Method for internal standard introduction for quantitative analysis using on-line solid-phase extraction LC-MS/MS

A novel approach for on-line introduction of internal standard (IS) for quantitative analysis using LC-MS/MS has been developed. In this approach, analyte and IS are introduced into the sample injection loop in different steps. Analyte is introduced into the injection loop using a conventional autosampler (injector) needle pickup from a sample vial. IS is introduced into the sample injection loop on-line from a microreservoir containing the IS solution using the autosampler. As a result, both analyte and IS are contained in the sample loop prior to the injection into the column. Methodology allowed to reliably introduce IS and demonstrated injection accuracy and precision comparable to those obtained using off-line IS introduction (i.e., IS and analyte are premixed before injection) while maintaining chromatographic parameters (i.e., analyte and IS elution time and peak width). This new technique was applied for direct analysis of model compounds in rat plasma using on-line solid-phase extraction (SPE) LC-MS/MS quantification. In combination with on-line SPE, IS serves as a surrogate IS and compensates for signal variations attributed to sample preparation and instrumentation factors including signal suppression. The assays yielded accuracy (85-119%), precision (2-16%), and analyte recovery comparable to those obtained using off-line IS introduction. Furthermore, on-line IS introduction allows for nonvolumetric sample (plasma) collection and direct analysis without the need of measuring and aliquoting a fixed sample volume prior to the on-line SPE LC-MS/MS analysis. Therefore, this methodology enables direct sample (plasma) analysis without any sample manipulation and preparation.     

激光扫描显微镜中的扫描系统

叙述了扫描系统在激光扫描显微镜中的作用,扫描器的位置调整。推导出由于扫描器位置的变化而引起的光程变化,提出了机械设计要求。     

Ontology-based reconfiguration agent for intelligent mechatronic systems in flexible manufacturing

This paper proposes a novel approach to achieving fast reconfiguration of modular manufacturing systems, based on an ontology-based reconfiguration agent. The agent uses ontological knowledge of the manufacturing environment for the purpose of reconfiguration without human intervention. The current mass customization era requires increased flexibility and agility in the manufacturing systems to adapt changes in manufacturing requirements and environments. Our configuration agent minimises the overheads of the current reconfiguration process by automating it. It infers facts about the manufacturing environment from the ontological knowledge model and then decides whether the current environment can support the given manufacturing requirements. This paper proposes the agent architecture enabling the integration between the high level planning with the distributed low level control compliant with the upcoming IEC 61499 function blocks standard.