다중파장 분광광도법 적정을 사용하여 25 oC에서 0.1M NaNO3를 함유한 에탄올-물 이성분 혼합 용매 중에서 네 가지 수용성 비타민인 엽산(비타민 B9 또는 B10), 티아민(비타민 B1), 리보플라빈(비타민 B2) 및 피리독살(비타민 B6)의 양성자이전상수를 조사하였다. 인자분석모형으로 pH-흡광도 데이터를 적절한 질량균형방정식에 곡선맞추기 (curve fitting)하여 양성자이전 평형상수, 스펙트럼, 농도 도표와 성분 수를 계산하였다. DATAN 프로그램으로 산도상수를, SPECFIT 프로그램으로 표준편차와 부분상관계수를 계산하였다. Gran 도시에 바탕을 둔 4-파라미터 식, pH = α + SpcH + JH+[H+] + JOH-Kw/[H+]에 의거한 유리전극 보정과정을 사용하여 pH값을 농도 척도(pcH)로 읽었으며, 용매가 양성자이전상수에 미치는 영향을 고찰하였다.
A multiwavelength spectrophotometric titration method was applied to study protolytic constants of four water-soluble vitamins, folic acid(vitamin B9 or B0), thiamine(vitamin B1), riboflavin(vitamin B2) and pyridoxal (vitamin B6) in binary ethanol-water mixtures at 25oC and an ionic strength of 0.1M NaNO3. The protolytic equilibrium constants, spectral profiles, concentration diagrams and also the number of components has been calculated from the curve fitting of the pH-absorbance data with appropriate mass balance equations by an established factor analysis model. DATAN program was used for determination of acidity constant and SPECFIT program was used for calculation of standard deviations and partial correlation coefficients. A glass electrode calibration procedure based on the four parameter equation pH=α+SpcH+JH+[H+]+ JOH-Kw/[H+] based on the Gran,s plots was used to obtain pH-readings in the concentration scale (pcH). The effect of the solvent on the protolytic constants was discussed.
