The direct sampling of analytes from surfaces under atmospheric conditions followed by mass spectrometric analysis is an ever expanding area of scientific research. Atmospheric pressure surface sampling and ionization techniques for mass spectrometry (MS) offer the ability to interrogate samples that could not be studied under vacuum conditions required of more traditional MS surface analysis techniques. The geometry and nature of materials or surfaces that can be analyzed has been greatly expanded as a result. This dissertation characterizes and shows applications of liquid microjunction surface sampling probe (LMJ-SSP) electrospray ionization systems. The presented work compares traditional analytical work flows with novel analytical workflows utilizing LMJ-SSP-MS technology. The increase of throughput and/or chemical information without the sacrifice of analytical figures of merit is shown and discussed. The readout of analytical surfaces; surfaces where analyte has ended up on a surface in a traditional work flow and not just placed there, constitutes the focus of what is presented in the preceding work. Finally the prospects for spatial liquid chromatography-mass spectrometry (LC-MS) as a powerful analytical technology „in wait‟ is discussed and supported by the presented data.

The primary step in the microbiological assessment of highly dynamic and complex food processing conditions is environmental sampling. The objectives of this study were to: (1) compare the efficacy of four sampling devices including Microbial-Vac system (MV), cellulose sponge (SP), polyester swab (SW) and composite tissue (CT), for the recovery of Listeria monocytogenes and Brochothrix thermosphacta on five surfaces and (2) to determine if there was a significant difference between the recovery of low (10 CFU/900cm2) and high (100 CFU/900cm2) L. monocytogenes inoculum levels using the sampling devices in a simulated food processing environment. Surfaces used for this study were stainless steel (SS), polyethylene cutting board (CB), polyurethane conveyor belt (PB), open hinge flat top conveyor belt (FT) and mesh conveyor belt (MB). Food contact surfaces were inoculated with L. monocytogenes to obtain a final cell population of 10 (low) or 100 (high) CFU/900 cm2. An average cell density of 10,000 CFU/25 cm2 was used for inoculating B. thermosphacta on each of the surfaces. Inoculated surfaces were dried and held for two hours at 4˚C then sampled and processed for detection. Because L. monocytogenes is a "zero tolerance" pathogen in ready-to-eat foods, the qualitative analysis included an enrichment step to detect presence/absence in the sample. In comparison, B. thermosphacta was directly plated in order to quantify the recovery capability of each device. Results indicated for recovery of 100 CFU/900 cm2 L. monocytogenes, there was no difference among devices on SS, CB or PB surfaces (p>0.05). However, a significant difference was detected at 10 CFU/900 cm2 on SS between MV and CT, 62.97 and 17.34%, respectively (p=0.0086). Results for FT indicated MV was superior over SP and SW (p=0.0004) for detection of high and low L. monocytogenes. There was no difference for the quantitative recovery of B. thermosphacta on PB and SS; however, there was a difference (p=0.0371) among devices on CB indicating MV was superior over SP and CT. The swab recovered 3.25 log CFU/25cm2 from flat top belts and was significantly lower (p=0.0259) than MV and SP devices, 4.29 and 4.12 log CFU/25cm2, respectively.

Motivation: The health effects of platinum on the human body are a great concern. It affects the respiratory system as well as the skin. The demands for platinum have seemingly increased over the last few years due to its use in automobile exhaust gas catalysts. Thus there will be an increase in the production and processing of platinum and therefore a greater possibility of exposure to platinum compounds. This is why it is of great importance to evaluate the surface sampling methods, to ensure that they are effective for platinum use. Objectives: 1) To evaluate and compare a few different surface sampling methods for removal of platinum salts from contaminated surfaces in order to determine which one of these methods has the best retention and recovery efficiency. 2) To use the most effective method to monitor surface contamination on porous and non–porous surfaces in a platinum refinery. Methods: Two types of filters (mixed cellulose ester and polyvinyl chloride) and GhostwipesTM were evaluated and compared in this study. Platinum solution (hexachloroplatinic acid) concentrations of 50, 150 and 300 ug Pt/ml solution were used. The retention efficiency of the different sampling mediums was tested by releasing 1 ml of each concentration directly onto the sampling medium. Efficiencies were tested on a non–porous (glass) and porous surface (semi–face bricks). This was done to see how the collection efficiency of the medium will differ on these two surfaces. A total of three wipes were used per surface, however were analyzed individually. All the samples were analyzed using the Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP–AES) analytical method by an accredited laboratory. Results: The results obtained indicated the retention and recovery efficiencies of the three sampling mediums at the three platinum concentrations of 50, 150 and 300 ug Pt/ml solutions. The retention efficiency of the GhostwipesTM was 93.2% at 50 ug Pt/ml solution, 95.3% at 150 ug Pt/ml solution and 93.6% at 300 ug Pt/ml solution, whilst the mixed cellulose ester (MCE) filters and polyvinyl chloride (PVC) filters were lower than 30% at all three concentrations. The overall recovery efficiencies of all three concentrations of the GhostwipesTM and MCE filter were the highest: the GhostwipesTM with levels of 73.9 %, 84.4% and 63.5% and the MCE filters with levels of 71.4%, 84.4% and 80.2%, whilst the PVC filters did not achieve levels above 60%. The wipe materials were also evaluated in terms of the ASTM E1792 standard requirements for wipe materials. Conclusion: GhostwipesTM were found to be the most suitable sampling medium based on retention and recovery efficiencies. The GhostwipesTM also complies with all the requirements listed in the ASTM E1792 standard for wipe materials, which makes it the most suitable wipe sampling material. The MCE and PVC filters however do not comply with all the ASTM E1792 requirements. / Thesis (M.Sc. (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2011.

Motivation: The health effects of platinum on the human body are a great concern. It affects the respiratory system as well as the skin. The demands for platinum have seemingly increased over the last few years due to its use in automobile exhaust gas catalysts. Thus there will be an increase in the production and processing of platinum and therefore a greater possibility of exposure to platinum compounds. This is why it is of great importance to evaluate the surface sampling methods, to ensure that they are effective for platinum use. Objectives: 1) To evaluate and compare a few different surface sampling methods for removal of platinum salts from contaminated surfaces in order to determine which one of these methods has the best retention and recovery efficiency. 2) To use the most effective method to monitor surface contamination on porous and non–porous surfaces in a platinum refinery. Methods: Two types of filters (mixed cellulose ester and polyvinyl chloride) and GhostwipesTM were evaluated and compared in this study. Platinum solution (hexachloroplatinic acid) concentrations of 50, 150 and 300 ug Pt/ml solution were used. The retention efficiency of the different sampling mediums was tested by releasing 1 ml of each concentration directly onto the sampling medium. Efficiencies were tested on a non–porous (glass) and porous surface (semi–face bricks). This was done to see how the collection efficiency of the medium will differ on these two surfaces. A total of three wipes were used per surface, however were analyzed individually. All the samples were analyzed using the Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP–AES) analytical method by an accredited laboratory. Results: The results obtained indicated the retention and recovery efficiencies of the three sampling mediums at the three platinum concentrations of 50, 150 and 300 ug Pt/ml solutions. The retention efficiency of the GhostwipesTM was 93.2% at 50 ug Pt/ml solution, 95.3% at 150 ug Pt/ml solution and 93.6% at 300 ug Pt/ml solution, whilst the mixed cellulose ester (MCE) filters and polyvinyl chloride (PVC) filters were lower than 30% at all three concentrations. The overall recovery efficiencies of all three concentrations of the GhostwipesTM and MCE filter were the highest: the GhostwipesTM with levels of 73.9 %, 84.4% and 63.5% and the MCE filters with levels of 71.4%, 84.4% and 80.2%, whilst the PVC filters did not achieve levels above 60%. The wipe materials were also evaluated in terms of the ASTM E1792 standard requirements for wipe materials. Conclusion: GhostwipesTM were found to be the most suitable sampling medium based on retention and recovery efficiencies. The GhostwipesTM also complies with all the requirements listed in the ASTM E1792 standard for wipe materials, which makes it the most suitable wipe sampling material. The MCE and PVC filters however do not comply with all the ASTM E1792 requirements. / Thesis (M.Sc. (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2011.

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Different sampling devices for paper spray - mass spectrometry (PS - MS) were investigated to improve the assay’s simplicity and sensitivity over traditional approaches. In the first one, pressure-sensitive adhesive paper was used as both sampling tool to collect drug residues on surfaces and paper substrate in PS - MS analysis. This method showed a significant improvement in drug collection on surfaces leading to low nano-gram level detection limits. Other sampling device being investigated was snap-in solid-phase extraction column, which demonstrated the ability to detect trace amounts of drugs in plasma while allowed easy transportation and the use of PS - MS automated system.