Extran® Cleaning Validation

Ensure Residue-Free Cleaning

Many facilities are required to prove residue-free cleanliness of their lab equipment – because the accuracy of analytical results crucially depends on absolute purity of the lab utensils used. With Extran®, Merck offers a full range of powerful detergents for laboratory washing that reliably remove even the most stubborn contaminants, thus preventing carry-over of residues to the next analysis. In order to simplify cleaning validation for Extran® detergents, Merck offers an easy-to-perform photometric method for verifying that no detergent residues remain after laboratory cleaning.

Feature and Benefits

• Cleaning validation support
• More comfort
• Reliable, accurate results

Extran® Laboratory Cleansers

With our wide range of Extran® detergents for manual as well as automated cleaning procedures, we offer you cleaning solutions tailored to every conceivable laboratory application.

Our Extran® MA products for manual cleaning are concentrates for universal use in the preparation of aqueous cleansing baths. Merck's Extran® grades for automated cleansing have been specially developed in close cooperation with leading instrument manufacturers in order to ensure suitability for and compatibility with the washing machines in your laboratory. Featuring an extremely low degree of foam formation and excellent water solubility, Extran® cleans lab instruments without leaving unwanted residue.

Extran® is free from chlorine, dyes, scents and other toxic ingredients, and fulfills all requirements with respect to biodegradability and phosphate content. Its active substances fully comply with the specifications of (EC) directive 648/2004. Extran® detergents come with helpful documentation including a 2-page flyer describing the photometric determination of Extran® residues in aqueous solutions.

Photometric Extran® Determination

Residue determination in aqueous solutions with Spectroquant® cell test

Many Extran® users need to be absolutely sure that no detergent residues remain after washing their equipment. Photometric determination of Extran® in water and rinse solutions using Merck's Spectroquant cell test for non-ionic surfactants provides practical, easy-to-perform cleaning validation support.

In this method, non-ionic surfactants react with an indicator (TBPE) to form a complex which is then extracted using dichloromethane. The green color of the organic phase is determined photometrically. Merck's user-friendly Spectroquant cell tests already contain all reagents necessary for the analysis. A bar code printed on each cell prevents mistakes: When the cell is inserted into the photometer, the correct method is automatically selected.

Photometric Extran® residue determination is suitable for the Extran® grades MA01, MA02 and MA05 for lab washing machines. The method is described in detail in an application guide we provide with every Extran® product.

Step by Step

Performing a photometric Extran® residue determination is simple

1. First filter the sample, if needed (the sample must be clear), and dilute it with water into the measuring range of the Spectroquant cell test (0.1 to 7.5 mg/l). pH should be adjusted into the range 3-9, if necessary, using sodium hydroxide solution or sulfuric acid provided in the test kit. For rinse solutions, measure an Extran® free rinse solution as blank value. 
    
2. Immediately after sample preparation, add 4 ml sample to the cell test and shake vigorously for 1 min. After additional 2 minutes reaction time, insert the cell into the photometer. A clear phase separation must occur within the reaction time, whereas an emulsion would indicate that Extran® concentrations in the tested sample are too high.
    
3. Swirl the cell, then measure the sample in the photometer. The appropriate method is already stored and automatically selected in Spectroquant colorimeters and photometers such as NOVA 60 or Pharo 100 / 300. Other suitable photometers can be used as well, provided that 16 mm round cells are useable and the photometer gives read-outs for 605 nm against cell test blank value.