Tedlar™ bags are a promising medium for remote breath collection and later analysis using SIFT-MS for disease diagnosis. It is important to understand the changes in integrity of samples stored in Tedlar™ bags. However, there is little work into this problem completed to date, and thus little known about these issues. Therefore, a study into the integrity of samples stored in Tedlar™ bags and analysed using SIFT-MS was undertaken. The sample integrity of ammonia, acetone, ethanol, isoprene and pentane, all initially at 3ppm in breath and nitrogen substrates, and stored in Tedlar™ bags was investigated. Experiments tested the effect of storage size (0.5, 1, 3L), storage time (6-48 hours), storage temperature (23℃ - 25℃, 37℃), humidity (0.4 - 4.5% absolute) and inter-bag variation using triplicate bags. The SIFT-MS instrument used was LDI2 located at Christchurch Hospital. The repeatability and precision of LDI2 was established using prepared cylinder samples (0.05% absolute humidity) of acetone, pentane and ethanol tested at seven times over a 250 min time period. A generalised Cauchy distribution was used to give a combined distribution from multiple bags for the sample humidity and compound concentration. A combined measure of the repeatability and precision, T s , ranged between 217 - 349 ppb for ethanol, acetone and pentane. The factors affecting the repeatability and precision were both machine and compound dependant. The effect of the factors differed over time, with different precursors and compounds. No obvious effects of bag storage size on the sample integrity of pentane, isoprene, ethanol and acetone were observed. The absolute humidity change within bag samples was linked to the volume to surface area ratio because it was more affected by permeation and condensation. All compounds in the nitrogen substrate (except for 37℃ stored acetone (NO+)) displayed decreases in sample integrity with time. All compounds in the breath substrate displayed regular losses of sample integrity, except for the 37℃ and 23℃ - 25℃ stored ethanol (NO+) and 37℃ stored ethanol (H3O+), pentane (O2+) and ammonia (H3O+, O2+). The average change of sample integrity for pentane, isoprene, ethanol and acetone ranged from 0.2 to 3.6 times the maximum T s , while ammonia ranged from 0.9 - 10 times. All observed behaviour was reproducible. Absolute humidity and storage temperature affected the sample integrity of acetone, ethanol and ammonia. Generally, the intra-bag variance was comparable between all storage temperatures and substrates while the inter-bag variation was affected by the absolute humidity. Only the initial and final concentrations between precursors for the 23℃ - 25℃ stored breath and nitrogen substrates agreed. The breath substrate samples gave erroneous values for ammonia. Permeation of compounds into the bags from the atmosphere was not significant. The overall issues surrounding storing breath in Tedlar™ bags for analysis using SIFTMS is not the loss of sample integrity, but the kinetics, precision and repeatability of the SIFT-MS instrument. The current kinetics are not adequate to accurately monitor acetone, isoprene, pentane, ammonia and ethanol in breath and stored in Tedlar™ bags at breath absolute humidity levels greater than 3%. Generally, the loss of sample integrity was only marginally outside the repeatability and precision of the machine.

The aim of this study is to optimize the storage and shipping processes of Plasma Separation Cards (PSC) by developing a novel prototype designed to reduce manual labore and ensure sample integrity. An experimental design was employed to address current limitations in PSC handling. These limitations include labor-intensive processes and potential sample degradation. In this approach rigorous testing was done to evaluate the prototype's performance in various environments and different materials. The research in this study include lab testing of samples stored in the prototype, assessment of different storage conditions and analysis of shipping processes. The main research question was: “How can a prototype for PSC storage be optimized to reduce manual labor in PSC handling while ensuring sample integrity during storage and shipping?”. To answer this question the prototype was tested for its effectiveness in reducing storage space and facilitating automated handling The findings of this study show that the prototype that was created can significantly reduce the required storage space while still being usable by liquid handling robots. During the study it was noted that minor misalignment issues were present due to the limitations of the type of 3D printers used. These issues could be addressed with more precise printing technologies such as Stereolithography (SLA) or Selective Laser Sintering (SLS). Both materials used in this study, PLA (Polylactic acid) and PETG (Polyethylene Terephthalate Glycol) materials were found suitable for storing PSC samples under most conditions. However, the measurements for the samples with PLA indicated limitations at 65 °C under certain conditions, making PETG a safer choice under higher temperature. The study contributes to the field by providing an innovating solution for PSC sampling that is scalable. This enhances the possibility for remote monitoring end predictive diagnostics. The prototype indicates a promising direction for future research and application and medical diagnostics by improving operational efficiency while aligning with sustainability goals. This study explores the following aspects: sample handling, storage and shipping. The practical implication includes reduced manual labor, minimized human error and increased efficiency for these aspects.