High performance liquid chromatography (HPLC)

OELCHECK test instrument: HPLC System UltiMate 3000 Thermo Fisher Scientific
Sample quantity: approx. 500 µL
Unit: mg/L
Test result: content of organic acids (adipic acid, benzoic acid, 2-ethylhexanoic acid, sebacic acid, octanoic acid, isononanoic acid, toluic acid, mercaptobenzothiazole, tolyltriazole, benzotriazole)
Analysis for: coolants
Brief description: A few microliters of the diluted sample are placed on a chromatographic separation column using a mobile phase. Due to the polar interactions, the analytes remain on the stationary phase of the column with varying degrees of force. The sample is therefore divided into the individual analytes. The analytes gradually elute by means of a gradient at which the unpolar amount in the mobile phase is increased. After separation, the analytes are recorded by a diode array detector after separation at a characteristic retention time.
Statement: The organic acids are used as corrosion inhibitors in the coolants. The HPLC analysis shows if a coolant has the expected amount of inhibitors. In this way, mixing and additive degradation can be identified.
Underlying test standard: OELCHECK test method OPM 105