Amido black 10 B (redox)
Dissolve 0.2 g dye in 100 ml of water
color change = yellowish-brown to blue Alizarin Dissolve 0.1g. in 100 ml. of 95% ethanol.
pH =10.1 - 12.1; color change = red to purple Alizarin yellow Dissolve 0.1g. in 100 ml. of water.
pH =10.0 - 12.1; color change = light yellow to brownish yellow Alizarin sulphonic acid Na salt Dissolve 0.1g. in 100 ml. water or in 100 ml 1:1 ethanol and water.
pH =4.3 - 6.3; color change = yellow to violet Alkali blue Dissolve 0.1g. in 100 ml. of 95% ethanol.
pH =9.4 - 14.0; color change = violet to pink
Fast Sulphon Black F (metal ion EDTA)
Sodium salt of 1-hydrovy-8-(2-hydroxynaphthylazo)-2-(solphonaphtylazo)-3,6-disulphonic acid (V)
The indicator solution is 0.5% solution in water.
Specific colour change for copper is from magenta to pale blue to bright green. Ferric indicator: (adsorption) Use a saturated Ammonium Ferric sulphate soln. (~ 40%), add a few drops of 6M nitric acid, and use 1 ml for each titration. Ferroin: (redox) Make a 0.025M in water. or Dissolve 0.7g FeSO4.7H2O and 1.5g 1,10 o-phenanthroline in 100 ml water.
color change = blue to orange-red Fluorescein: (adsorption) Dissolve 0.2g in 100 ml 70 % alcohol, or
Dissolve 0.2g of sodium fluorocienate in 100 ml water. HHSNNA (metal-ion EDTA) See Patton and Reeder's Indigo carmine Dissolve 0.25g. in 100 ml. of 50% ethanol, or dissolve 1g in 100ml of water.
pH =11.5 - 13.0; color change = blue to yellow Indigo carmine (Indigo disulfonate disodium salt) (redox) Dissolve 0.5g in 100 ml water
color change = blue to yellowish Litmus Dissolve 4g. in 100 ml. of water.
pH =5.0 - 8.0; color change = red to blue
Note on Litmus:You can purify the commercial litmus as follows: Digest 10g. of the litmus with 35ml.of rectified spirit on a water bath for about 1 hr and decant the alcohol.; repeat this process twice. Extract the residue several times with water and allow to stand for several days. Decant or siphon off the clear extract. This is of suitable concentration for most purposes.
Bromo-cresol purple or Bromo-thymol blue are excellent substitutes for litmus.
Azolitmin is the pure litmus colouring matter. Dissolve 0.1g. in 100ml of water.
Patton and Reeders indicator (metal-ion EDTA)
2-hydroxy-1-(2-hydroxy-4-sulpho-1-naphthylazo)-3-naphthoic acid (111)
Also known by the abbreviated name HHSNNA.
The dyestuff is thoroughly mixed with 100 times its weight of sodium sulphate, and 1g of this mix is used for each titration.
Used in the direct titration of calcium, particularly in the presence of magnesium, pH range 12-14.
A sharp colour change is obtained from wine red to pure blue. Phenolphthalein Dissolve 0.5 g. of the reagent in 50ml.of alcohol and add 50ml of water with stirring. Filter if a precipitate forms or
Dissolve 1g. of the dry indicator in 80 mls.ethylene glycol monoethyl ether (cellosolve) b.p.135oC, and dilute to 100ml. with distilled water.: the loss by evaporation is less by this preparation. Phenol red Dissolve 0.1g. in 100 ml. of 20% ethanol, or dissolve 0.04g in 1.13 ml of 0.1M sodium hydroxide and make up to 100 ml.
pH =6.4 - 8.2; color change = yellow to red-violet Pentamethoxytriphenyl carbinol
Dissolve 0.1 g in 100 ml of 95% ethanol
pH =1.2 - 3.2; color change = red to colorless 1.10-Phenanthroline (monohydrate) (redox) Dissolve 0.695 g of FeSO4
x 7H2O and 1.487 g of 1.10-Phenanthroline in 100 ml of water
color change = pale-blue to red N-Phenylanthranilic acid: (redox) Dissolve 0.1 g in 5 ml of 0.1M sodium hydroxide and make up to 100 ml with water.
color change = purple-red to colorless Picric acid
Dissolve 0.1 g in 100 ml of 20% ethanol
pH =0.2 - 1.0; color change = colorlass to yellow Pyrocatechol Violet
Pyrocatechol sulphone phthalein (VII); Catechol violet. (metal-ion EDTA)
Dissolve 0.1g of the dyestuyy in 100ml.of water. This solution is stable for several weeks.
Colour change is progressive, from yellow yo blue to green.
Dissolve 0.1 g in 100 ml of 60% ethanol
pH =1.4 - 3.2; color change = colorless to pink Rhodamine: (adsorption) Dissolve 0.05 g in 100 ml water. Safranin (redox) Dissolve 0.5g in 100 ml water
color change = blue-violet(acidic),brown (alkaline) to colorless
Universal indicator (Full-range)
Dissolve 0.026g thymol blue, 0.060g mrthyl red, 0.300g bromothymol blue, and 0.500g phenolphthalein in about 500ml ethanol. Add dilute NaOH until solution turns green (neutral), Color changes from strong acid to alkaline: red to yellow to green (neutral) to blue to purple. Variamine Blue B (metal-ion EDTA)
The indicator solution is a 1% solution of the base in water.
Ferric complex with EDTA - sharp change in redox potential - colourless to violet blue complex. Variamine blue salt B (redox) Dissolve 1.0 g in 100 ml
of water or grind with sodium chloride or sodium sulfate anhydrous trituration
color change = blue-violet(acidic),yellow (alkaline) to colorless p-Xylenol blue Dissolve 0.1g. in 100 ml. of 50% ethanol, or dissolve 0.04g in 0.98 ml of 0.1M sodium hydroxide and make up to 100 ml with water.
pH =1.2 - 2.8; color change = red to yellow p-Xylenol blue Dissolve 0.1g. in 100 ml. of 50% ethanol, or dissolve 0.04g in 0.98 ml of 0.1M sodium hydroxide and make up to 100 ml with water.
pH =8.0 - 9.6; color change = yellow to blue Xylenol Orange
Dissolve 0.5g of xylenol orange indicator in 100ml. of water. The solution is stable indeffinitely.
Acid solutions are coloured lemon yellow and those of the metal complexes intensely red.