What is the procedure for cleaning sample cells?

Document ID

Document ID TE967

Version

Version 3.0

Status

Status Published

Published Date

Published Date 10/11/2018
Question
What is the procedure for cleaning sample cells?
Summary
Procedure for cleaning sample cells
Answer
In general, laboratory detergents can be used to clean sample cells. Most laboratory detergents can be used at recommended concentrations. Neutral detergents, such as Liqui-Nox®, are safer when regular cleaning is required. Cleaning times are reduced by increasing the temperature or by using an ultra-sonic bath. Finish by rinsing a few times with deionized (DI) water and allow to air dry.

Individual procedures may require special cleaning methods. When using a brush to clean cells, take extra care to avoid scratching the inner surfaces of the cells.

Acid washing is recommended when testing for low-level metal concentrations or for sample cells used for turbidity measurement. Avoid letting the acid come in contact with the outside of the sample cell as this may result in accidental removal of sample cell markings. If a procedure suggests acid washing, follow these steps:
  1. Clean the glassware or plasticware with laboratory detergent. Phosphate-free detergent is best (when determining phosphate, a phosphate-free detergent must be used).
  2. Rinse well with tap water.
  3. Rinse with a 1:1 Hydrochloric acid or 1:1 nitric acid solution (nitric acid is best when testing for lead or other metals).
  4. Rinse well with DI water. For chromium, 12-15 rinses may be necessary. When determining ammonia and Kjeldahl nitrogen, the rinse water must be ammonia-free.
  5. Air dry the container. Protect the glassware from fumes or other sources of contamination during storage.
Use chromic acid or chromium-free substitutes to remove organic deposits from glass containers. Afterwards, rinse thoroughly with water to remove all traces of chromium. Avoid introducing metal contaminants from containers, distilled water or membrane filters.
 

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