Better 'Tools' for Investigative Monitoring under the Water Framework Directive by Anthony Gravell

519 Pages·2017·9.83 MB·English

Better ‘Tools’ for Investigative Monitoring under the
Water Framework Directive

by
Anthony Gravell

A Thesis Submitted to the University of Portsmouth
In Partial Fulfilment of the
Requirements for the Degree of
DOCTOR OF PHILOSOPHY
May 2017
Abstract
Current approaches to sampling and analysis are thought to be unsuitable for
investigative monitoring under the auspices of the European Union’s Water
Framework Directive. During this study, new sampling and analytical techniques
were developed and tested that provide a ‘toolkit’ that can be utilised by most
laboratories engaged in regulatory analysis of water samples. The techniques
developed include;

i) Targeted screening methodology based on passive sampling in-conjunction
with comprehensive two-dimensional chromatography mass spectrometry was
developed and successfully applied to the broad-scope detection and
determination of non-polar emerging pollutants and related contaminants in
environmental waters. This method was found to be superior to existing
approaches based on spot sampling and one dimensional gas chromatography.

ii) Modifications to the Chemcatcher® passive sampler to allow for the sampling
of polar pollutants present in the water environment. Statistical analysis of the
data obtained demonstrated that sampler performance was equivalent to that
of the established POCIS passive sampler but with greater physical robustness
together with simplified preparation and extraction procedures.

iii) Targeted screening methodology based on modifications to the existing
Chemcatcher® passive sampler in-conjunction with liquid chromatography-
high resolution mass spectrometry techniques for the identification of polar
pharmaceutical residues present in the effluents of waste water treatment
ii
plants located in south west Wales. Identification of analytes was strengthened
through the development, validation and application of a novel accurate mass
data-independent acquisition method and the high degree of analyte
identification assurance obtained confirmed it to be analogous to traditional
collision-induced dissociation transitions.

iv) The targeted application was supplemented through the development and
application of a novel in silico methodology for retention time prediction
which was successfully used to identify additional compounds in an extract
obtained from a Chemcatcher passive sampler, and, thus, the preliminary
identification of potential emerging contaminants.

Overall, this work has furthered the knowledge and capability of the sampling and
analysis of existing and newly emerging contaminants in environmental waters.

iii
Contents
List of Tables xiii
List of Figures xvii
List of Abbreviations xxviii
Acknowledgements xxxiii
Dissemination xxxiv

Chapter 1 1
Literature review
1.1 The European Union’s Water Framework Directive (WFD) 2
1.2 Monitoring under the WFD 4
1.3 Existing approaches to WFD investigative monitoring of organic chemicals 5
1.4 Sampling techniques for the determination of organic contaminants 6
in the aquatic environment
1.5 Extraction techniques for organic contaminants in in the aquatic 8
environment
1.5.1 Liquid/Liquid extraction 8
1.5.2 Solid phase extraction 8
1.5.3 Other extraction techniques 11
1.6 Passive Sampling 12
1.6.1 Passive sampling devices for organic compounds 16
1.6.1.1 The semi-permeable membrane device (SPMD) 16
1.6.1.2 The silicon rubber or polydimethylsiloxane sampler 18
1.6.1.3 The polar organic chemical integrative sampler (POCIS) 19
1.6.1.3.1 Types of sorbent used with POCIS 21
iv
1.6.1.4 The Chemcatcher® 23
1.6.1.4.1 Non-polar Chemcatcher® 24
1.6.1.4.2 Polar Chemcatcher® 26
1.6.1.5 Other types of passive sampler for organic compounds 35
1.6.2 Uptake of analytes by passive samplers and determination 36
of aqueous TWA concentrations compounds
1.7 Analytical separations and detection techniques 38
1.7.1 One-dimensional gas chromatography 38
1.7.2 Multi-dimensional gas chromatography 44
1.7.3 Comprehensive two-dimensional gas chromatography (GCxGC) 44
1.7.3.1 Enabling GCxGC capability with existing GC 46
chromatographs
1.7.3.2 Coupling of GCxGC to time-of-flight mass 47
spectrometry (GCxGC TOF-MS)
1.7.3.3 Comprehensive GCxGC and low energy or soft 55
electron ionisation
1.7.3.4 Soft ionisation techniques 56
1.7.3.5 Chemical ionisation 57
1.7.3.6 Supersonic molecular beams (SMB) and soft cold EI 58
1.7.3.7 Variable electron ionisation source 63
1.7.4 High Performance Liquid Chromatography (HPLC) 65
1.7.4.1 HPLC with high resolution mass spectrometry 67
(HPLC HRMS)
1.7.4.2 Matrix effects 69
1.7.4.3 TOF and Orbitrap mass spectrometric detectors 70
v
1.7.4.4 LC HRMS libraries and databases for organic 72
pollutants in water
1.7.4.5 Data independent MS/MS acquisition 75
1.7.5 Retention time prediction 76
1.8 Conclusions from the literature review 81
1.9 Aims and objectives 84

Chapter 2 86
Identification of pollutants in non-polar passive sampling devices using
comprehensive two-dimensional gas chromatography and variable energy
electron ionisation time-of-flight mass spectrometry

2.1 Introduction 87
2.2 Aims and objectives 89
2.3 Experimental 90
2.3.1 Reagents and standards 90
2.3.2 Deployment of SPMDs 93
2.3.3 Extraction of SPMDs 95
2.3.4 Conventional one-dimension GC analysis (experimental conditions) 97
2.3.5 GCxGC TOF-MS analysis (experimental conditions) 98
2.3.6 GCxGC TOF-MS analysis with Select eV (experimental conditions) 99
2.4 Results and discussion 101
2.4.1 Compounds identified from conventional one dimensional GC 101
analysis
2.4.2 Deconvolution 112
2.4.3 Comprehensive GCxGC analysis 112
2.4.4 Pesticides identified with GCxGC analysis 112
vi
2.4.5 PAHs identified with GCxGC analysis 122
2.4.6 PCB analysis 132
2.4.7 Emerging contaminants 140
2.4.7.1 Polycyclic musks, UV sunscreen filters and phosphate fire 140
retardants
2.4.8 Variable energy electron ionisation 145
2.4.8.1 Molecular ion intensity and signal-to-noise ratio 145
improvements for the molecular ions of pesticides
2.4.8.2 Signal-to-noise ratio improvements for the molecular 151
ions of emerging contaminants
2.4.8.3 Reduced spectral ‘noise’ 157
2.5 Conclusions 157

Chapter 3 160
Development of a novel ‘all ions’ MS/MS screening method for the reliable
identification of pharmaceuticals in polar passive sampler extracts

3.1 Introduction 161
3.2 Aims and objectives 163
3.3 ‘All ions’ MS/MS 163
3.3.1 Find by formula algorithm 168
3.3.2 Formation of the database 168
3.4 Experimental 177
3.4.1 Reagents and reference materials 177
3.4.2 Intermediate and working standard solution mixes 179
3.4.3 Preparation of the mobile phase for LC Q-TOF-MS analysis 179
3.4.4 Preparation of POCIS samplers 179
vii
3.4.4.1 Preparation and cleaning of membranes for POCIS 179
3.4.4.2 Cleaning of the OASIS HLB phase sorbent 180
3.4.4.3 Assembly of POCIS samplers 181
3.4.5 Cleaning of the Chemcatcher® bodies, rings and transport caps 183
3.4.6 Conditioning of the HLB-L disks for the polar Chemcatcher® 183
3.4.7 Preparation of membranes for of the Chemcatcher® 184
3.4.8 Chemcatcher® assembly 184
3.4.9 Deployment of the samplers at the waste water treatment plant 185
3.4.10 Extraction of POCIS samplers 185
3.4.11 Extraction of HLB-L disks from the Chemcatcher® samplers 190
3.4.12 Creation of the searchable database using the Agilent personal 193
compound database and library (PCDL) software
3.4.13 LC Q-TOF-MS analysis 201
3.4.14 Data analysis 204
3.4.15 Waste water treatment plants chosen for the deployments 205
3.5 Results and discussion 206
3.5.1 Identification of pharmaceuticals in MS scan mode 206
3.5.2 Peak area responses for the cardiovascular drugs at the 207
Carmarthen and Llanelli waste water treatment plants
3.5.3 Identification of pharmaceuticals using the ‘all ions’ MS/MS 208
technique
3.5.4 Mass accuracy 211
3.6 Conclusions 230

viii
Chapter 4 232
Comparison of the sampling efficiency of two passive samplers for organic
compounds in effluents: Polar Chemcatcher® versus the polar organic chemical
integrative sampler (POCIS)

4.1 Introduction 233
4.2 Aims and objectives 234
4.3 Experimental 235
4.3.1 Data acquisition and analysis 235
4.3.2 LC Q-TOF-MS analysis 235
4.3.3 Peak extraction of targeted pharmaceuticals 236
4.3.4 Feature finding and peak extraction of untargeted features 239
4.3.5 Correction of peak areas obtained from POCIS devices 243
4.3.6 Mass profiling of ‘unknowns’ present in Chemcatcher® 247
and POCIS samplers
4.4 Results and discussion 248
4.4.1 Comparison of uptakes of 68 pharmaceuticals by Chemcatcher® 254
and POCIS
4.4.2 Analysis of variance of pharmaceuticals identified in 255
co-deployments undertaken at the Gowerton site
4.4.3 Least squares and orthogonal regression analysis of the 258
averaged pharmaceutical Chemcatcher® and POCIS data
4.4.4 Statistical analysis of ‘unknown’ features or peaks 264
4.4.5 Comparison of uptakes of ‘unknown’ compounds by 265
Chemcatcher® and POCIS
4.4.6 Analysis of variance of ‘unknowns’ identified in co-deployments 267
undertaken at the Gowerton WWTP
ix
4.4.7 Least squares and orthogonal regression analysis of the 269
‘unknowns’ data obtained from all replicates of Chemcatcher®
and POCIS
4.4.8 Least squares and orthogonal regression analysis of the averaged 274
‘unknowns’ data obtained from Chemcatcher® and POCIS
4.4.9 Mass and retention time profiling of the polar passive sampler 281
extracts
4.5 Conclusions 294

Chapter 5 296
In-silico prediction of liquid chromatographic retention times to aid in the
identification of unknown or suspect compounds

5.1 Introduction 297
5.2 Aims and objectives 298
5.3 Experimental 298
5.3.1 Reagents and standards 298
5.3.2 LC Q-TOF-MS analysis 299
5.3.3 Formation of database 300
5.4 Results and discussion 302
5.4.1 The correlation plot obtained from the ‘training set’ of compounds 302
5.4.2 Retention time prediction from the testing set of compounds 303
5.4.3 Comparison of chromatographic similarity between regression 313
plots
5.4.4 The effects of matrix on measured retention times in passive 316
sampling extracts

x