Ensuring a Water Supply for Atomic Absorption, Emission and Plasma Spectrophotometers Our laboratory analyzes approximately 30,000 soil, water and plant samples per year for a variety of nutrients. Metal concentrations are determined using atomic absorption spectmphotometers and a n inductively coupled plasma spectrophotometer The latter operates in tandem with a linear geometry autosampler. One of the problems associated with the icplautosampler combination has been the requirement for constant supervision of the instrument when running large batches of samples. Our autosampler's capacity is up to 540 tubes, and we always wash through the nebulizer assembly between samples to avoid cross contamination, Since the installation of a simple piece of equipment, supervision has been significantly reduced. Other readen of the Journal might find our suggestion ofuse in the operation oftheir own spectraphatometer. 1. Drill a small hole in the lower end of a plastic tube. Insert a suitable tight fitting connector (the barbed variety is best). A suitable adhesive can be used if required. 2. Drill a small hale in a wide diameter plastic container, OUTLET/ and insert another small connector. TUBE 3. Attach a length of small bore polymer tubing ta the two connectors. 4. If racks are used, cut a slit down the side of one or more of the holes. This rdlows easy insertion and removal c the tubds). 5. Fill the reservoir(s1 with water or other solution, and adjust the height, so that the liquid level in the tube does not overflow.
The high volume of the reservoids) will ensure that the tube(s) remains filled with liquid far a significant period of time, and is an interesting reminder that water always finds its own level. For those without autasamplers, a similar arrangement can still be of use, since an obstructing large capacity beaker is eliminated. Michael N. Quigley and W. Shaw Reid Department of Soil, Crop and Atmospheric Sciences Bradfield Hall Comell Univerdty, Ithaca, NY 14853
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Journal of Chemical Education
