Articles
Mercury Analysis in Water – How to Validate Your Results
Posted by: chrisball | Posted on: May 1st, 2012 | 0 Comments
When measuring mercury at sub pg/g level, there is a strict quality control procedure you need to comply.
1) You need to prepare at least 5 calibration standards, with the lowest standard being 0.5 pg/g or 1 pg/g depending on you are in America or Europe.
2) The linearity of the calibration curve needs to be in a accepted range
3) The intercept of the calibration curve needs to be less than half of the slope
4) The recovery of the lowest standard need to be within certain range
5) An ‘on going standard’ needs to be used for controlling the drift
6) An ‘independent standard’ needs to be prepared by another person or from independent source to ensure the accuracy of the calibration standards
7) The usage of reference material is highly recommended
8) Random sample needs to be spiked in duplicate, the spike recoveries of these two sample need to be within certain range
Mercury Analysis in Water – Avoid Background Contamination
Posted by: chrisball | Posted on: April 16th, 2012 | 0 Comments
It is imperative to keep the background level under control otherwise you fail the QC automatically because of it. The high mercury background can come from the following sources: Deionized water Hydrochloric acid Tin(II) chloride Bromine solution Hydroxylamine hydrochloride Containers Carrier gas — argon Your lab environment Personal hygiene
How to lower the background Use highest purity available for the chemicals Keep the concentrations as low as possible Use clean containers Boil your reductant and then purge it Filter your argon carrier gas Operate in environment Change gloves often to avoid cross contamination.
