LAB NOTES & SAFETY NOTICE
These are personal experiments for educational use only— not instructions and not for commercial or consumer use. By proceeding, you assume all risks related to safety, testing, and regulatory compliance.
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Lab Notes: The ASM Reality
After spending so much time with surfactants, it’s clear that formulating a detergent isn’t about the volume of the bottle, but about the ASM (Active Surfactant Matter). It’s a core lesson: since raw surfactants are usually sold as solutions (mostly water), the only way to know the real “cleaning power” is to calculate the active part of the molecule.
What I’ve Learnt About ASM Targets
The ASM Protocol — Quantitative Detergent Design
In surfactant chemistry, we do not formulate based on the “volume of the bottle” but on the Active Surfactant Matter (ASM). Since raw surfactants are sold as aqueous solutions (e.g., 30% active matter and 70% water), we must calculate the true concentration of the “cleaning” part of the molecule to ensure safety and efficacy.
1. The ASM Target Reference
Before calculating, I define the target ASM based on the physiological needs of the area being cleansed. High ASM provides more “bubbles” and stripping power, while low ASM preserves the lipid barrier.
| Product Type | Target ASM Range | Formulation Goal |
| Face / Intimate Wash | < 10% | Ultra-delicate; avoids stripping the acid mantle. |
| Shampoo | 10% – 15% | High wetting ability; removes sebum/styling products. |
| Shower Gel | 15% – 20% | Standard body cleansing; good foam volume. |
| Bubble Bath | 20% – 25%+ | Maximum foam stability; not intended for direct skin contact. |
2. The Mathematical Approach: Solving for ASM
I utilize two primary methods in the lab to reach my target (e.g., a 18% ASM Shower Gel).
Method A: Quota Division (Precise)
I decide exactly what “share” each surfactant contributes to the total 18% and solve for the grams needed.
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Sarcosinate (29% ASM): Quota 10% then I calculate: 10 / 0.29 = 34.48g
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Betaine (36% ASM): Quota 5% so: 5 / 0.36 = 13.88g
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Lauryl Glucoside (52% ASM): Quota 3% so: 3 / 0.52 = 5.76g
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Total ASM = 18%
Method B: Gram Estimation (Iterative)
I estimate the grams first and check the result against the target.
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40g { Sarcosinate}* 0.29 = 11.6g
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15g { Betaine} * 0.36 = 5.4g
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5g { Lauryl Glucoside} * 0.52 = 2.6
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Total ASM = 19.6% (Adjust grams downward to reach 18%).
3. Raw Material Profiles & Behavioral Notes
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Sodium Lauroyl Sarcosinate (Anionic – 29%): Eco-friendly and creamy. Viscosity is highly dependent on a pH of 5.0. It is sensitive to oils and fragrances, often requiring Xanthan Gum for stabilization.
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Cocamidopropyl Betaine (Amphoteric – 30-38%): The “Buffer.” When paired with Anionics (like SLES), it creates a salt-thickening curve. It significantly reduces the irritation potential of harsher surfactants.
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Lauryl Glucoside (Non-Ionic – 52%): A thick, cloudy paste. Excellent for thickening and skin-mildness, but requires gentle heating ($40^\circ\text{C}$–$50^\circ\text{C}$) to become workable.
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Disodium Cocoamphodiacetate (Amphoteric – 38%): The “Baby” surfactant. Does not trigger the ocular sting reflex; ideal for “no-tears” formulations.
Researcher Summary
Calculating ASM is the only way to ensure reproducibility in the lab. By mastering this math, I can hopefully swap one surfactant for another (e.g., replacing SLES with a more eco-friendly Sarcosinate) while maintaining the exact same “strength” of the detergent.







