Preparing a CMC solution: record purchased powder and dry polymer separately

A CMC solution described as “2%” is incomplete unless its concentration basis is known. Record whether the number refers to purchased powder or a defined dry-polymer equivalent, and whether the denominator is final solution mass.

Start with the test or formulation definition

The OIV CMC monograph, analytical procedures illustrates the need for a defined preparation when characterising the material. Follow the actual agreed method for your grade; this article does not replace it with a new release test.

In a hypothetical example, 20.0 kg of powder contains 95.0% material counted as dry CMC under the agreed definition. If final solution mass is 1,000 kg, the preparation contains 2.00% purchased powder and 1.90% defined dry CMC. It is not 2% dry CMC. The 95% value is invented and is not an ENVO specification.

Avoid a second denominator error

Adding 20 kg powder to 1,000 kg water produces 1,020 kg total before any losses, not 1,000 kg. Define how evaporative or transfer losses are handled and record the actual final mass. Dry-basis corrections must use the specified measurement and composition definition rather than an assumed moisture figure.

Include the preparation basis with any viscosity comparison or ENVO sample enquiry. A controlled mass ledger can explain an apparent concentration difference before the team blames a supplier lot. It does not by itself establish viscosity, complete dissolution or final-product suitability.

Related decisions

• CMC degree of substitution and viscosity: put both in the grade definition
• Food-use or industrial CMC? Match the specification to the intended use

Review Sodium Carboxymethylcellulose (CMC) product identity and purchasing requirements. For the decision above, send ENVO your application, acceptance criteria, quantity and destination. Confirm the offered grade and available documents before ordering.