Sample Application

The most common method of application, and that most suited to MS applications when MS analysis is to be straight from the adsorbent, is by a glass capillary as a spot ('spotting'). For single MS

experiments a single spot is usually sufficient. Where multi-MS experiments are to be performed, such as when tandem mass spectrometry is to be used, the application of a row of replicate spots is the preferred method, the separated analytes from a fresh spot being used as those from a previous one become exhausted. If the analytes are to be removed from the adsorbent before analysis by MS the application of a short line ('streaking') has been found to be the best method. Whether the spotting or streaking method is used, care is needed during application to keep the analyte origin as compact as possible. A sample that is too large causes poor-quality separations due to the analyte diffusing and causing the spot to broaden. Quantities of sample spotted are in the range of 1-50 |g ijl-1, 1-10 |L being applied to the plate by multiloading a 1-5 |L capillary.

Care has to be taken not to damage the surface of the adsorbent as this causes the mobile phase to elute unevenly, resulting in distorted spots and so leading to a loss of chromatographic resolution. The type of matrices being studied and the detection limit of the mass spectrometer are then the critical factors in determining to what extent analysis is possible. However, when sample loading needs to be high, the deconvolution-by-mass capabilities of the mass spectrometer often compensate for the reduction in resolution.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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