Analysis of oilfield produced waters and production chemicals by electrospray ionisation multi-stage mass spectrometry (ESI-MSn)

Large quantities of diverse polar organic chemicals are routinely discharge d from oil production platforms in so-called produced waters. The environme ntal fate of many of these is unknown since few methods exist for their cha racterisation. Preliminary investigations into the use of multistage electr ospray ionisation ion trap mass spectrometry (ESI-MS') show its potential f or the identification and quantification of compounds in specialty oilfield chemicals (corrosion inhibitors, scale inhibitors, biocides and demulsifie rs) and produced waters. Multiple stage mass spectrometry (MS') with both p ositive and negative ion detection allows high specificity detection and ch aracterisation of a wide range of polar and charged molecules. For example, linear alkylbenzenesulfonates (LAS), alkyldimethylbenzylammonium compounds , 2-alkyl-1-ethylamine-2-imidazolines, 2-alkyl-1-[N-ethylalkylamide]-2-imid azolines and a di[alkyldimethylammonium-ethyl]ether were all identified and characterised in commercial formulations and/or North Sea oilfield produce d waters. The technique should allow the marine environmental effects and f ates of some of these polar compounds to be studied. (C) 2001 Elsevier Scie nce Ltd, All rights reserved.