You can check the performance of your titrator by periodically running water standards such as those supplied with Cou-Lo Formula reagents. Although in principle standardisation of a coulometer is not necessary since the water “titrated” is a direct function of the coulombs of electricity consumed, the ASTM methods for measuring water content of crude oil and petroleum products stipulate that the performance of the coulometer be regularly monitored by injecting 10 microlitre of pure water. The suggested interval is after every 10 determinations and the result obtained should be 10,000 +/- 200 microgram. The reagent should be changed if the result is outside these limits.
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