Selective determination of uric acid in the presence of ascorbic acid using a penicillamine self-assembled gold electrode

The electrochemical behaviors of uric acid (UA) at the penicillamine (Pen) self-assembled monolayers modified gold electrode (Pen/Au) have been studied. The Pen/Au electrode is demonstrated to promote the electrochemical response of UA by cyclic voltammetry (CV). The diffusion coefficient D of UA is 6.97 × 10⁻⁶ cm² s⁻¹. In differential pulse voltammetric (DPV) measurements, the Pen/Au electrode can separate the UA and ascorbic acid (AA) oxidation potentials by about 120 mV and can be used for the selective determination of UA in the presence of AA. The detection limit was 1 × 10⁻⁶ mol L⁻¹. The modified electrode shows excellent sensitivity, good selectivity and antifouling properties.     

Penicillamin-Komplexe des Nickels,Chroms und Molybdäns — Strukturelle Besonderheiten und biologische/medizinische Relevanz

Penicillamine Complexes of Nickel, Chromium, and Molybdenum — Structural Particularity and Biological/Medical Relevance The compounds Tl₂[Ni^II(H₂O)₆][Ni^II(D-pen)(L-pen)]₂[Ni^II(SCN)₂(H₂O)₄] 1 , Tl[Ni^II(D-pen)₂H] · H₂O 2 , Tl[Cr^III(D-pen)₂] 3 , and Na₂[MoO₄(pen)₂] · 3 CH₃OH · 3 H₂O 4 have been prepared by the reaction of nickel nitrate (for 1 ), nickel acetate (for 2 ), potassium chromate (for 3 ), and sodium molybdate (for 4 ) with D- and D, L-penicillamine, respectively. They were characterized by single-crystal X-ray structure analysis and other physical methods. Whereas penicillamine acts as a bidentate (N, S)-ligand in 1 and 2 , Cr^III (in 3 ), and Mo^V (in 4 ) are coordinated to the three ligand atoms N, O, and S. The presence of three different types of Ni^II-complexes a cationic, a neutral, and an anionic one in 1 is remarkable. For crystal data see Inhaltsübersicht.     

A simple colorimetric method for the assay of penicillin G salt and penicillamine by oxidation with iodate

A simple colorimetric procedure is described for determination of penicillin G salt and penicillamine. It is based on oxidation with potassium iodate at room temperature and measurement of the liberated iodine at 520 nm after extraction with carbon tetrachloride. Compared with other procedures, this method proved to be more rapid, highly reproducible and reasonably accurate. The relative standard deviation did not exceed 0.9% and 0.4% for penicillin and penicillamine, respectively. The procedure has been successfully applied to pharmaceutical preparations containing either of the two compounds.     

荧光碳点的制备及银离子辅助的点亮型识别青霉胺

以半胱氨酸为原料,通过一步热解法制备了荧光碳点（CDs）,并采用透射电镜（TEM）、动态光散射（DLS）、X射线能谱分析（XPS）、紫外可见吸收光谱（UV-Vis）和荧光光谱（FL）对其进行了表征。结果表明该碳点平均尺寸为3.12 nm,且表现出了良好的荧光特性。银离子能够与碳点结合进而通过光诱导的电子转移有效猝灭碳点的荧光。青霉胺得益于其与重金属离子的配位作用,能够与银离子结合使得后者离开碳点表面从而实现荧光恢复。基于此,我们建立了银离子辅助的碳点荧光点亮型识别青霉胺的新方法。该方法的线性范围为8~500 μmol·L^-1,检出限为5.62 μmol·L^-1。该荧光体系用于尿液样品测定,回收率在97.17%~102.05%范围内。     

Direct enantiomeric TLC resolution of dl-penicillamine using (R)-mandelic acid and l-tartaric acid as chiral impregnating reagents and as chiral mobile phase additive

DL-Penicillamine has been resolved into its enantiomers by normal-phase TLC using L-tartaric acid as chiral impregnating reagent as well as chiral mobile phase additive, while (R)-mandelic acid has been found to be successful as a chiral impregnating reagent. The solvent system acetonitrile-methanol-water (5:1:1, v/v) was found to be successful when L-tartaric acid was used as impregnating agent while the solvent combination acetonitrile-methanol-(0.5% l-tartaric acid in water, pH 5)-glacial acetic acid (7:1:1.1:0.7, v/v) was successful as mobile phase as it contained L-tartaric acid as the chiral additive. (R)-mandelic acid was successful as chiral impregnating reagent with ethyl acetate-methanol-water (3:1:1, v/v), as the mobile phase. The effects of concentration of chiral selectors, temperature and pH were examined on enantiomeric resolution. The spots were detected with iodine vapors and the detection limits were found to be 0.12 microg for each enantiomer of penicillamine with L-tartaric acid, under both the conditions, and 0.11 microg with (R)-mandelic acid.     

青霉胺对映体的毛细管电泳手性分离及应用研究

建立了一种青霉胺对映体的毛细管电泳手性分离方法。采用2,4-二硝基氯苯作为青霉胺的衍生试剂,以磺化-β-环糊精(S-β-CD)作为手性选择剂,50mmol/LpH9.5的硼砂缓冲溶液作为电泳缓冲液,在14min内实现了青霉胺对映体的毛细管电泳手性拆分,分离度达3.7。本文还考察了在大量D-青霉胺存在下,测定微量L-青霉胺的可能性。当D-青霉胺中,L-青霉胺的含量在0.3%~2.0%范围内时,其浓度与吸光度之间呈现良好的线性关系(r=0.9995),对D-青霉胺药片进行光学纯度分析,获得了满意的结果。     

Magnetic d‐penicillamine‐functionalized cellulose as a new heterogeneous support for cobalt(II) in green oxidation of ethylbenzene to acetophenone

A new efficient heterogeneous catalyst is introduced for the oxidation of ethylbenzene. The catalyst was obtained in three steps: functionalization of cellulose with d ‐penicillamine, deposition of Fe₃O₄ nanoparticles on cellulose–d ‐penicillamine and then anchoring of Co(II) to the magnetic cellulose–d ‐penicillamine. High yield and excellent selectivity were achieved for the oxidation of ethylbenzene to acetophenone in ethanol under reflux conditions using H₂O₂ as a green oxidant. Also, the recovered catalyst could be applied six times without a decrease in activity.