Yoshimi Hashimoto

Advanced microcolumn techniques in liquid chromatography : Use of glass-lined stainless-steel tubing columns

Abstract Micro packed columns made of glass-lined stainless-steel tubing were prepared and their chromatographic performance was examined. The use of glass-lined stainless-steel tubing of 1 16 in. O.D. facilitated operation under high pressures. The system using such columns was applicable to chromatography with carbon dioxide as the mobile phase.

Ion chromatography on anion exchangers modified with mucopolysaccharides

Anion exchangers modified with mucopolysaccharides, such as chondroitin sulfates and heparin, were used for the stationary phase in ion chromatography. Unusual retention behavior of anions was observed for the modified stationary phases. A 50-microM concentration of tartaric acid could separate inorganic anions in a reasonable time. The retention of analytes could be changed by changing the eluent composition.

Application of micro high-performance liquid chromatography to the separation of chiral amino acids

Abstract Micro high-performance liquid chromatographic separation of dansyl- d,l -amino acids was examined using copper (II)- l -histidine or copper (II)- l -histidine methyl ester as eluent. Parameters that affect the retention and the resolution of dansyl- d,l -amino acids were examined. Gradient elution was used to separate many pairs of amino acids in a single chromatographic run.

Effect of eluent composition on retention behavior of anions in ion chromatography on anion-exchangers modified with heparin

Effect of eluent composition on retention behavior of inorganic anions have been investigated in ion chromatography using anion-exchangers modified with heparin. Both cation and anion of the eluent affected the retention of analyte anions and unusual retention behavior was observed on the modified stationary phase. The retention time of anions decreased with decreasing eluent concentration when sodium sulfate, magnesium sulfate and chlorides of alkali metals were used as the eluent, whereas it increased with decreasing eluent concentration when aluminum sulfate, copper sulfate and sulfuric acid were used as the eluent. The retention of nitrate increased in the order of Li+, Na+, K+, Rb+ and Cs+ when their chlorides were used as the eluent. When sodium perchlorate and chlorides of alkaline-earth metals were used as the eluent, the eluent should include heparin. Otherwise, the modifier was partially bled from the column.

Ion chromatography using anion-exchangers modified with dextran sulfate

SummaryRetention behavior of anions and cations on anion-exchangers modified with dextran sulfate has been investigated. Retention of anions was remarkably reduced by the modification, and the retention factor decreased with decreasing eluent concentration when sodium sulfate was used as the eluent. Cations were also retained on the modified stationary phase, and alkali and alkaline-earth metal ions were separated using copper sulfate or tris(2,2′-bipyridyl)ruthenium chloride as eluent. The size of the dextran sulfate strongly affected the retention behavior of analyte ions.

Microcolumn liquid chromatography by using carbon dioxide as the mobile phase.

二酸化炭素を液体または超臨界流体グロマトグラフィーの移動相として用いるのに簡便なシステムを組み立てた。混合槽を用いることによって, 1台のポンプを使用し, 有機溶媒で改質した二酸化炭素を移動相として用いることができた。分離は二酸化炭素の臨界温度以下で行なった。すなわち, 液体クロvトグラフィー挙動を検討した。シリカゲルおよびODSカラムを用いたとき, 移動相中のメタノールの濃度が増加すると溶質の保持時間は減少する傾向にあった。保持時間の再現性は, 相対標準偏差で5～8%であった。光学活性な固定相を用いる鏡像体の分離にこのシステムを応用したところ良好な結果が得られた。