Palintest

June 28, 2005
Palintest offers easy-to-use organo-phosphonate monitoring test

Palintest has introduced an improved, easy to use  organo-phosphonate test for monitoring OP levels in boiler and cooling water  systems.  Using a specially  developed tablet containing a pH buffer and screened indicator, this new test  eliminates the problems of pH adjustment and end-point determination associated  with the traditional test, making it more consistent and more  accurate.

Low levels of organo-phosphonate  compounds are now used worldwide as scale and corrosion inhibitors in boiler and  cooling water applications.   Monitoring is essential to ensure the treatment is fully effective but,  until now, this has been problematic and testing has produced questionable  results.

The level of OP in a solution is  ascertained by measuring the volume of a thorium nitrate reagent required to  complete a reaction with it, using xylenol orange as an indicator.  Traditionally, this had to be done under  precise pH conditions, often requiring a pH correction procedure first, and the  result was difficult to determine due to a poor color  change.

The Palintest OP test uses a tablet which combines a  pH adjuster and buffer mixture together with a screened xylenol orange  indicator.  This is simply dissolved  in thesample to provide the correct pH conditions for the  test.  The screened indicator then  produces an obvious color change from green to purple only as the decisive drop  of thorium nitrate is added.  The  microburette for adding the thorium nitrate is directly calibrated to OP  concentration and provides a readout to a precision of  0.4mg/l.