title: Trace analysis of total naphthenic acids in aqueous environmental matrices by liquid chromatography/mass spectrometry-quadrupole time of flight mass spectrometry direct injection.
abstract: A rapid and sensitive liquid chromatography quadrupole time of flight method has been established for the determination of total naphthenic acid concentrations in aqueous samples. This is the first methodology that has been adopted for routine, high resolution, high throughput analysis of total naphthenic acids at trace levels in unprocessed samples. A calibration range from 0.02 to 1.0μgmL(-1) total Merichem naphthenic acids was validated and demonstrated excellent accuracy (97-111% recovery) and precision (1.9% RSD at 0.02μgmL(-1)). Quantitative validation was also demonstrated in a non-commercial oil sands process water (OSPW) acid extractable organics (AEOs) fraction containing a higher percentage of polycarboxylic acid isomers than the Merichem technical mix. The chromatographic method showed good calibration linearity of ≥0.999 RSQ to 0.005μgmL(-1) total naphthenic acids with a precision <3.1% RSD and a calculated detection limit of 0.0004μgmL(-1) employing Merichem technical mix reference material. The method is well suited to monitoring naturally occurring and industrially derived naphthenic acids (and other AEOs) present in surface and ground waters in the vicinity of mining developments. The advantage of the current method is its direct application to unprocessed environmental samples and to examine natural naphthenic acid isomer profiles. It is noted that where the isomer profile of samples differs from that of the reference material, results should be considered semi-quantitative due to the lack of matching isomer content. The fingerprint profile of naphthenic acids is known to be transitory during aging and the present method has the ability to adapt to monitoring of these changes in naphthenic acid content. The method's total ion scan approach allows for data previously collected to be examined retrospectively for specific analyte mass ions of interest. A list of potential naphthenic acid isomers that decrease in response with aging is proposed and a quantitative assay of an adamantane carboxylic acid is reported.
authors.affiliation: Pacific and Yukon Laboratory for Environmental Testing, Science & Technology Branch, Pacific Environmental Science Centre, Environment Canada, North Vancouver, British Columbia, Canada.
authors.forename: Pamela
authors.initials: P
authors.lastname: Brunswick
authors.affiliation: Pacific and Yukon Laboratory for Environmental Testing, Science & Technology Branch, Pacific Environmental Science Centre, Environment Canada, North Vancouver, British Columbia, Canada. Electronic address: dayue.shang@ec.gc.ca.
authors.forename: Dayue
authors.initials: D
authors.lastname: Shang
authors.affiliation: Pacific and Yukon Laboratory for Environmental Testing, Science & Technology Branch, Pacific Environmental Science Centre, Environment Canada, North Vancouver, British Columbia, Canada.
authors.forename: Graham
authors.initials: G
authors.lastname: van Aggelen
authors.affiliation: Vogon Laboratory Services Ltd., Calgary, Alberta, Canada.
authors.forename: Ralph
authors.initials: R
authors.lastname: Hindle
authors.affiliation: Aquatic Contaminants Research Division, Environment Canada, Burlington, Ontario, Canada.
authors.forename: L Mark
authors.initials: LM
authors.lastname: Hewitt
authors.affiliation: Aquatic Contaminants Research Division, Environment Canada, Burlington, Ontario, Canada.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Frank
authors.affiliation: Caro Analytical Services, Richmond, British Columbia, Canada.
authors.forename: Maxine
authors.initials: M
authors.lastname: Haberl
authors.affiliation: Agilent Technologies Inc., Ontario, Canada.
authors.forename: Marcus
authors.initials: M
authors.lastname: Kim
mesh_terms: D002264:Carboxylic Acids / Q000008:administration & dosage*; D002853:Chromatography, Liquid / Q000379:methods; D060587:Groundwater / Q000737:chemistry*; D007536:Isomerism; D057230:Limit of Detection; D008906:Mining; D061329:Oil and Gas Fields; D053719:Tandem Mass Spectrometry / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D002264:Carboxylic Acids; D014874:Water Pollutants, Chemical; C046170:naphthenic acid
keywords: Environmental; Isomers; Merichem; Naphthenic; OSPW; QToF