The water quality monitoring of used EDTA complexometric titration method. Due to various complex, can form itself can be so many metal titration. Elements of the list, ? ? cycle, lanthanum), actinides metal with EDTA titrimetric. But the most commonly used is used to determine the basicity water.
With magnesium ions examples below Magnesium detection can use EDTA titrimetric method analysis. Because than aluminium magnesium alloy light, so it can be used in aviation, spaceflight. Another using magnesium oxide, to the nature can be used in the manufacture of many of pure metal reductant. Can also be used to flash, inspiratory, etc.
Determination of total hardness is water in calcium, magnesium ions, the total content available EDTA coordination titration: Before the titration, EBT + M - EBT (red), The reaction: M + Y wish End: M - EBT EBT + + Y wish (red) (blue) Titration to solution from red to blue, namely to finish. Titration, Fe3 Al3 + +, such interference ion can be masking triethanolamine, Pb2 Cu2 +, Zn2 + +, weight of ion, usable KCN, Na2S mercaptoacetic acid or to cover. Water hardness has a variety of methods, this experiment requirement to each liter Ca2 +, contained in Mg2 + amount (convert CaO said, the quality of mg, L - 1 unit. Equipment and drugs 1 scales (0.1 g, equipment, RongLiangPing 0.1 mg) (100 ml), 20mL), acid pipette (DiDingGuan type 50mL (250mL), cone-shaped bottle (etc). 2 HC1 drugs (1:1) and ethylenediamine tetraacetate (2), 2H2O A.R., Na2H2Y, alkali type magnesium carbonate [Mg (OH) 2 · · 6H2O, 4MgCO3 benchmark reagent], NH3 - NH4Cl buffer solution (pH = 10.0), (1:1) triethanolamine, chromium black T indicator (0.2% of ammonia solution) etc.
A Mg2 + standard solution, the compound (mol 0.02 L - 1), Accurately weigh alkali type magnesium carbonate benchmark reagent 0.2 ~ 0.25 g, under 100 ml beaker, use a small amount of water, cover, slowly add melamine surface HC1 1:1 to its dissolution (3 ~ 4mL). Add a few water it will be diluted, quantitatively transferred to RongLiangPing 100 ml, diluted to scale, shake. The concentration of computation.
Second, EDTA standard solution preparation and calibration 1 EDTA standard solution preparation (mol 0.02 L - 1), Weigh 2.0 g ethylenediamine tetraacetate (2), 2H2O Na2H2Y 250mL distilled water bottles, turn to preserve polyethylene. 2 calibration standard solution concentration of EDTA Remove Mg2 20mL use pipette + standard solution to join in the bottle, 250mL cone 10mL ammonia sex buffers and 3 ~ 4 drops, EBT indicator, L - 1EDTA mol 0.02 standard solution to the solution of amaranth, titration end to blue namely. Parallel calibration 3 times. EDTA concentration calculated and determined, three times the average.
Third, the total water hardness testing Use 20mL water to remove pipette, 250mL tapered bottle of ammonia 6mL buffer solution, 1:1 3mL solution, EBT indicator of triethanolamine, 3 ~ 4 drops by EDTA titrimetric standard solution to the solution of purple, blue is ending. Become Parallel determination 3 times.