February 10, 2018
Weigh a single capillary tube on the pan of a four-place balance (or preferably on a microbalance). Immerse in water a few millimeters to draw a small amount of water into the tube. Carefully wipe off the outside of the tube, replace on the balance pan and re-weigh. Determine amount of water by difference. Place tube in an aluminum or glass sample boat. Insert boat into vaporizer tube, cap oven, push boat to oven entrance, where it will stop. Press START; the PURGE cycle will begin. When the PURGE cycle is over, the display will show ADD SAMPLE. Press START immediately. The test will continue automatically until you are prompted for mass weight, etc. PROCEDURE & TEMPERATURE: At the temperature of the intended analysis, typically 150ºC to 300ºC. Higher temperatures give shorter analysis time. Time will be longer in glass boats than in aluminum boats. • Purge (min) 1 • Preheat 0 • Cool Time 0 When display reads ADD SAMPLE, press START immediately. CAPILLARY TUBES • Clinical type, untreated (no heparine or EDTA). • Melting Point Tubes May have to be broken into smaller pieces (discard sealed end). • Micro-Pipettes Any size-40 microliters satisfactory. Tubes should be capable of containing 1 to 10 milligrams of water. This quantity of water should result in 1000 to 10,000 micrograms on the display. A deviation of ± 5% is considered satisfactory. This is the same deviation we allow for direct injection of water into the titration vessel for quality control procedures.