What Are Detergents and Anionic Surfactants?
Detergents are a class of surface‑active agents, or surfactants, designed to break down oils, soils, and organic residues. Surfactants share a common structure: a water‑loving (hydrophilic) head and a water‑repelling (hydrophobic) tail. When added to water, these molecules form micelles, which surround and lift away dirt from surfaces.
Surfactants are grouped by the electrical charge of their hydrophilic head:
- Anionic surfactants: negatively charged; the most common type used in household and industrial detergents.
- Cationic surfactants: positively charged; often used as disinfectants or fabric softeners.
- Nonionic surfactants: no charge; frequently used in food processing and industrial cleaning.
Among these, anionic surfactants, especially linear alkylbenzene sulfonates (LAS), are the primary focus of detergent monitoring programs because they are widely used and can enter natural waters through runoff, sewer overflows, and improper disposal.
Why Test for Detergents (Anionic Surfactants)?
Monitoring anionic surfactants is essential for environmental protection, regulatory compliance, and quality assurance.
- Stormwater Investigations: Municipalities often test for detergents as part of illicit discharge detection programs to identify contamination from household or commercial sources.
- Environmental Impact: Elevated surfactant levels can harm aquatic organisms, reduce water clarity, and disrupt natural ecosystems.
- Industrial & Pharmaceutical Cleaning Validation: Facilities must verify that equipment is free of detergent residues after cleaning.
- Wastewater Monitoring: Treatment plants track surfactant levels to evaluate influent quality and treatment efficiency.
Testing ensures that detergents are not entering waterways at harmful concentrations and that cleaning processes are properly controlled.
Our Detergents (MBAS) Test Kits
CHEMetrics provides specialized test kits for measuring anionic surfactants using the Methylene Blue Active Substances (MBAS) method a widely recognized technique for quantifying LAS in water.
CHEMets® Visual Detergent Test Kit (K‑9400)
This kit offers a simple, field‑friendly way to measure detergents visually.
- Measurement range: 0–3 ppm LAS
- Produces a blue color proportional to surfactant concentration
- Ideal for stormwater screening, environmental monitoring, and quick field assessments
- Refill pack: R‑9400
The CHEMets® kit is listed in the EPA Illicit Discharge Detection and Elimination (IDDE) Manual, underscoring its reliability for field investigations.
Instrumental MBAS Test Kit (I‑2017)
For users requiring higher precision, CHEMetrics offers an instrumental kit paired with a Single‑Analyte Photometer (SAM).
- Measurement range: 0–2.50 ppm LAS
- Provides digital, highly repeatable results
- Suitable for laboratories, industrial facilities, and QA/QC programs
- Refill pack: R‑9423
This method enhances sensitivity and reduces subjectivity compared to visual color matching.
Browse Our Kits
All CHEMetrics detergent and surfactant test kits, along with a full range of water‑quality testing supplies, are available through the AquaPhoenix Scientific eStore.