Iodoform, chemically known as triiodomethane (CHI3), is a bright yellow crystalline solid formed via the haloform reaction, typically by treating acetone or ethanol with iodine and an alkaline solution. Because it serves pharmaceutical, laboratory, and industrial purposes, suppliers produce it across compendial (USP/NF, BP/DAB), analytical (ACS/Reagent), and technical grades, each reflecting a different context of use.

Grade determines suitability for pharmaceutical and dental formulation work versus laboratory reagent use versus bulk industrial intermediate use. Key selection criteria include purity level, compendial compliance where USP/NF or BP/DAB standards apply, and the intended application, whether that's analytical testing, wound-care formulation, or chemical synthesis.

Common Grades & Purities

Pharmaceutical Grade (USP/NF, BP/DAB)

This grade meets United States Pharmacopeia–National Formulary standards, as well as British Pharmacopoeia and DAB compendial requirements. It has been used in wound dressings, dental root canal pastes, and historical antiseptic formulations such as BIPP (bismuth iodoform paraffin paste), which combines iodoform with bismuth subnitrate and paraffin and saw extensive use in wound packing during and after World War I.

ACS/Reagent Grade

This is the high-purity grade used for laboratory and analytical applications, notably the iodoform test for detecting methyl ketones and oxidizable secondary alcohols. The American Chemical Society has not published a specific monograph for iodoform, so "Reagent" grade denotes the highest commercially available purity per supplier specification rather than a formal ACS standard. Iodoform is light-sensitive and decomposes slowly on exposure to light, so reagent-grade material is typically stored in light-resistant containers to preserve purity.

Industrial/Technical Grade

This is a lower-purity grade used as a chemical intermediate, including as a precursor in producing diiodomethane, also known as methylene iodide, which is used as a heavy medium in gravity separation processes.

Applications Based on Type

Pharmaceutical & Healthcare

USP/NF or BP/DAB grade is the appropriate choice. This grade has been used historically, and in some current applications, in dental and wound-care formulations for its antiseptic and disinfectant properties.

Laboratory & Analytical

ACS/Reagent grade is standard for laboratory and analytical work. It supports the iodoform test and other organic chemistry reactions.

Industrial & Manufacturing

Technical grade is a good fit for bulk industrial use. It serves as a chemical intermediate, including in the synthesis of diiodomethane.

How to Choose the Right Type

Match Grade to Application

Select compendial grade, USP/NF or BP/DAB, for pharmaceutical or dental formulation use. ACS/Reagent grade is the right choice for analytical testing, while technical grade suits bulk industrial intermediate use.

Verify Required Certifications

Confirm compendial compliance documentation, USP/NF or BP/DAB, and cGMP manufacturing status when sourcing for pharmaceutical or dental applications.

Select Appropriate Concentration or Form

Iodoform is supplied as a single crystalline powder form rather than in multiple physical forms. Confirm that supplier packaging, bulk powder versus a compounded product, matches your intended use.

Common Mistakes

Purchasing technical grade for a pharmaceutical or dental application that requires compendial compliance is a frequent error. A second common mistake is assuming ACS grade implies an official ACS monograph exists for iodoform, when in practice "Reagent" grade purity for this compound is supplier-defined. A third is storing reagent-grade material improperly, without light protection, which degrades purity before use.

Key Takeaways

Choosing the right type of iodoform comes down to matching purity and compendial standing to the application at hand. Pharmaceutical and dental buyers need compendial documentation and cGMP assurance, laboratory users need consistent reagent-grade purity for reliable results, and industrial buyers can rely on technical grade for intermediate manufacturing use. Confirming these distinctions before purchase helps avoid compliance gaps and ensures the material performs as expected for its intended purpose.

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