Which of the following is NOT typically used as a humectant in embalming fluids?

Sodium citrate is primarily known for its role as an anticoagulant rather than a humectant. In the context of embalming fluids, humectants are substances that help retain moisture and prevent dryness of the tissues. Glycerin, sorbitol, and propylene glycol are all commonly used in embalming formulations specifically for their properties to maintain moisture in the embalmed remains, thus enhancing the overall preservation process.

Glycerin is well-regarded for its ability to draw moisture into tissues. Sorbitol functions similarly, helping to keep tissues hydrated and pliable, while propylene glycol is effective in preventing dehydration of body tissues post-embalming. These characteristics make glycerin, sorbitol, and propylene glycol suitable choices for inclusion in embalming fluids.

In contrast, sodium citrate's primary function of acting as an anticoagulant is crucial in preventing blood coagulation during the embalming process, but it does not serve the role of a humectant. Thus, identifying sodium citrate as the substance not typically used as a humectant in embalming fluids is accurate given the specific functions each of these compounds has within the embalming process.