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Analytical chemistry

1896 Journal of the Chemical Society Abstracts  
A n a l y t i c a1 C h e m i s t rg. New Method of Quantitative Spectrum Analysis. By -According to Lambert-, i f a ray of monochromatic light is passed through a. layer of thickness m, and its luminosity is reduced l / n t h by a layer of unit thickness, the original luminosity J becomes J' = J / n t n , Assuming that the reduction in iunxinosity is the same for a layer of solution of thickness m and concentration c as for a layer of thickness c and concentration m, and t,hat the luminosity is
more » ... t the luminosity is reduced l/YLth by ~t layer of thickness 1 and coiicsntration 1, then J' = J/nme. Placing ?Z?'~C = x we get log x = mc log n, or if x = 10, a condition that can be realised by so arranging the experiment that the luminosity of the light used is reduced to 1110th of its original valuc by absorption in the solution, G E E H A R D K R~S S and H. KRGss (Zeit. niiorg. Chenz., 1895, 10, 31-43). 1 c = -, m log ?L It is evident that n is a constant for one and the same substance, and represents what may be termed the specific absorptive power of that substance. The constant k may be taken to represent the qnnutity l / l o g 12, and, therefore, c = k/m. If k has been determined by observation with a solution of known concentration, it will only be necessary to determine the thickness of the layer, m, of a similar solution oE unknown concentration, required to reduce the luminosity to l/lOth of its original value, in order to find, c, the concentration. The authors describe a new spectrocolorimeter with the aid of which a comparison of solutions of dift'erent concentration can be effected. Estimation of Nitrogen in Peruvian Guano. By HEIBER (Landu;. Verszichs-Stat., 1895, 46,407-408) .--The nitrogen in several silmples of guano was determiued by the Jodlbauer method, and by the washing out process. The guano was mixed with 2 parts cf gjpsum, and the acid (containing 40 grams of phenol per libre) added gradually, keeping well cooled ; zinc dust was gradually added in si~isll quantities. Loss of nitric oxide and of nitrophenol waa thus
doi:10.1039/ca8967005215 fatcat:7szkkpctkjgujhdayzb4bzqtzi