Novel separation strategies in industrial and environmental analysis

This thesis is a study into the application of separation techniques to the analysis of both industrial and environmental sample matrices. Chapter 1 is a literature survey into the background of adhesives (both anaerobic and cyanoacrylic adhesives). The literature survey also details the composition of adhesives and their analysis. Chapter 2 details an analytical study into the decomposition of the key reducing agents found in anaerobic adhesives, including acetyl phenylhydrazine, tetrahydroquinoline, dimethyl-/?-toluidine and (p-toluene suphonyl) hydrazine. A suitable HPLC separation system was developed, which was then used to monitor any decomposition of the reducing agents. Investigation of the above was carried out in the presence of saccharin, maleic acid and cumene hydroperoxide (both in the presence and absence of the transition metals, copper and iron). Comparison of the rates of decomposition of the reducing agents revealed some information into the role of the acids and peroxide in the overall reaction mechanism. The products produced as a result of these reactions were also identified using preparative TLC and techniques such as IR, NMR and mass spectrometry. Chapter 3 details the development of a suitable method of anion separation using capillary electrophoresis. A suitable extraction technique was also developed which could extract the anions from the adhesive mixture (both crude and distilled preparations), into an aqueous medium. The method developed was amenable to the analysis of the full range of cyanoacrylate adhesive mixtures (methyl-, ethyl-, butyland methoxy ethyl-cyanoacrylates). Chapter 4 involved the development of an electrochemical system that was capable of detecting microcystins. The work also involved HPLC mobile phase optimisation, microcystin purification and microcystin extraction (both from ‘pure bacterial cultures’ and field samples). An electrochemical detector was developed which was capable of detecting microcystins, it was also capable of detecting other polypeptides (found in partially purified microcystins) which were not detected using UV detection. The main problem encountered was the detection of the microcystins in field samples as other proteins found in field samples were also electrochemically active. Conclusions drawn from the work carried out in the thesis, and suggestions for future research are outlined in Chapter 5

An investigation into the sample preparation procedure and analysis of cyanoacrylate adhesives using capillary electrophoresis

In this study, the trace acid profile of cyanoacrylate adhesives was studied using capillary electrophoresis. Liquid–liquid extraction was employed as the sample preparation step before separation by capillary electrophoresis. The solubility of the adhesives was investigated using various organic solvents, e.g. hexane and dichloromethane, and chloroform was determined to be the optimum solvent as it enabled the full dissolution of the adhesive. A comprehensive stability study was performed over a 3-year period and results indicate that the adhesives were stable for 2 years after which their stability and performance degraded

Priorities for synthesis research in ecology and environmental science

ACKNOWLEDGMENTS We thank the National Science Foundation grant #1940692 for financial support for this workshop, and the National Center for Ecological Analysis and Synthesis (NCEAS) and its staff for logistical support.Peer reviewedPublisher PD

Priorities for synthesis research in ecology and environmental science

ACKNOWLEDGMENTS We thank the National Science Foundation grant #1940692 for financial support for this workshop, and the National Center for Ecological Analysis and Synthesis (NCEAS) and its staff for logistical support.Peer reviewedPublisher PD

Rehabilitation versus surgical reconstruction for non-acute anterior cruciate ligament injury (ACL SNNAP): a pragmatic randomised controlled trial

BackgroundAnterior cruciate ligament (ACL) rupture is a common debilitating injury that can cause instability of the knee. We aimed to investigate the best management strategy between reconstructive surgery and non-surgical treatment for patients with a non-acute ACL injury and persistent symptoms of instability.MethodsWe did a pragmatic, multicentre, superiority, randomised controlled trial in 29 secondary care National Health Service orthopaedic units in the UK. Patients with symptomatic knee problems (instability) consistent with an ACL injury were eligible. We excluded patients with meniscal pathology with characteristics that indicate immediate surgery. Patients were randomly assigned (1:1) by computer to either surgery (reconstruction) or rehabilitation (physiotherapy but with subsequent reconstruction permitted if instability persisted after treatment), stratified by site and baseline Knee Injury and Osteoarthritis Outcome Score—4 domain version (KOOS4). This management design represented normal practice. The primary outcome was KOOS4 at 18 months after randomisation. The principal analyses were intention-to-treat based, with KOOS4 results analysed using linear regression. This trial is registered with ISRCTN, ISRCTN10110685, and ClinicalTrials.gov, NCT02980367.FindingsBetween Feb 1, 2017, and April 12, 2020, we recruited 316 patients. 156 (49%) participants were randomly assigned to the surgical reconstruction group and 160 (51%) to the rehabilitation group. Mean KOOS4 at 18 months was 73·0 (SD 18·3) in the surgical group and 64·6 (21·6) in the rehabilitation group. The adjusted mean difference was 7·9 (95% CI 2·5–13·2; p=0·0053) in favour of surgical management. 65 (41%) of 160 patients allocated to rehabilitation underwent subsequent surgery according to protocol within 18 months. 43 (28%) of 156 patients allocated to surgery did not receive their allocated treatment. We found no differences between groups in the proportion of intervention-related complications.InterpretationSurgical reconstruction as a management strategy for patients with non-acute ACL injury with persistent symptoms of instability was clinically superior and more cost-effective in comparison with rehabilitation management

Novel separation strategies in industrial and environmental analysis

This thesis is a study into the application of separation techniques to the analysis of both industrial and environmental sample matrices. Chapter 1 is a literature survey into the background of adhesives (both anaerobic and cyanoacrylic adhesives). The literature survey also details the composition of adhesives and their analysis. Chapter 2 details an analytical study into the decomposition of the key reducing agents found in anaerobic adhesives, including acetyl phenylhydrazine, tetrahydroquinoline, dimethyl-/?-toluidine and (p-toluene suphonyl) hydrazine. A suitable HPLC separation system was developed, which was then used to monitor any decomposition of the reducing agents. Investigation of the above was carried out in the presence of saccharin, maleic acid and cumene hydroperoxide (both in the presence and absence of the transition metals, copper and iron). Comparison of the rates of decomposition of the reducing agents revealed some information into the role of the acids and peroxide in the overall reaction mechanism. The products produced as a result of these reactions were also identified using preparative TLC and techniques such as IR, NMR and mass spectrometry. Chapter 3 details the development of a suitable method of anion separation using capillary electrophoresis. A suitable extraction technique was also developed which could extract the anions from the adhesive mixture (both crude and distilled preparations), into an aqueous medium. The method developed was amenable to the analysis of the full range of cyanoacrylate adhesive mixtures (methyl-, ethyl-, butyland methoxy ethyl-cyanoacrylates). Chapter 4 involved the development of an electrochemical system that was capable of detecting microcystins. The work also involved HPLC mobile phase optimisation, microcystin purification and microcystin extraction (both from ‘pure bacterial cultures’ and field samples). An electrochemical detector was developed which was capable of detecting microcystins, it was also capable of detecting other polypeptides (found in partially purified microcystins) which were not detected using UV detection. The main problem encountered was the detection of the microcystins in field samples as other proteins found in field samples were also electrochemically active. Conclusions drawn from the work carried out in the thesis, and suggestions for future research are outlined in Chapter 5