Why do the TNT866 and TNT867 methods for Free and Total Chlorine require a zeroing vial?

Document ID

Document ID TE3965

Version

Version 2.0

Status

Status Published

Published Date

Published Date 27/05/2017
Question
Why do the TNT866 and TNT867 methods for Free and Total Chlorine require a zeroing vial?
Summary
TNT866 and TNT867 requirement of a zeroing vial
Answer
The Chlorine TNTplus reagents (TNT866 & TNT867) require a zeroing vial because lot-to-lot variability cannot be controlled to the same extent as some of the other reagents. This ensures the most accurate results.
The calibration of the instrument is based on the absorbance of the zeroing vial (i.e. Reagent Blank) and it is always mandatory to zero the instrument with the zero vial. If a sample is colored, then it is recommended to use TNT919 in addition to serve as the sample blank.
TNT919 is a sample blank vial (emtpy vial) that is recognized as such by it sbarcode and is automatically subtracted from the final result of an analysis vial.