Inorganic chloride (Cl−) is a major contaminant of petroleum hydrocarbons and already at the parts-per-million level its detrimental effects on industrial processes are well documented. Cl− acts as an inhibitor of catalysts used in refineries, it forms encrustations, and during the processes, it may be converted to hydrochloric acid which is highly corrosive to the infrastructure. The determination of Cl− in oil is a notoriously challenging task. Despite several analytical methods have been described, none of them meets the required sensitivity, specificity and ease-of-implementation. In this talk, we present a novel approach for Cl− determination in crude oil based on gas chromatography tandem mass spectrometry (GC−MS/MS). The procedure required an initial 1:10 dilution of the sample followed by a single-step derivatization at room temperature. This simple sample preparation allowed the conversion of Cl− into volatile chloroethane which was detected by selective headspace GC−MS/MS (run time: 5 min; throughput: 12 samples/hour). With a detection limit of 20 mg kg-1, the method provided for unmatched sensitivity. The procedure was tested on the NIST SRM 1634c standard with a Cl− recovery of 109% (n = 15, RSD = 2.0%).

Accurate and sensitive method for the determination of inorganic chloride in petroleum hydrocarbons

2019 Spring National Meeting

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