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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 1.0 μg mL −1 total Merichem naphthenic acids was validated and demonstrated excellent accuracy (97–111% recovery) and precision (1.9% RSD at 0.02 μg mL −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 0.005 μg mL −1 total naphthenic acids with a precision <3.1% RSD and a calculated detection limit of 0.0004 μg mL −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. [ABSTRACT FROM AUTHOR]

• Rapid, direct injection LC/MS-QTOF method for resin acids without derivatization. • MDL in range 0.05 to 0.07 µgL−1 for six resin acids in aqueous alkaline matrix. • Precision and accuracy from 1 µgL−1 to 40 µgL−1 in matrix. • Isopimaric as calibrant for six C 20 H 30 O 2 resin acids. • Transferred to LC/MS/MS and successfully applied to environmental samples. A rapid and sensitive liquid chromatography (LC) quadrupole time of flight (QTOF) method has been developed for the determination of resin acid concentrations in aqueous pulp and paper effluent related samples. Calibration R2 of ≥0.995 for twelve resin acids, namely dehydroabietic, 8(14)-abietenic, dihydroisopimaric, levopimaric, neoabietic, pimaric, sandaracopimaric, abietic, isopimaric, palustric, chlorodehydroabietic, and dichlorodehydroabietic acids, was demonstrated in the range 1 µgL−1 to 40 µgL−1. An improved lower limit of quantitation was achieved without use of complex sample extraction and clean-up procedures undertaken by other published methods. Excellent precision and accuracy results were achieved for dehydroabietic, chlorodehydroabietic, dichlorodehydroabietic, isopimaric (integrated inclusive of all C 20 H 30 O 2 resin acids), dihydroisopimaric and 8(14)-abietenic resin acids, with t-99 percentile detection limits spanning the range 0.05 to 0.07 µgL−1. While measurement for the C 20 H 30 O 2 resin acids by isopimaric equivalence is considered semi-quantitative and could be an under estimate for the abietic acid component, the developed method demonstrated clear advantage over time consuming, hazardous, and unstable derivatization procedures used for gas chromatography and capillary electrophoresis. The developed LC/QToF method was successfully transferred to an LC triple quadrupole mass spectrometer for routine high throughput trace level analysis. Real world samples, including sea water and estuary water, demonstrated excellent spike recoveries by this procedure, indicating that the method is well suited to the monitoring of industrially derived resin acids in environmental surface waters. While no interferences were observed during routine sample analysis using myristic-1-13C acid and palmitic-1-13C acid internal standards, these were later substituted by myristic-d 27 and palmitic-d 31 acid in order to improve method robustness for environmental samples where endogenous parent fatty acids could be present. [ABSTRACT FROM AUTHOR]