Mass spectrometers interfaceable manufacturers

The direct-liquid-introduction (DLI) interface was made available commercially just after the moving-belt interface to which, as no company produced both types, it was an alternative. At this time, therefore, the commercial LC-MS interface used within a laboratory was dictated by the manufacturer of the mass spectrometer already in use unless a new instrument was being purchased solely for LC-MS applications. The development of LC-MS in the early 1980s was such that this was very rare and it was therefore unusual that a scientific evaluation was carried out to assess the ability of a type of interface to solve problems within a particular laboratory. 

The fact that moving-belt interfaces were not offered as accessories by all of the major manufacturers of mass spectrometers, plus the fact that these interfaces could not be easily constructed within the laboratories where the technique... 

GC-C-IRMS was first demonstrated by Matthews and Hayes (1978). However, it was somewhat later that Barrie and others (Barrie et al., 1984) coupled a GC, via a combustion interface, to a dual collector mass spectrometer to produce the forerunner of today s GC-C-IRMS instruments. Even so, true determinations of 815N values of individual compounds by GC-C-IRMS remained elusive until finally demonstrated by Hayes and co-workers (Merritt and Hayes, 1994). More recently the precision of GC-C-IRMS instruments has been improved further still with uncertainties in 813C values as small as 0.5 %o for samples containing 5 pmol C and 0.1 %o for 100 pmol samples having been demonstrated (Merritt and Hayes 1994). Instruments available commercially today, from several manufacturers, all conform to the same general principles of design. 

The thermospray interface overcame many of the problems encountered with the moving-belt and direct-liquid-introduction interfaces and with the advent of this, LC-MS became a routine analytical tool in a large number of laboratories. This was reflected in the fact that this was the first type of interface made available commercially by the majority of the manufacturers of mass spectrometers. 

With the column blank in place, we are ready to do a general system cleaning. The technique is called pacification. It involves washing the system with 20% nitric acid. It sounds harsh and is, but your system should be resistant to it. Check with your manual to ensure that all wetted surfaces are stainless steel, ruby, Teflon , and quartz. If you can t tell from the manual, call the manufacturer. Use pacification only with UV detectors, I can t guarantee other detectors will be resistant. Do not use pacification on mass spectrometers or their interfaces ... 

The evolution of the ESI source has been marked by the use of electrospray devices as interfaces between the separation systems such as HPLC or CE and MS detectors, the earliest instances of which were reported by Yamashita and Fenn [59] and Aleksandrov et al. [60] in the mid-1980s. Because ESI-MS is used in many areas of chemistry, a vast number of articles reporting specific modifications of the electrospray interface has been published so far. Also, instrument manufacturers have provided innovative solutions for more sensitive and reliable mass spectrometers. 

Because of the variety of interfaces and the low detection limits, hyphenated mass spectrometers are among of the fastest growing markets for scientific instrument manufacturers in the 1990s and beyond. Every available type of chromatographic separation has been analyzed by mass spectrometry from desorption methods for TLC plates26 to online CE-MS.27,28 Not all techniques are routinely used for the characterization of small organic molecules of pharmaceutical interest (Table 4). The two workhorse instruments for the characterization of small molecules are GC-MS and... 

Fig. 5.3 Overview of commercial instrument, lA-Lab (model L-250G-IA, manufactured by Canon Anelva, Kanagawa, JAPAN). This equipment consists of direct inlet probe (DIP), Li+ attachment reaction chamber with LP emitter in it, the ion focusing system, and the quadrupole mass spectrometer. Li+ is supplied by a Li+ emitter. There are two types of interface for sample introduction an introduction tube for gases and a direct inlet probe for solids and liquids. ( 2009, Canon Anelva, Data sheet)...

Any technique for gas analysis can be applied to EGA. The most frequently used methods are mass spectroscopy (MS) and Fourier transform infrared spectroscopy (FTIR). Many instrument manufacturers provide the ability to interface their TGAs with MS or FTIR (see Section 3.7, on instrumentation). Temporal resolution between the TGA and the MS or FTIR detector is an important feature, for example, in distinguishing absorbed water from water as a reaction product and in assigning a decomposition product to a specific mass loss. Each method has its experimental requirements, limitations, and advantages. Mass spectroscopy is a very sensitive technique that identifies volatile species by their mass-to-charge ratio, referred to as m/z. The evolution of the sum of all mJz species can be plotted and compared with the derivative TGA plot to ensure temporal resolution between the TGA and the mass spectrometer. The evolution of a specific mJz, associated with species such as water or formaldehyde, can show the distinct evolution of these compounds. The most common ionization is by 70eV electron impact (El), which operates... 

In this section we briefly review commercial thermogravimetric analyzers in alphabetical order of manufacturer. Please visit the respective supplier Websites for current offerings and more information. See Section 3.2.1 for descriptions of balance configurations. While most suppliers offer autostep-wise software to control the furnace temperature (see Fig. 3.40), kinetics software such as the ASTM El 641 Flynn-Wall method described in Section 3.5.5, and the ability to interface to a Fourier transform infrared spectrometer (FTIR) or mass spectrometer (MS), the reader interested in these applications is advised to confirm the features of particular TGA systems. 

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