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Propolis is rich in flavonoids and phenolic acids, which has strong antioxidant capacity. Two methodologies for simultaneous determination of 20 phenolic compounds in propolis by HPLC-UV and HPLC-MS/MS were developed. The sample extraction and chromatographic separation conditions, and ultraviolet detection wavelength, as well as mass spectrometry parameters were selected and optimized. Under the optimized conditions, good linearities (R 2 ≥0.998) were obtained for all analytes. The limits of quantification (LOQs) of the proposed methods by HPLC-UV and HPLC-MS/MS for all analytes were in the range of 0.02–0.1 mg/g and 0.05–0.2 mg/g, respectively, and the recoveries were in the range of 95.4 %− 109.5 % and 94.0 %− 106.8 % with the relative standard deviations (RSDs) in the range of 1.1 %− 7.5 % and 0.4 %− 11.1 %, respectively. The proposed methods were applied for the determination of 20 phenolic compounds in 13 propolis samples collected from China and Brazil. The detection results of the two methods are almost consistent with each other, indicating that both methods are applicable, and the inter-confirmation of the two methods can improve the accuracy of the determination of phenolic components in propolis. • HPLC-UV and HPLC-MS/MS methods were established for 20 phenolic compounds determination. • 75 % ethanol was optimized as the best solvent for phenolic compounds extraction. • 13 propolis samples were determined with similar results. • The advantages and disadvantages of the two methods were compared. [ABSTRACT FROM AUTHOR]

Abstract: In recent years, two adulteration incidents concerning the addition of melamine, a small polar compound which is very rich in nitrogen, to pet food and infant formula products have occurred in China. These issues prompted private as well as governmental laboratories to develop methods for the analysis of melamine and related compounds in a wide variety of food products and ingredients. The development of methods was focussed on both, screening and quantification purposes, ranging from highly sophisticated chromatographic-mass spectrometric techniques to immuno-selective assays. The present work describes two screening and two confirmatory methods dedicated to the determination of melamine in cow’s milk and milk-based powdered infant formula. Screening methods are enzyme-linked immunosorbent assay (ELISA) and liquid chromatography coupled to ultraviolet detection, while confirmatory methods are based on gas and liquid chromatography coupled mass spectrometry techniques. Performance and validation data of the four methods, and results obtained in the frame of internal and European proficiency-tests are shown. [ABSTRACT FROM AUTHOR]

[Display omitted] • Low-cost irregular silica without any chemical modification was used as an effective DSPE sorbent. • The interference of oily matrix on detection could be mostly removed after pretreatment with DSPE. • The whole pretreatment method was simple, time-saving and economical. • The proposed method was proved to be reliable for the content control of calcitriol soft capsules. Calcitriol is an active product of vitamin D produced by the liver and kidney hydroxylase metabolism with strong physiological activity. It is the preferred form of medicine for patients with insufficient bone mineralization due to chronic kidney disease. Calcitriol soft capsule is one of the common preparation forms, the main drug content of which is very low (1.55 μg g−1), and the pharmaceutical excipients interfere greatly, especially the oily matrix medium-chain triglycerides. Therefore, removing the interference of oily matrix is ​​the main challenge in the content determination. At present, the commonly used sample purification method for the determination of calcitriol in soft capsules is liquid-liquid extraction, but it usually consumes a lot of toxic organic solvents and it is costly. The adoption of SPE purification method, on the one hand, requires specific experimental equipment, and on the other hand, the organic solvent used in the experiment may cause the dissolution of SPE column tube materials, which will interfere with the subsequent detection. Herein, in order to achieve a cost-effective and reliable determination of calcitriol soft capsule content, we developed a dispersive solid-phase (DSPE) extraction method that directly uses irregular silica as sorbent, which is followed by high-performance liquid chromatography equipped with a UV detector(HPLC-UV)analysis. Selective retention of calcitriol is achieved by the polar interaction between calcitriol and silica, what's more, sufficient contact between washing solvent and sorbent can be guaranteed. Therefore, after pretreatment with DSPE, the interference of oily matrix on detection can be mostly removed and then improve the accuracy of the method compared to the SPE method. Under the optimal conditions of DSPE, calcitriol showed a good linear relationship in the range of 0.15−2.99 μg g−1, the R2 was 0.997. Satisfactory recoveries ranging from 101.1%–102.0% for calcitriol were achieved in the oily matrix at the levels of 0.75, 1.50 and 2.24 μg g−1. And the intra-day and inter-day RSD were less than 2.5 % and 3.2 %. Meanwhile, the LOD and LOQ of calcitriol was 0.01 μg g−1 and 0.02 μg g−1, which is in full compliance with the regulatory level fixed by the EU, China or other countries. This method was further verified to determine the content of calcitriol in commercial calcitriol soft capsules and the recoveries of three batches of products was 86.2 %–94.4 %. Based on these characteristics, the proposed method makes it possible to determine the low content of weakly polar drugs in the oily matrix in a simple, low-cost and reliable way. [ABSTRACT FROM AUTHOR]

Coptis plants (Ranunculaceae) to have played an important role in the prevention and treatment human diseases in Chinese history. In this study, a multi-level strategy based on metabolic and molecular genetic methods was performed for the characterization of four Coptis herbs (C. chinensis, C. deltoidea, C. omeiensis and C. teeta) using high performance liquid chromatography-ultraviolet (HPLC-UV) and restriction site-associated DNA sequencing (RAD-seq) techniques. Protoberberine alkaloids including berberine, palmatine, coptisine, epiberberine, columbamine, jatrorrhizine, magnoflorine and groenlandicine in rhizomes were identified and determined based on the HPLC-UV method. Among them, berberine was demonstrated as the most abundant compound in these plants. RAD-seq was applied to discover single nucleotide polymorphisms (SNPs) data. A total of 44,747,016 reads were generated and 2,443,407 SNPs were identified in regarding to four plants. Additionally, with respect to complicated metabolic and SNP data, multivariable statistical methods of principal component analysis (PCA) and hierarchical cluster analysis (HCA) were successively applied to interpret the structure characteristics. The metabolic variation and genetic relationship among different Coptis plants were successfully illustrated based on data visualization. Summarily, this comprehensive strategy has been proven as a reliable and effective approach to characterize Coptis plants, which can provide additional information for their quality assessment. [ABSTRACT FROM AUTHOR]