Instrument, autosampler flexibility

Four serial (RS232) ports are provided for flexible communications to other instruments, i.e. autosamplers. In addition, five analogue inputs, tvsro analogue outputs and 3 TTL input/outputs are provided to ensure complete flexibility. These allow auxihary instruments under direct control and the abihty to process data generated by these in real time. These features extend the range of facihties on these expensive but worthwhile analytical techniques. There is no doubt that future developments in computing will continue to have a radical impact on these instrumental systems. 

Three approaches to the automation process can be distinguished, taking into account the criterion of the flexibility of the automation device [2], The first, denoted as flexible, is characterized by the possibility of adaptation of the instruments to new and varying demands required from the laboratory examples of these instruments are robots. The second approach, denoted as semiflexible, involves some restrictions for the tasks executed by the instrument the tasks are controlled by a computer program and its menu. As examples, autosamplers or robots of limited moves can be given. In the third approach, the instruments can execute one or two tasks, without feasibility of new requirements as examples, supercritical fluid extractors or equipment for dissolution of samples can be given. 

Since the advent of hyphenated MS techniques, gas chromatography (GC)-MS in the 1980s and LC-MS in the 1990s autosamplers have become a necessity at the front of MS-based instrument systems. Indeed the autosampler is a critical component of any modem LC-MS-based analysis system. Autosamplers have evolved to meet the increased demand requirements of automated well-based MS analysis. The primary figures of merit for autosampling devices are robustness, speed, lack of memory effect, swept volume, plate capacity, integration with MS software, and flexibility ... 

System volume is one of the parameters that instrument manufacturers have striven to reduce when the engineering of UHPLC systems began. Some reductions were simple. In others, for instance, in autosamplers, the volume reduction was more complicated. For this reason, total system volumes are not uniform across all available instrumentation. Some manufacturers strictly define their system volume, and the qualification of the instruments for use in regulated environments hinges on this volume being fixed. Other manufacturers offer more flexible options. Virtually all UHPLC systems are modular and can have different components (column switcher vs. single column, binary pump vs. quaternary pump, multiple detectors), and for some manufacturers, two systems may have the same components but be plumbed differently. All of these configurations have an effect on the system volume. Because some of the benefits of UHPLC are the speed of analysis, sharpness of the peaks, and retention of resolution, extra dead volume is undesirable, as it reduces these benefits. To ease method transfer problems, one must account for these types of differences. 

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