We have developed a simple, fast, accurate, and cheap method for the simultaneous determination of total cysteine, homocysteine, glutathione, and N-acetylcysteine in brain homogenates based on the reduction of disulfide bonds by tris(2-carboxyethyl) phosphine, pre-column derivatization of free thiol groups with 2-chloro-1-methylquinolinium tetrafluoroborate followed by ion-pair reversed-phase high-performance liquid chromatography separation with ultraviolet detection. The separation of thiol derivatives was achieved in 10 min. Linearity was observed in the range of 10-300, 0.7-10, 2-30, and 3-20 μmol/L homogenate with a limit of detection of 3.7, 0.2, 0.8, and 1.2 μmol/L homogenate for cysteine, homocysteine, glutathione, and N-acetylcysteine, respectively. The precision, calculated as relative standard deviation, was in the range of 1.21-4.77, 1.53-14.35, 0.47-1.92, and 1.61-8.95% for cysteine, homocysteine, glutathione, and N-acetylcysteine, respectively. The presented method was successfully applied to the selective determination of total amino thiols in pig brain tissue samples.

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α-Lipoic acid, glutathione, cysteine, and cysteinylglycine can be applied as therapeutic agents in civilization diseases such as diabetes mellitus, cardiovascular diseases, and cancers. On the other hand, a higher concentration of homocysteine can result in health problems and has been indicated as an independent risk factor for cardiovascular disease and accelerated atherosclerosis. Here, the first simplified HPLC-UV assay that enables simultaneous determination of α-lipoic acid and low-molecular-mass thiols in plasma, reduces the number of steps, shortens the total time of sample preparation, and limits the amount of single-use polypropylene laboratory materials is described. The assay is based on reversed-phase high performance liquid chromatography with UV detection and simultaneous reduction of disulfide bound with tris(2-carboxyethyl)phosphine and the selective pre-column derivatization of the thiol group with 1-benzyl-2-chloropyridinium bromide. Linearity in the detector responses for plasma samples were observed in ranges: 0.12–5.0 nmol mL−1 for α-lipoic acid; 2.0–20.0 nmol mL−1 for glutathione, cysteinylglycine, and homocysteine; and 40.0–400.0 for cysteine. The LODs for α-lipoic acid and low-molecular-mass thiols were 0.08 and 0.12 nmol mL−1, respectively, while LOQs were 0.12 and 0.16 nmol mL−1, respectively. The usefulness of the proposed method has been proven by its application to real samples.

To help to clarify therapeutic functions of lipoic acid (LA) in biochemical and clinical practice we have elaborated a fast, simple and accurate HPLC method enabling determination of LA in human urine. The proposed analytical approach includes reduction of LA with tris(2‐carboxyethyl)phosphine and simultaneous separation and derivatization of the analyte with butylamine and o‐phthaldialdehyde followed by spectrofluorimetric detection at λex = 340 nm and λem = 440 nm. The assay was performed using gradient elution and the mobile phase containing 0.0025 mol L−1 o‐phthaldialdehyde in 0.0025 mol L−1 NaOH and acetonitrile. Linearity of the detector response for LA was observed in the range of 0.3–8 μmol L−1. Limits of detection and quantification for LA in urine samples were 0.02 and 0.03 μmol L−1, respectively. The total analysis time, including sample work‐up, was <20 min. The analytical procedure was successfully applied to analysis of real urine samples delivered from six healthy volunteers who received a single 100 mg dose of LA.

The aim of this study was to develop a multifunctional biomedical coating that is highly corrosion resistant, biocompatible, and reveals the bioactive properties. For that purpose, titanium dioxide coatings doubly-doped with Ca and Ag ions were deposited by dip-coating onto M30NW biomedical steel. The influence of different ratios of Ca and Ag dopants on morphology, surface structure, corrosion resistance, bioactivity, wettability, and biological properties of TiO2-based sol-gel coatings was studied and discussed. Comprehensive measurements were performed including atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray reflectivity (XRR), corrosion tests, immersion test, contact angle, as well as biological evaluation. The obtained results confirmed that anatase-based coatings containing Ca and Ag ions, independently of their molar ratio in the coating, are anticorrosive, hydrophilic, and bioactive. The results of the biological evaluation indicated that investigated coatings are biocompatible and do not reduce the proliferation ability of the osteoblasts cells.