JOURNAL O F CHEMICAL EDUCATION
FLUORESCENT LIGHTING AS AN ANALYTICAL HAZARD JOHN A. BISHOP Newark College of Engineering, Newark,New Jersey
A P P R ~ X I ~ . \two ~ ~ Eyr;m I . Y ;tgo rhv 0111 ir)cun~lrwmr lichtittg systems itt the chemical 1al)orntorirsnr S r w r k College of Engineering vere replaced by new and bright daylight fluorescent lighting, so arranged that the working space of all students, even those in the back corners, is completely illuminated. In the analytical laboratory this removed the "classical" student alibi that he could not see the end point properly, but introduced a new and unexpected error. The new fluorescent lights decomposed AgCl precipitates with production of the well-known purple color. It also developed that this is a definite hazard for students in the Mohr's and Fajan's titrations for chloride, since the student has a tendency to titrate more slowly than is necessary. As a result, the end point, particularly in the Fajan's method, is obscured since its detection depends upon the adsorption of the indicator on AgCI. The silver produced by photochemical reduction presents an unsatisfactory sur-
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