SPECIFIC DETERMINATION OF MERCURY IN URINE.

Owing to the well-known toxic properties of mercury, the determination of the mercury concentration in urine may be of both prophylactic and diagnostic importance in circumstances under which absorption of mercury or mercury compounds may occur. The excretion of mercury in the urine of mercury-exposed human beings varies individually from day to day. Thus, determinations upon several 24-hr urine samples are necessary if the results are to be significant. The author has previously described a method for the determination of mercury in urine (Nielsen Kudsk 1964). In that paper some of the various points of view concerning the significance of knowledge of the urinary excretion of mercury in relation to mercury poisoning were briefly mentioned. A determination of the 24-hr urinary excretion of mercury may arouse suspicion of mercury poisoning or may be helpful in confirming the diagnosis in suspected cases, but is not, in itself, diagnostic. A drawback of the method previously described was that abnormally high concentrations of the iodide ion in the urine (greater than 0.5 mg iodine per 25 ml) caused a great negative error in the determination of the mercury concentration. This is probably common to all methods in which extraction of mercury with dithizone from a strongly acid digest solution is used, 6.g. those described by Gray (1952), Barret (1955), Nobel & Nobel (1958) and Jacobs, Yamaguchi, Goldwater & Gilbert (1960). Iodine may also be a source of error in the flamecombustion method described by Lindstr$m (1959).