Investigation of the Agilent 5977B with High Efficiency Source (HES) to Enable Electron Impact (EI) Analysis of Phenolic Compounds in Water

Martin Perkins

20th June 2018


Phenolic compounds are a group of chemicals which are detectable to the human palate as metallic tastes at low concentrations in drinking water.  The reaction of hypochlorite and phenolic acids produces chlorinated phenols as a by-product as does the degradation of phenoxy herbicides. In order to improve chromatography, phenolic compounds are routinely derivatised prior to Gas chromatographic (GC) analysis. Traditionally the Pentafluorpbenzoyl chloride (PFBCl) derivatives  of chlorinated phenols would be analysed using an electron capture detector or Negative Chemical Ion (NCI) source. The aims of this study were twofold; to automate the current extraction procedure and see if the improved sensitivity from the latest Agilent 5977B single quadrupole mass spectrometer with High Efficiency Source (HES) would facilitate a direct conversion of a method with NCI source to Electron Impact (EI) source. As well as the advantages of automation, this conversion to EI analysis may be preferential for many laboratories due to the cost savings of NCI reagent gases, having to have an instrument dedicated to NCI, or not having to switch sources between methods. The automated solution affords 60 samples to be prepared and run in a 24 hour period, which is an increase in 100% compared to the manual method. Peak response and linearity were assessed for 26 phenolic and chlorophenolic compounds and initial results were promising, although further optimization would be required, such as the use of an alternative derivatising agent as described in AS168. The improved sensitivity of the 5977B can offer the option of different approach to using NCI for phenols in water.

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