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A miniature mass spectrometer (MMS) is a type of mass spectrometer (MS) which has small size and weight and can be understood as a portable or handheld device. On the other hand, a lab-scale mass spectrometer weighs hundreds pounds and costs from a few hundreds thousands to a million dollars. One of the purposes of producing MMS is for in situ analysis or to bring the lab to the sample with simple operation so that non-professional personnel like physicians at the bedside, firefighters in a burning factory, food safety inspectors in a warehouse or at the airport checkpoints etc. can use at ease with cheaper cost. Although, reducing the size of MS leads to a poorer performance of a MS, MMS is designed to maintain a sufficient resolutions, detection limits, accuracy and especially the capability of automatic operation which are suitable for most of the specific task applications. ==Coupling and ionization in miniature mass spectrometer== In typical mass spectrometry, MS is coupled with separation tools like gas chromatography, liquid chromatography or electrophoresis to reduce the effect of the matrix or background and improve the selectivity especially when the analytes are widely different in concentration. Sample preparation including sample collection, extraction, pre-separation increases the size of the mass analysis system and adds time and sophistication to the analysis. A lot of contribution promotes miniaturizing devices and simplifying the operations. A micro-GC has been implemented to fit to a portable MS system. Besides microfluidics is a competent candidate for MMS and automating sample preparation. In this technique, most of the steps for sample preparation are staged similarly with laboratory systems, but miniature chip-based devices are used with low consumption of sample and solvents. On way to circumvent classical, lab-based sample introduction systems is the use of ambient ionization as it does not require mechanical or electrical coupling to a MMS and can generate ions in the open atmosphere without prior sample preparation. Different ambient ionization methods, including low-temperature plasma, paper spray, and extraction spray, have been demonstrated to be highly compatible with MMS. Without separation coupling, the basic building blocks in MMS, which are similar in composition with the conventional laboratory counterpart, are sample inlet, ionization source, mass anlayzers, detector, vacuum system, instrument control and data acquisition system. Three most important components in MMS contributing to miniaturization are mass analyzer, vacuum system and electronics control system. Reducing the size of any components is beneficial to the miniaturization. However, it is noticeable that minimizing the analyzer’s size can greatly enhance the miniaturization of the other components especially the vacuum system because the analyzer is the pressure deciding factor for MS analysis and pressure interface fabrication. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Miniature mass spectrometer」の詳細全文を読む スポンサード リンク
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