for the swift characterization and screening of non-targeted colorants in cosmetics.

Retention behavior of microparticles in gravitational field-flow fractionation (GrFFF): effect of ionic strength.

Retention behavior of micron-sized particles in gravitational field-flow fractionation (GrFFF) was studied in this study. Effects of ionic strength and flow rate as well as the viscosity of the GrFFF carrier liquid was investigated on the size-based selectivity (Sd), retention ratio (R), and plate height (H) of micron-sized particles using polystyrene latex beads as model particles. It was found that the retention ratio of microparticles increases with increasing flow rate or the viscosity of the carrier liquid as the particles are forced away from the accumulation wall by increased hydrodynamic lift forces (HLF). On the other hand, the retention time increases (retention ratio decreases) with increasing ionic strength of the carrier liquid at the same flow rate, due to decreased repulsive interaction between the particles and the channel accumulation wall (glass in this study) allowing the particles approach closer to the wall. Results suggest the ionic strength of the carrier liquid plays a critical role in determining retention of microparticles in GrFFF as well as the viscosity or the flow rate of the carrier liquid. It was found that the resolution and the separation time could be improved by increasing the carrier viscosity and by carefully adjusting the ionic strength of the carrier liquid.