Snow (cryotolerant) algae often form red (pink) spots in mountain ecosystems on snowfields around the world, but little is known about their physiology and chemical composition. Content and composition of pigments in the cells of the cryotolerant green microalgae Chloromonas reticulata have been studied. Analysis of carotenoids content in the green (vegetative) cells grown under laboratory conditions and in the red resting cells collected from the snow surface in the Subpolar Urals was carried out. Carotenoids such as neoxanthin, violaxanthin, anteraxanthin, zeaxanthin, lutein, and β-carotene were detected. Among the carotenoids, the ketocarotenoid astaxanthin with high biological activity was also found. It was established that cultivation of the algae at low positive temperature (6°C) and moderate illumination (250 μmol quanta/(m2⋅s) contributed to accumulation of all identified carotenoids, including extraplastidic astaxanthin. In addition to the pigments, fatty acids accumulated in the algae cells. The data obtained allow us to consider the studied microalgae as a potentially promising species for production of carotenoids.

Macrocyclic compounds such as crown ethers and cyclodextrins play an important role in the field of chromatography and show excellent separation performance. The design of simple and convenient methods for the efficient synthesis of novel chiral macrocycles for chromatographic separation is of great significance. In this work, a novel chiral polyimine macrocycle (PIMC) was designed and synthesized by the simply one-step reaction of 2,6-diformyl-4-tert-butylphenol with (S)-(-)-1,2-propanediamine. Then, it was bonded onto silica by the thiol-ene click reaction to construct a new chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC). The chiral separation performance of the proposed CSP was examined by separating various racemates in the normal-phase (NP) and reversed-phase (RP) HPLC. In total, twelve and nine racemates, including ethers, esters, amines, alcohols, organic acids, ketones, and epoxides, were separated to varying degrees via NP-HPLC and RP-HPLC, respectively, Moreover, the CSP offered good chiral separation complementarity to Chiralcel OD-H and Chiralpak AD-H columns for resolution of these test racemates, and it can separate several racemic compounds that either cannot be separated or cannot be separated well be separated by the two commercially available columns. After the column was used for hundreds of injections, the relative standard deviations of the retention time and resolution were below 0.56 % and 0.45 %, respectively, showing the good reproducibility and stability of the CSP. This study provides a simple and convenient approach to synthesize a novel chiral macrocycle and CSP and also indicates the broad application prospects of such chiral PIMCs in HPLC chiral separation.

Salvia miltiorrhiza is one of the famous traditional Chinese medicines for treating cardiovascular and cerebrovascular diseases. Tanshinone and phenolic acids are the main active compounds of Salvia miltiorrhiza, whereas the distribution patterns of the two kinds of components are still unclear among Salvia spp. In this work, high-performance liquid chromatography was applied to analyze the distribution patterns of major components in the roots and leaves of 58 Salvia spp. The results showed that the distribution patterns of tanshinone and phenolic acids in Salvia spp. varied significantly. Phenolic acid components such as rosmarinus acid, caffeic acid, and danshensu are widely distributed in the roots and leaves, and phenolic acids in the leaves of Salvia spp. are generally higher than that in roots. Tanshinones are mainly detected in the roots of Salvia przewalskii, Salvia trijuga, Salvia castanea, and Salvia yunnanensis. The content of major components of the different species varied significantly. The content of phenolic acids in most Salvia spp. generally followed the pattern of salvianolic acid B > rosmarinic acid > danshensu > caffeic acid both in the roots and leaves. Tanshinone IIA and cryptotanshinone were the main lipophilic components of Salvia spp. distributed in southwest China. A correlation between the distribution pattern of tanshinone and the genetic relationship of species was indicated in the work. This research systematically reveals the distribution patterns of tanshinone and phenolic acids in Salvia spp., providing a theoretical basis for the development and utilization of medicinal resources of Salvia.

Calcium β‑hydroxy-β-methylbutyrate (CaHMB) can promote muscle growth, prevent muscle atrophy, and enhance immunity, therefore, it is widely used as a nutritional supplement in special medical formula food and sports nutrition food. Many methods for the detection of CaHMB have been reported, but the pretreatment method for these reported literatures directly involves extraction using hydrochloric acid solution, without any purification steps. A method for accurately determining CaHMB in special medical formula food and sports nutrition food was established for the first time using solid-phase extraction (SPE) purification and high-performance liquid chromatography method (HPLC). The samples were extracted and precipitated protein using methanol-water solution, purified using SPE method and analyzed by HPLC on diode array detector (DAD) mode under external standard method. The method obtained excellent calibration linearity (r2>0.9993) and a satisfactory analysis of the targeted compound, which were evaluated with calibration standards over the range of 0.020-2.00 mg/mL. The limit of quantifications (LOQs), which defined as the lowest spiking level, were set at 0.4 g/100 g (special medical formula food) and 1.0 g/100 g (sports nutrition food). The average recoveries were within 92.9-104% for the analytes, and the relative standard deviations (RSDs) were below 3.93%, measured at low, medium, and high concentrations. Moreover, the positive sample analysis results indicated that CaHMB was detected on 10 real special medical formula food and sports nutrition food products, the contents of which were generally consistent with their labeled values, with measured values ranging from 97.1 % to 119 % of the labeled values. These results suggested that the developed highly sensitive and specific method is highly feasible for monitoring of the target analyte in special medical formula food and sports nutrition food.

Formaldehyde is naturally present as a product of common metabolism in a diverse range of foods, including meat, fish, vegetables, and processed foods, and can also be introduced to food unintentionally due to its ubiquity in the environment. There has been increased interest in dietary exposure to formaldehyde because of its adverse health effects via multiple sources. The aim of this study was to evaluate the formaldehyde levels in various agricultural products and conduct a deterministic exposure assessment for the South Korean population. Formaldehyde levels were measured using high-performance liquid chromatography, with the samples extracted using water and then derivatized with 2,4-dinitrophenylhydrazine. The levels of formaldehyde were found to range from 0.006 to 25.6 µg/g in agricultural food products (n = 480). For the deterministic exposure assessment, multiple sources for point estimation were employed, with consumption data taken from the 2017 Korean Nutrition Survey. The mean daily formaldehyde exposure per each person was 127.5 µg for the South Korean, constituting approximately 1.4% of the tolerable daily intake (TDI). The hazard index (the ratio of the entire formaldehyde exposure to the TDI) normally fell within the range from 0.01 to 0.22 based on assumptions employed in the deterministic estimation of dietary intake. Based on these estimates, the exposure of the general South Korean to formaldehyde was considered to be safe.
UNASSIGNED: The online version contains supplementary material available at 10.1007/s10068-024-01547-7.

We describe a nitrogen-specific detector (NSD) for aqueous mobile phase-based high performance liquid chromatography (HPLC). It is based by means of total hydrophilic organic nitrogen detection. Separated analytes are photooxidized online and converted to nitrate, followed by an ultravilet absorbance detector. It features response dependant on the product of nitrogen number in the molecule and its molar concentration, no matter what is ultravilet-absorbing or not. The HPLC equipped with NSD can quantify nitrogen-containing analytes via a sole standard of potassium nitrate for calibration. This results in identical calibration curve for all nitrogen-containing analytes, obviating individual calibration. The limit of detection of NSD is 4.3 μM N/L, and its linear range is up to 4 mM N/L.

A novel magnetic nanomaterial with Fe3O4 as the core, PS-DVB as the shell layer, and the surface modified with C18 (C18-PS-DVB-Fe3O4) had been synthesized by seeded emulsion polymerization. C18-PS-DVB-Fe3O4 retains the advantages of the chemical stability, large porosity, and uniform morphology of organic polymers and has the magnetic properties of Fe3O4. A simple, flexible, and efficient magnetic dispersive solid phase extraction (Mag-dSPE) method for the extraction of preservatives, sweeteners, and colorants in river water was established. C18-PS-DVB-Fe3O4 was used as an adsorbent for Mag-dSPE and was coupled with high-performance liquid chromatography (HPLC) to detect 11 food additives: acesulfame, amaranth, benzoic acid, tartrazine, saccharin sodium, sorbic acid, dehydroacetic acid, sunset yellow, allura red, brilliant blue, and erythrosine. Under the optimum extraction conditions, combined with ChromCoreTMAQC18 (5 μm, 4.6 × 250 mm), 20 mmol/L ammonium acetate aqueous solution and methanol were used as mobile phases, and the detection wavelengths were 240 nm and 410 nm. The limits of detection (LODs) of 11 food additives were 0.6-3.1 μg/L with satisfactory recoveries ranging from 86.53% to 106.32%. And the material could be reused for five cycles without much sacrifice of extraction efficiency. The proposed method has been used to determine food additives in river water samples, and results demonstrate the applicability of the proposed C18-PS-DVB-Fe3O4 Mag-dSPE coupled with the HPLC method to environment monitoring analysis.

A covalent organic framework (COF) was gown on porous silica with 1,3,5-tri(4-aminophenyl)benzene and 2,5-divinyl-1,4-phenyldiformaldehyde as monomers, and two ionic liquids were grafted to COF by a click reaction. The materials before and after the modification of ionic liquids were separately packed into solid-phase extraction columns (10 × 4.6 mm, i.d.), which were coupled with liquid chromatography to construct online analysis systems. The extraction mechanisms of polycyclic aromatic hydrocarbons, bisphenols, diphenylalkanes and benzoic acids were investigated on these materials. There were π-π, hydrogen-bond and electrostatic interactions on ionic liquid-functionalized sorbents. After the comparison among these materials, the best sorbent was used, and the analytical method was established and successfully applied to the detection of some estrogens from actual samples. For the analytical method, the detection limit was as low as 0.005 μg L-1, linear range was as wide as 0.017-10.0 μg L-1, and enrichment ratio was as high as 3635. The recoveries in actual samples were 70 %-129 %.

Hemoglobin (Hb) disorders are among the most prevalent inherited diseases. Despite a limited number of involved genes, these conditions represent a broad clinical and prognostic spectrum. The menu of laboratory tests is extensive. From widely available modalities, for example, complete blood count to rather sophisticated molecular technologies, the investigation of Hb disorders recapitulates an increasing complexity of laboratory workup in other medical fields. This review highlights a current state of biochemical and molecular investigation of Hb disorders and offers a glimpse on technologies that are yet to be fully embraced in clinical practice.

Reduced glutathione (GSH) is an endogenous tripeptide antioxidant which plays a crucial role in a variety of physiological and pathological activities. Although GSH is not present in any FDA-approved drug product, GSH dietary supplement products and compounded GSH drugs are available to patients in the US. Several incidents of toxicity have occurred in recent years due to endotoxin or otherwise contaminated GSH in compounded drugs. Efficient and sensitive analytical methods are needed for assessing and ensuring the quality of GSH substance and associated drug or dietary supplement products. Impurities A (L-cysteinylglycine), B (cysteine), C (oxidized L-glutathione) and D (γ-L-glutamyl-L-cysteine) are the main related impurities for GSH drug substance which have been detected and quantified by capillary electrophoresis and qNMR analytical procedures. However, there are no reported HPLC methods for detecting or quantifying the three main related impurities A, B and D even though numerous HPLC analytical methods have been reported for analyzing GSH and impurity C. In this report, an isocratic HPLC-UV analytical procedure was developed and validated for separating and identifying GSH and related impurities A-D as well as a newly identified degradant, L-pyroglutamic acid (pGlu), within 10 minutes with resolution (RS) more than 3. The LOD and LOQ were determined to be 0.02 % w/w and 0.05 % w/w, respectively, for impurities A-D and pGlu. Importantly, the optimized HPLC analytical procedure for GSH assay does not have interference from impurities A, B and D, providing highly specific results compared to the commonly used iodine titration method. The newly validated analytical procedure was applied to assess different commercial GSH bulk substance samples. The results suggest that the analytical procedure described in this work is suitable for quality assessment of GSH samples.