Demeestere, Kristof

Huysman, Steve

Van Langenhove, Herman

Vanhaecke, Lynn

Vanryckeghem, Francis

English

Ghent University Academic Bibliography

Environmental forensics in seawater by coupling a divinylbenzene passive sampling device and high resolution mass spectrometry for the screening of organic micropollutants Huysman Steve1, Vanryckeghem Francis2, Van Langenhove Herman2, Demeestere Kristof2 ,and Vanhaecke Lynn1 1Ghent University, Department of Veterinary Public Health and Food Safety, Laboratory of Chemical Analysis (LCA), Merelbeke, Belgium 2Ghent University, Department of Sustainable Organic Chemistry and Technology, Research Group Environmental Organic Chemistry and Technology (EnVOC), Ghent, Belgium E-mail contact: Steve.Huysman@Ugent.be and Lynn.Vanhaecke@Ugent.be  1. Introduction Many organic micropollutants, such as pharmaceuticals, personal care products, pesticides, phenols, phthalates, natural and synthetic steroids have received special attention because of their omnipresence in the environment. Frequently, these compounds find their way into the environment as water pollutants, whether or not metabolised or as degradation products, resulting in some constraints towards environmental monitoring [1]. While triple quadrupole analyzers currently enable only a predefined list of compounds in samples, high resolution mass spectrometry (HRMS) makes it possible to detect a virtually unlimited number of compounds in a single run without preselection. Nevertheless, the range of physico-chemical properties of micropollutants detected is limited by sample pre-treatment, chromatographic and ionization conditions. In addition, micropollutants are present in the aquatic environment at sub-ppb concentrations and at varying occurrence, both in time and location. Usually, water samples are collected by grab samples, providing a snapshot of the contamination level at a given time and place. A better knowledge of these variables can be achieved by using passive samplers [2]. To overcome these constraints and improve environmental monitoring, this study coupled the use of divinylbenzene (DVB) passive samplers with in-house validated UHPLC-HRMS methodologies. Two UHPLC-HRMS methods were used to detect micropollutants in the marine environment to eliminate their physico-chemical preferences. 2. Materials and methods 2.1. Sampling sites Grab and passive sampling were done at the same sites and time. The DVB passive samplers were deployed during 2 months at three locations in the Belgian Part of the North Sea (BPNS); i.e. the harbour of Oostende (51.22263°, 2.9357°), the harbour of Zeebrugge (51°N 21.609’, 30E 8.0806’), and more offshore, at open sea (51.336°, 3.1992°). 2.2. Samples and treatment Grab samples were extracted using Oasis HLB for concentrating pharmaceuticals, pesticides and personal care products, whereas DVB-SPE was employed for the natural and synthetic steroids. The passive samplers contained DVB to collect a broad range of micropollutants, extracted in a similar way as the DVB devices used during grab sample extraction. Field blanks were treated in the same manner as the exposed DVB passive samplers. 2.3. UHPLC-HRMS analysis Two in-house validated UHPLC-HRMS methods (not yet published) enable the separation of the micropollutants using a Hypersil Gold column (1.9 mm, 2.1 µm) and different gradient elution programs and ionization sources (HESI and APCI).  Detection was done by Q-Exactive Orbitrap mass spectrometry, resulting in the measurement of known (target), suspected and unknown (non-target) compounds. 2.4. Databases and data processing The identification of compounds was enabled by their chromatographic retention time and mass spectrometric (accurate mass and C13/C12 isotope ratio) properties. In order to facilitate and improve the identification process, three databases were used: a target, a suspect, and a non-target database. The three were respectively processed by XCalibur™ 2.07, ToxFinder™ 1.0, and Sieve™ & Simca ™ 2.2 (Thermo Scientific). The target database contained over 145 organic micropollutants, and included their accurate mass, retention time, and C13/C12 isotope ratio, determined by injecting individual reference standards. The compounds included were pharmaceuticals, personal care products, pesticides, natural and synthetic steroids. The suspect database, which was based on scientific literature research, contained the accurate mass and theoretical C13/C12 isotope ratio of 380 suspected organic micropollutants. The non-target database uses the detected accurate masses processed by multi-variate analysis for coupling it back to the ChemSpider online database for further identification. 3. Results and discussion 3.1. Target screening The target screening was performed on both the grab and passive samples. Less synthetic and natural steroids (Fig. 1) were found in the passive samplers in comparison with the grab samples at the same locations, whereas more pesticides, pharmaceuticals and personal care product were found in the passive samplers.   Figure 1. The target screening, including the synthetic and natural steroids of the grab and passive samplers. 3.2. Suspect and non-target screening The suspect screening of passive samplers revealed the occurrence of 124 different micropollutants. Non-target screening demonstrated additionally 14 emerging organic pollutants, with a compound correlation score higher than 98%, co-occur at each location. Furthermore, the non-target screening was able to discriminate the different sample locations using multi-variate analysis on the detected accurate masses. 4. Conclusions This study demonstrates that DVB passive samplers used in combination with high resolution mass spectrometry analysis is a promising tool for screening the micropollutant status of the marine environment. DVB is able to capture a broad spectrum of organic micropollutants, whereas HRMS makes it possible to identify target, suspected and non-target compounds in one single injection. Futhermore, the statistical PCA-methodology revealed differences of molecular fingerprinting and co-occurrence of unknown compounds in each deployed passive sampler. More locations in the BPNS (51°33,65'N - 2°59,10'E; 51.234499’N, 2.927175’E and 51.340073’N, 3.203393’E) will be sampled and analysed for extending the dataset obtained through this new methodology, of which the results will be presented during the conference. 5. References [1] A. Müller. 2011. Chemosphere 85. A new approach to data evaluation in the non-target screening of organic trace substances in water analysis. 85, 1211–1219. doi:10.1016/j.chemosphere.2011.07.009. [2] D.A. Alvarez. 2014. Marine Pollution Bull 81. Occurrence of contaminants of emerging concern along the California coast ( 2009 – 10 ) using passive sampling devices. 347–354. doi:10.1016/j.marpolbul.2013.04.022.    

Environmental forensics in seawater coupling a divinylbenzene passive sampling device and high resolution mass spectrometry for the screening of micropollutants

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Environmental forensics in seawater coupling a divinylbenzene passive sampling device and high resolution mass spectrometry for the screening of micropollutants

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