Guidelines For Turbidity Measurements; Cleaning Of Vials & Sampling Containers - VWR TIR 200 Mode D'emploi

Guidelines for turbidity measurements

a) Vials and caps should be cleaned thoroughly after each test to avoid interferences. Minor
residuals can cause errors.
b) The outside of the vial must be clean and dry, before starting the test. Wipe the vials with
a smooth cloth to remove fingerprints or waterdrops.
c) The vials must be positioned in the sample chamber with the mark on the vial aligned
with the mark on the instrument.
d) Always perform the test with securely capped vials.
e) Bubbles on the inside of the vial lead to errors.
See chapter "Removing bubbles (Degassing)".
f) Avoid spillage of water in the sample chamber. If water should leak into the instrument,
it can destroy electronic components and cause corrosion.
g) Contamination of the lens in the sample chamber can result in errors. Check at regular
intervals – and if necessary – clean the light entry surfaces of the sample chamber using
a moist cloth or cotton buds.
h) Large temperature differences between the instrument and the environment can lead to
errors – e.g. due to the formation of condensation in the area of the lens or on the vial. For
best results, perform tests with sample temperatures between 20°C (68°F) and 25°C (77°F).
i) To avoid errors caused by stray light do not use the instrument in bright sunlight.
j) Use the instrument in a clean, dust-free environment on a table that is free from vibra-
tion / agitation.
Cleaning of vials & sampling containers
Vials, caps and sampling containers should be cleaned thoroughly after each test to avoid
interferences. Minor residuals can cause errors.
Residuals:
The vial must be cleaned according to the type of sample measured.
• Replace scratched vials immediately.
• Rinse vials thoroughly with deionised water after each measurement.
• Clean all glassware thoroughly with laboratory detergent and rinse with deionised water.
14 VWR ver 1 01/2018