Analysis of oilfield chemicals by electrospray mass spectrometry

Recently we demonstrated the potential of electrospray-mass spectrometry (E S-MS) for the qualitative analysis of several important classes of oilfield production chemicals, including emulsion breakers, corrosion inhibitors, s cale inhibitors and sequesterants. Particular advantages of ES-MS are that it is sensitive, it produces mainly molecular ions, and it is simple to aut omate and to interface with liquid chromatography (LC), Here we extend the scope of our preliminary loop injection analysis study to include the analy sis of quaternary ammonium and imidazoline corrosion inhibitors by on-line high performance liquid chromatography (HPLC) MS. This will demonstrate the potential of LC interfaced to ES-MS for the characterisation of structural ly complex oilfield chemicals. Furthermore, the ability of this technique t o quantify residual corrosion inhibitors in oilfield fluids has been invest igated. Quantitative data provides a gain of at least two orders of magnitu de sensitivity over the LC-diode array methodology previously used and also provides the specificity of the mass spectrometric information. Copyright (C) 1999 John Wiley & Sons, Ltd.