Direct detection of polyaromatic hydrocarbons, estrogenic compounds and pesticides in water using desorption chemical ionisation membrane inlet mass spectrometry

Abstract

This paper describes the use of desorption chemical ionisation membrane inlet mass spectrometry (DCI-MIMS) for the detection of a broad range of common contaminants in water. In addition, we discuss the advantages/disadvantages of two different types of chemical ionisation reagent gases, i-butene (a Broensted acid reagent) and argon (a charge exchange reagent). We found that polyaromatic hydrocarbons was detectable at ppt levels, the estrogenic compounds diethyl phthalate and octylphenol at high ppt levels, steroid hormones at ppb levels, hydrophobic pesticides at low ppb levels, whereas hydrophilic pesticides and bisphenol A were not detectable at all. With the exception of the polyaromatic hydrocarbons and pentachlorophenol, none of the reported compounds have to our knowledge been detected previously by other MIMS systems. In most cases the Broensted acid reagent gave characteristic ions at high mass/charge ratio, whereas the charge exchange reagent gave less characteristic ions at low m/z ratio. However, the sensitivity was generally not as good with the Broensted acid reagent as with the charge exchange reagent, since the Broensted acid reagent, i-butene, gave a large chemical background.

Condensed Phase Membrane Introduction Mass Spectrometry with Direct Electron Ionization: On-line Measurement of PAHs in Complex Aqueous Samples

“…Although PAHs are very hydrophobic (typical log K ow values in the 3-6 range [16]), making them well suited for PDMS based MIMS measurements, their low volatilities make their direct, on-line measurement by GP-MIMS problematic. Thermally assisted GP-MIMS approaches have been used to measure selected PAHs [18][19][20][21]. Although demonstrating potential on-line analytical capability for PAHs, eliminating the need for thermal desorption would simplify their measurement.…”

Characterization of a sheet membrane interface for sample introduction into a time-of-flight mass spectrometer

“…Membrane inlet mass spectrometry (MIMS) has come into widespread use for the direct sampling and mass analysis of volatile organic compounds (VOCs) at trace levels in water and air [1][2][3][4][5][6][7]. MIMS allows the direct introduction of specific components of a liquid or gas sample into a mass spectrometer.…”

An in-source stretched membrane inlet for on-line analysis of VOCs in water with single photon ionization TOFMS

“…However, the pressure of 10 À3 Pa inside the SPI source limited the sample input, and the limit of detection (LOD) of benzene was only 25 mg L À1 . Other types of membrane inlet have also been developed to improve the performance of on-line mass spectrometry, [13][14][15][16][17][18][19][20][21][22][23][24] such as the direct external probe hollow ber membrane (HFM), 25 the direct ow-through HFM probe, 13,26 the trap-and-release HFM, 15,21 the intermediate pressure region membrane and the single-side membrane etc.…”