Analysis of Aqueous Alkanolamines using Hydrophilic Interaction Liquid Chromatography and Mass Spectrometr
2013 (English)In: Analytical Chemistry Letters, ISSN 2229-7928, Vol. 3, no 5-6, 298-313 p.Article in journal (Refereed) Published
A method for determination of mono-, di-, triethanolamine (EA, DEA, TEA), iso-, N-propanolamine (IPA, NPA), diisopropyl ethanol amine (DIPEA), 2-diethylethanol amine (DEEA), diisopropanol amine (DIPA), dimethylethanol amine (DMEA), N-methyldiethanol amine (MDEA) in aqueous solutions is presented. Separation was achieved by zwitterionic hydrophilic interaction liquid chromatography (ZIC-HILIC). Injections of aqueous solutions were enabled by on-column focusing with partially filled loop injections. The ZIC-HILIC was coupled with a tandem mass spectrometer (MS/MS) with electrospray ionisation monitoring of positive ions. Linear calibration graphs (0.04-3.0 μg mL-1, n = 9) were obtained with correlation coefficients in the range of >0.96 using N-tripropyl amine (NTPN) as internal standard and >0.99 using NPA as internal standard. The instrumental detection limit was below 44 fmol.
Chromatographic separation of the 10 studied alkanolamines was achieved. The most suitable composition of the focusing liquid was determined to be 1:1 AcCN/AcO, enabling injection volumes up to 3 µL whilst maintaining the chromatographic characteristics. The optimal solvent composition was found to be 100 % water with 0.01 % acid at pH < 4. Sample solution concentrations of 1.0 µg mL-1 could be injected on the column with sustained chromatography.
To maintain stable chromatography the column needed to be regenerated after approximately 500 injections. A minimum of 5 minutes equilibration time between runs was required. The importance of equilibration was also observed after regeneration of the column to obtain chromatographic stability (peak shape and retention times), especially for the compounds eluting close to the front.
Characterisation of the MS fragmentation pattern for the alkanolamines by hydrogen-deuterium exchange indicated a main loss of one or more water molecules. For secondary and tertiary alkanolamines the loss of an alkyl-group and/or alkanol-group was also seen.
The possibility of using the method for determining alkanolamines in metal working fluids and in air samples was demonstrated.
Place, publisher, year, edition, pages
2013. Vol. 3, no 5-6, 298-313 p.
Alkanolamine, HILIC, LC-MSMS
Research subject Analytical Chemistry
IdentifiersURN: urn:nbn:se:su:diva-94064DOI: 10.1080/22297928.2013.861166OAI: oai:DiVA.org:su-94064DiVA: diva2:651122