| 摘要 |
The semiquantitative microtechnique for the calculation of the fluoride ion in potable water results from the Megregian-Maier standard method. The microtechnique is cost effective, easily applied and transported to the field. Te present invention comprises seven parts: test tubes (12x75 mm), caps, two drip containers for the R1 and R2 reactants, a test tube rack with a tilted mirror and a colorimetric scale pattern ranging from about 0.5 mg/L to about 2.5 mg/L of fluoride. The microtechnique presents two optional microscales: a microscale ranging from about 1% to about 4% and a microscale ranging from about 2% to about 5%. The process includes four steps: Step 1) adding 4 ml of the sample water into a test tube in duplicate; step 2) adding five drops (0.5 ml) of the reactant R1 (Alizarin red); step 3a) adding five drop (0.25 ml) of the reactant R2 (acid zirconium solution); step 3b) covering the tubes and stirring the same; step 4) waiting a period of time of 15 minutes and uncovering the tubes, then comparing the colour developed at the bottom of the tube against natural light using the colorimetric scale pattern and qualifying the corresponding fluoride concentration. Said pattern is manufactured by computer using a Macromedia Free Hand MX software, a HP colour laser printer and opaline paper, with the keys 24000 CMYK Combinations.
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