A cleaning technic for mercury in the clinical laboratory.

COMMONLY USED TECHNICS for cleaning mercury in the laboratory are those whereby mercury is washed several times with a variety of solutions (water, sucrose solution, detergents, or diluted nitric acid), followed by filtration through a cheesecloth or pin-holed filter paper. These methods are not only inadequate, but also present a health hazard. The distillation of mercury is not practical in the clinical laboratory. To obviate these problems, a simple and safe method was devised and is presented here. The pooled used mercury is washed with water by stirring with a plastic rod in a plastic beaker. The mercury is rinsed in running tap water and most of the last rinse water is poured off, leaving a sufficient amount to cover the mercury in the container. The whole container is transfered into a freezer (temperature usually -20#{176}) and left overnight. On the following day the frozen upper aqueous layer is lifted off and the cold mercury is poured into a clean container through a cheesecloth filter. Mercury freezes at -38.87#{176}(1). The container is covered with a tight lid and the mercury is warmed to room temperature before use. Reference