ビンドシェドラーズグリーンロイコ塩基を用いるフローインジェクション分析法による過酸化水素の吸光光度定量

ビンドシェドラーズグリーンロイコ塩基(LBG)を色原体とし,Fe(II)を触媒としたFIA系による過酸化水素の定量法について検討した.弱酸性溶液中,Fe(II)が存在するとLBGは過酸化水素によって725nmに吸収極大を持つ緑色のビンドシェドラーズグリーン(BG(+))に酸化され,この波長での吸光度の増加を利用して過酸化水素を定量した.pH及び共存させる塩酸ヒドロキシルアミンの濃度を調節することにより,過酸化水素が0~1ppmの範囲で検量線は直線性を示す.過酸化水素0.58ppmでの10回繰り返し測定の相対標準偏差は0.4%で,検出限界は5ppb(S/N=2)であった.1時間当たりの分析速度は30検体であった.市販の各種水あめ中のグルコース(3~96%)を,グルコースオキシターゼで反応させた後,FIAで測定した.

A FIA method for the determination of hydrogen peroxide with a Bindschedler's Green leuco base (LBG) as color reagent and iron(II) as catalyst is described. LBG was oxidized by hydrogen peroxide to Bindschedler's Green (BG(+)) which showed a maximum absorbance at 725 nm. The increase in the absorbance at 725 nm was measured for the determination of hydrogen peroxide. The reagent solution (1) consisted of 10 mM hydrochloric acid containing 1 mM LBG, and the reagent solution (2) consisted of 0.1 M acetate buffer (pH 4.6) containing 50 mM ammonium iron(II) sulfate and 0.65 M hydroxylamine hydrochloride. Reagent solutions (1) and (2), and a carrier solution (deionized water) were propelled by two double plunger pumps (flow rate: 0.8 ml/min), and a sample solution (50 μl) was injected into the carrier stream. After mixing the reagent solution (1) and (2) in the preheating coil, the mixture stream was mixed with the carrier stream in the reaction coil (37℃). The linear relationship between the peak height and the concentration of hydrogen peroxide was obtained in the range of 0 to 1 ppm. The relative standard deviation of 0.58 ppm hydrogen peroxide was 0.4% (n=10). The detection limit was 5 ppb (S/N=2). The sampling rate was 30 samples per hour. The glucose in the range of 0 to 10 ppm was determined by the FIA method after the reaction with glucose oxidase.