Determination of Total Fatty Matter (TFM) in Creams: A Practical Chemist’s Guide

In cosmetic and pharmaceutical creams, the fatty matter phase plays a major role in texture, stability, moisturization, spreadability, and skin feel. Determining the Total Fatty Matter (TFM) is an important quality control test used in creams, lotions, emulsions, and semisolid formulations.

This article explains:

• What TFM means
• International guideline approaches
• The chemistry behind the test
• Laboratory workflow
• Reagent preparation from bottle labels
• Calculations
• Practical hands-on procedure
• Common errors and troubleshooting

What is Total Fatty Matter (TFM)?

Total Fatty Matter refers to the total amount of:

• Oils
• Waxes
• Fatty alcohols
• Fatty acids
• Esters
• Lipophilic emollients

present in a cream formulation.

It is usually expressed as:

Why TFM Testing is Important

TFM affects:

• Moisturizing performance
• Skin occlusivity
• Stability
• Sensory feel
• Regulatory compliance
• Batch consistency

Low TFM may indicate:

• Wrong formulation
• Excess water
• Raw material shortage
• Processing problems

High TFM may indicate:

• Overdosing oils/waxes
• Water evaporation loss
• Emulsion imbalance

International Guidelines and References

Chemists generally follow methods adapted from:

• ISO cosmetic testing methods
• BIS methods
• AOAC extraction principles
• USP/NF semisolid analytical approaches
• Internal validated QC SOPs

Commonly used analytical principles include:

• Solvent extraction
• Acid hydrolysis
• Gravimetric analysis

Chemistry Behind TFM Determination

Creams are mostly emulsions.

They contain:

The main chemistry principle is:

“Like dissolves like.”

Nonpolar fatty materials dissolve in nonpolar solvents such as:

• Petroleum ether
• Hexane
• Diethyl ether

Water-soluble components remain behind.

Sometimes acidification is required to:

• Break the emulsion
• Convert soaps into free fatty acids
• Release bound fatty materials

Common Solvents Used

Basic Principle of the Method

The cream is:

1. Weighed accurately
2. Acidified if needed
3. Extracted with organic solvent
4. Solvent layer separated
5. Solvent evaporated
6. Remaining residue weighed

The residue is considered total fatty matter.

Reminder: In our experience, we see that many chemists face challenges in understanding LOD and LOQ. So you may go through that article also.

Laboratory Apparatus

Glassware

• Beaker
• Separating funnel
• Conical flask
• Measuring cylinder
• Pipette
• Volumetric flask

Instruments

• Analytical balance
• Water bath
• Hot plate
• Oven
• Desiccator

Safety Precautions

Organic solvents are:

• Highly flammable
• Volatile
• Harmful by inhalation

Always use:

• Fume hood
• Gloves
• Goggles
• Explosion-safe heating

Never heat solvents directly on open flame.

Hands-On Practical Method

Example Cream Formula

Suppose a cream contains:

Expected fatty matter ≈ 24%

You may also have interest in exploring more formulations beyond the example cream formula. Explore our formulation category here.

Step 1: Sample Weighing

Weigh accurately:

cream into a beaker.

Step 2: Add Acid

Add:

• 20 mL dilute HCl

Purpose:

• Break emulsion
• Convert soap forms into fatty acids

Heat gently at 60–70°C.

Step 3: Solvent Extraction

Transfer into a separating funnel.

Add:

• 30 mL petroleum ether

Shake carefully.

Allow separation.

The upper organic layer contains fats/oils.

Repeat extraction 3 times.

Step 4: Collect Organic Layer

Combine all organic extracts into a pre-weighed flask.

Example:

• Empty flask weight = 52.214 g

Step 5: Evaporate Solvent

Evaporate solvent using:

• Water bath
• Rotary evaporator

Dry residue in oven at 105°C.

Cool in a desiccator.

Step 6: Final Weighing

Suppose:

• Flask + residue = 53.401 g

Therefore:

$\mathrm{F}\mathrm{a}\mathrm{t}\mathrm{t}\mathrm{y}\mathrm{m}\mathrm{a}\mathrm{t}\mathrm{t}\mathrm{e}\mathrm{r}=53.401-52.214=1.187g$

Final TFM Calculation

Sample weight:

TFM:

$\mathrm{T}\mathrm{F}\mathrm{M}=\frac{1.187}{5.000}\times 100=23.74\mathrm{\%}$

How a Chemist Makes Reagents from Bottle Labels

This is a critical QC skill.

Just a minute before starting the examples, we have an article for you, overviewing the Chemical Analysis and Quality Control in Chemistry.

Example 1: Preparing 0.1 N HCl

Bottle label says:

• HCl = 37%
• Specific gravity = 1.18
• Molecular weight = 36.46

Step 1: Calculate Concentration

Pure HCl per liter:

Molarity:

Since HCl has 1 replaceable H⁺:

Step 2: Use Dilution Formula

To prepare 1 L of 0.1 N HCl:

So:

Take 8.35 mL concentrated HCl and dilute to 1 liter.

Example 2: Preparing 70% Ethanol

Suppose bottle says:

• Ethanol = 99.9%

Need 500 mL of 70%.

Using dilution:

Add water up to 500 mL.

Common Sources of Error

Validation Parameters

According to QC standards, methods should be validated for:

• Accuracy
• Precision
• Repeatability
• Specificity
• Robustness

Advanced Instrumental Approaches

Modern laboratories may also use:

• Soxhlet extraction
• GC-FID
• FTIR
• NMR
• Gravimetric automation

But classical solvent extraction remains widely used because it is:

• Simple
• Cheap
• Reliable

Real Industrial QC Perspective

In industry, chemists usually:

1. Follow SOP exactly
2. Use calibrated balances
3. Maintain extraction time
4. Standardize reagents
5. Run blanks
6. Record all calculations in the worksheet

A QC chemist must understand both:

• Practical handling
• Underlying chemistry

because troubleshooting depends on scientific understanding.

Final Thoughts

Determining Total Fatty Matter in cream is fundamentally a combination of:

• Emulsion chemistry
• Solvent extraction
• Acid-base chemistry
• Gravimetric analysis

A skilled chemist does not only follow SOPs mechanically. They understand:

• Why acid breaks emulsions
• Why nonpolar solvents extract fats
• Why drying is critical
• How concentration calculations are made from reagent bottle labels

This combination of analytical chemistry and practical laboratory execution is what separates a trained formulation or QC chemist from someone who only memorizes procedures.

At the end of the determination of total fatty matter, you may be interested in determining the potency of your cream if it has actives like vitamin C, niacinamide, or something like that. Don't worry, we have a guide on this as well. Access it here: Calculate Potency of Any Solution Using UV Spectrophotometer