Product Overview

Barium Diphenylamine Sulphonate AR (CAS No. 6211-24-1) is the barium salt of diphenylamine-4-sulphonic acid, a sulphonated diarylamine compound used as an oxidation–reduction indicator. Its diphenylamine-derived conjugated system undergoes oxidation to a strongly coloured form when the solution potential passes through its indicator-transition region. The para-sulphonate functionality provides an ionisable derivative that is more suitable than unsubstituted diphenylamine for preparing indicator solutions used in aqueous analytical media.

The AR grade is intended for redox-indicator solution preparation, conventional oxidimetric titrations, and analytical quality-control procedures requiring a sensitive visual endpoint. It is particularly appropriate for acidic titrations involving potassium dichromate and iron(II), where the reduced indicator is weakly coloured and the first slight excess of oxidant produces a distinct violet to red-violet endpoint response.

Typical Applications

• Internal redox indicator in the titration of iron(II) with standard potassium dichromate.
• Determination of total iron in suitably prepared ores, rocks, slags, and other inorganic samples following reduction to iron(II).
• Endpoint detection in the standardisation and verification of dichromate and ferrous reagent solutions.
• Indicator in selected uranium determinations completed by iron(II) reduction and dichromate titration.
• Endpoint adjustment in established volumetric methods for vanadium and ferrovanadium analysis.
• Preparation of analytical indicator solutions for conventional oxidation–reduction titrations conducted in acidic media.

Common Synonyms

• Barium Diphenylamine Sulfonate
• Barium Diphenylamine-4-sulphonate
• Barium Diphenylamine-4-sulfonate
• Diphenylamine-4-sulphonic Acid Barium Salt
• Diphenylamine-4-sulfonic Acid Barium Salt
• 4-(Phenylamino)benzenesulphonic Acid Barium Salt
• 4-(Phenylamino)benzenesulfonic Acid Barium Salt
• N-Phenylsulphanilic Acid Barium Salt
• Barium Diphenylamine p-Sulphonate

Storage Conditions

Store in a tightly closed container in a cool, dry, and well-ventilated area. Protect from humidity, direct light, excessive heat, and contamination, particularly contact with oxidising materials that could affect the reagent’s indicator response. Close the container promptly after use to preserve analytical sensitivity and solution performance.