PubMed · 9645020
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H Hidaka. 1998. [Sitosterolemia].. https://pubmed.ncbi.nlm.nih.gov/9645020/
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A coupled ion chromatography (IC) system was used for the determination of chloride, sulphate and phosphate in high-purity nitric acid. Such a high ionic strength matrix causes a selectivity problem in single IC systems. The first part of the system is used for a pre-separation of the analytes from the nitrate matrix. A specially designed high-capacity anion exchanger with low retention for the analytes and high retention for nitrate was developed. The eluent stream containing the analytes was transferred to the second part of the system via a heart-cut valve and a pre-concentration column. The second system utilizes a high performance anion exchanger and is used to quantify the analytes. Recoveries of the analytes are 80-100% for phosphate, and around 100% for sulphate and chloride. Detection limits for chloride, sulphate and phosphate in concentrated nitric acid (69% w/w) are 0.1, 1 and 5 mg/l, respectively.
Different chromatographic methods including chromatofocusing are used for separation of manganese peroxidase (MnP) isoforms and their isolation from the fungal growth medium. We tested strong anion exchange methacrylate based monolithic columns as a stationary phase for fast separation of MnP's. Sodium acetate buffers of two different pH values (6 and 4) were used for formation of reproducible pH gradient. The entire cycle, involving analysis and column regeneration, was completed in 3 min. Use of pH gradient showed better MnP isoform separation comparing to the salt gradient, while application of combined pH-salt gradient, resulted in further improvement.
The catalytic activity for the decomposition of hydrogen peroxide by anion-exchangers modified with metal complexes of thiacalix[4]arenetetrasulfonate (Me(n+)-TCAS[4], Me(n+)=Mn(3+), Mn(2+), Fe(3+), Co(3+), Co(2+), Cu(2+), Zn(2+) and Ni(2+)) was investigated. As a reference, calix[4]arenetetrasulfonate, calix[6]arenehexasulfonate and calix[8]areneoctasulfonate were also examined. Mn(3+)- and Fe(3+)-TCAS[4] on the modified anion-exchangers showed high catalytic activity in alkaline buffer solutions among metal complexes tested. Mn(3+)- and Fe(3+)-TCAS[4] on the modified anion-exchangers exhibited high and constant levels of catalytic activity even after having been used 5 times, and showed catalytic activity in the presence of an excess of H(2)O(2) over Mn(3+)- and Fe(3+)-TCAS[4] on the modified anion-exchangers. Only Mn(3+)-TCAS[4] on the modified anion-exchangers exhibited high catalytic activity at around a neutral pH.