Spectral absorbance of some aqueous solutions in the range 10-degrees to 40-degrees-C

Abstract

The effect of temperature upon the absorption spectr~ in the ultravio. let an~ part of the visible ranges was determined for several c~mpounds Jl1 aqueo~ls SOlutlOll. 1 e m.p e r~­ tures used were 10 0 , 25 0 , and 40 0 C. The 1l1~ten al s used as solu tes JI1cludedbot h morgalllc and organic compounds, namely, potassium I1ltrate, potassIUm dIChromate, d lpl;enylsulfon e, diphenyl phosphate, 4,4'-diaminobenzophenone! and. m-creso]sulfonphthalem. As the temperature ,yas dec reased there was a n IIlcrease 111 l?aXlmU1l1. absorbance of all compol:llds except i n the case of dip henyl phosphate, the behavlOr of .WhlC!"t was anomalous. A slJght s hift of the absorbance curves also occurred. The relatlOns hlp betwee n absorbance and temperature was not linear in the temperature range i~v es tigated. The results showed that temperature shou ld be controlled within ± 2 deg. C If molar .absorbance values are to .be obtained within 0.5 perce nt. T emperature coeffiClents for an llldlvldua.l compound req uIre extensive absorption m easurements of that compound III k~lown medIa, and such coefficients wi ll hold for the sp ecifi ed wavelengths only under speC Ifi ed condItIOns. As a general guide the temperature shou ld be controlled to ± 0.5 d eg C.