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Detergents Test Kits

Visual Kit

Range MDL Method Type Kit Refill
0.0 - 3.0 ppm 0.125 ppm Methylene Blue CHEMets K-9400 R-9400

Instrumental Kits

Range Method Type Kit
0 - 2.50 ppm Methylene Blue Vacu-vials R-9423
0 - 2.50 ppm Methylene Blue SAM Photometer + Vacu-vials I-2017

The CHEMetrics test kits for Detergents (anionic surfactants, MBAS) in aqueous solutions are based on patented Self-Filling Reagent Ampoule technology, and utilise the Methlyene Blue Active Substances (MBAS) method. The procedure features a unique extraction and sampling technique that eliminates several steps required in other test procedures and provides increased sensitivity. Premixed. Premeasured. Precise. Each CHEMets kit contains 30 tests (Vacu-vials contain 20 tests). Suitable for pharmaceutical industry as well as residential water testing.

CHEMetrics is proud to have the CHEMets® detergents test kit listed in the USEPA‚Äôs Illicit Discharge Determination Elimination (IDDE) manual, Appendix F.

CHEMetrics offers a visual (K-9400) CHEMets test kit that can measure detergents visually at a range of 0-3 ppm LAS. The shelf-life of the R-9400 refill is 5 months. If you require more precision we recommend the instrumental (I-2017) kit, which comes with a Single-Analyte Photometer (SAM) that measures at a range of 0-2.50 ppm LAS. The shelf-life of the R-9423 refill is 8 months.

The Methylene Blue Method

The methylene blue active substances (MBAS) method is used in a 3-minute procedure to measure anionic detergents in the 0-3 ppm (mg/l) range. Anionic detergents react with methylene blue to form a blue-coloured complex that is extracted into an immiscible organic solvent. Results are expressed in ppm (mg/l) as linear alkylbenzene sulphonate (LAS), equivalent weight 325.

USEPA Methods for Chemical Analysis of Water and Wastes, Method 425.1 (1983).
APHA Standard Methods, 21st ed., Method 5540 C (2005).
ASTM D 2330-02 , Methylene Blue Active Substances.

Technical Data Sheet


Detergents can be introduced into the water supply by industry, soap manufacturers and private households, which can pollute natural bodies of water. Environmental analysts often include a determination of anionic detergents when assessing surface water pollution. Municipalities often monitor stormwater for detergents as a part of an illicit discharge field investigation program.

Cleaning validation is a requirement in industries such as pharmaceutical manufacturing which adhere to Good Manufacturing Practice (GMP) and Quality Systems Regulations (QSR), and is specific to the cleaning method and agent employed. A cleaning validation involves testing for acceptable levels of detergents residue on pharmaceutical manufacturing or medical device surfaces following equipment cleaning processes. CHEMetrics® Detergents Test Kit, Cat. No. K-9400, featuring a superior extraction/sampling technique, is routinely used by pharmaceutical companies to measure detergents to ensure that no excessive residual surfactant remains.

What are Detergents?

A detergent is a surfactant, or mixture of surfactants, with cleaning properties in diluted solution, designed to remove dirt from surfaces, to allow oils and water to mix and to form foam. Detergent and soap differ in that synthetic detergent is made from petroleum fractions whereas soap is manufactured from natural ingredients, primarily vegetable oils. The term ‘surfactant’ is derived from suface-active agent. Surfactants are chemical compounds that lower the surface tension between a liquid and either another liquid, gas or solid.

Surfactant molecules are characterised by their hydrophilic (water-attracting) head and their longer hydrophobic (water repellent) tail. Surfactant cleansing action is via a structure called a micelle which is a type of colloidal particle formed when the hydrophobic tails attach to dirt or grease particles while the hydrophilic heads point out. Micelles lift the dirt off of the surface and may contain tens or hundreds of atoms, ions or molecules.

Surfactants are classified by the charge on the hydrophilic head. If the hydrophilic head has a negative charge is called an anionic surfactant (e.g. alkyl sulphate, sulphonate, phosphate and carboxlyates.) Anionic surfactants are the most common kind of surfactants used in detergents. If the hydrophilic head has a positive charge, it is called a cationic surfactant (e.g. QUATs/QACs and pH-dependent primary, secondary or tertiary amines). Zwitterionic surfactants have both cationic and anionic functional groups attached the the same molecule. If the hydrophilic head has no charge, it is called a non-ionic surfactant, e.g. fatty alcohol or alkyl phenol ethoxylate, and fatty acid alkoxylate. Non-ionic surfactants have covalently-bonded oxygen-containing hydrophilic groups and dissolve in water through the formation of hydrogen bonds with the oxygen atom(s) in the head.