Ion trap detectors for

Campbell, C. The ion trap detector for gas Chromatography technology and application. Finnigan MAT IDT 15. 

Calibration of the ion-trap detector for quantification of tetrafluor-1.4 dicyanobenzene and 2,6 dichloro-4-nitroaniline. Finnigan MAT Application Data Sheet ADS 27. 

C. Campbell, The Ion Trap Detector for Gas Chromatography Technology and Application, Finnegan MAT IDT Publication 15. 

Specificity is unsurpassed. Traditionally, MS was performed on very large and expensive high-resolution sector instruments operated by experienced specialists. The introduction of low-resolution (1 amu), low-cost, bench-top mass spectrometers in the early 1980s provided analysts with a robust analytical tool with a more universal range of application. Two types of bench-top mass spectrometers have predominated the quadrupole or mass-selective detector (MSD) and the ion-trap detector (ITD). These instruments do not have to be operated by specialists and can be utilized routinely by residue analysts after limited training. The MSD is normally operated in the SIM mode to increase detection sensitivity, whereas the ITD is more suited to operate in the full-scan mode, as little or no increase in sensitivity is gained by using SIM. Both MSDs and ITDs are widely used in many laboratories for pesticide residue analyses, and the preferred choice of instrument can only be made after assessment of the performance for a particular application. 

As in the case in the analysis of food samples, the introduction of relatively inexpensive MS detectors for GC has had a substantial impact on the determination of methylxanthines by GC. For example, in 1990, Benchekroun published a paper in which a GC-MS method for the quantitation of tri-, di-, and monmethylxanthines and uric acid from hepatocyte incubation media was described.55 The method described allows for the measurement of the concentration of 14 methylxanthines and methyluric acid metabolites of methylxanthines. In other studies, GC-MS has also been used. Two examples from the recent literature are studies by Simek and Lartigue-Mattei, respectively.58 57 In the first case, GC-MS using an ion trap detector was used to provide confirmatory data to support a microbore HPLC technique. TMS derivatives of the compounds of interest were formed and separated on a 25 m DB-% column directly coupled to the ion trap detector. In the second example, allopurinol, oxypurinol, hypoxanthine, and xanthine were assayed simultaneously using GC-MS. 

The power of the system to overcome the problems associated with coeluting compounds is demonstrated in conjunction with the use of deuterated (or13C-labelled compounds) as internal standards. Such techniques could not be used in conventional gas chromatography as the deuterated compounds often co-elute, making quantification difficult if not impossible. With the ion-trap detector, however, it is easily possible to differentiate between the ions arising from the different compounds and the intensities of these ions could then be used for quantification of the compounds involved. The application of such techniques can be shown by... 

The signals from masses 292 and 326 characteristic of tetra- and pentachlorobiphenyl are shown in Fig. 1.6 (b,c). The specific detection mode of the ion-trap detector can be used to improve detection limits. This detector can monitor specific masses that are characteristic of compounds of interest. The detector records the signal for only those masses and ignores all others. Interference from other compounds is virtually eliminated with the Finnigan MAT 700 detector—up to 16 different groups of masses can be monitored or a mass range of up to 40 masses can be handled. With this flexibility it is possible to monitor only the masses of interest and to improve detection limits. 

Despite the difficulties of on-line automation, the need to develop such systems is considerable. The increase in the number of different compounds that must be determined and the number of samples required for a meaningful survey or laboratory study make it essential to improve the quality and throughput of samples. There are a number of stages in fully automating trace organic analysis. Autosampler LC or GC-data systems as GC-MS or GC-ion trap detector (ITD) are well established and require no further elaboration here [191, 203, 495]. 

Mass spectrometers used to be expensive and complex for routine use as a GC detector. The Ion Trap Detector (ITD, Finnigan) is a low priced mass spectrometer (MS) for capillary chromatography. Three analytical tools - SEC, GC, and ITD - are incorporated into a powerful analytical system for the analysis of complex mixtures such as coal liquids, petroleum crude and various refinery products. The instrumentation and the SEC-GC-MS analysis of a coal liquid are presented in this paper in order to demonstrate the technology. 

A Finnigan Ion Trap Detector (ITD), a small mass spectrometer for capillary chromatography, is the third detector interfaced with the gas chromatograph. The control of the ITD, the data collection, and the identification of species, by a library... 

The quadrupole MS detector was the first, and is still the most common, detector used for LC/MS, but a number of other mass spectrometers have been adapted to this application. Both three-dimensional spherical (ITD) and linear (LIT) ion trap detectors offer tremendous potential for general, inexpensive LC/MS systems. They both offer the ability to be used as either a mass spectral detector or as a MS/MS detector. The 3D ITD (Fig. 15.5) allows ions to be trapped in the ion trap where they can be fragmented by heavy gas collision and the fragments released by scanning the dc/RF frequency of the trap. 

Derivatization was conducted by the addition of a 10% H-ethyl-diiso-propylethylamine solution and a-bromo-2,3,4,5,6-pentafluorotoluene. Sample obtained from the derivatization procedure were dissolved in ethyl acetate prior to injection in splitless mode using a DB-1 capillary column. Helium was used as the mobile phase, and the injector temperature was set at 290 °C with a transfer line temperature of 270 °C. Sample detection used ion trap MS for detection, with the detector being set at negative chemical ionization with m/z = 262 (for CCA) and m/z = 286 (for the internal standard). The limit of quantitation was 5 ng/ml, and the average recovery ranged from 92.0% to 114%. In addition, the extraction efficiency ranged from 48.2% to 55.6% for concentrations of 5, 50, and 250 ng/ml. Samples were reported to be stable for up to 6 months when stored at 18 °C. 

The analytes separated on GC column are determined by a halogen-specific detector, such as an electrolytic conductivity detector (ELCD) or a microcoulo-metric detector. An ECD, FID, quadrupole mass selective detector, or ion trap detector (ITD) may also be used. A photoionization detector (PID) may also be used to determine unsaturated halogenated hydrocarbons such as chlorobenzene or trichloroethylene. Among the detectors, ELCD, PID, and ECD give a lower level of detection than FID or MS. The detector operating conditions for ELCD are listed below ... 

Orange, grapefruit, lemon Naringenin, hesperetin Peeling, separation for juice and albedo, air-dried, derivatization ID-BPX5 He GC/MS/ ion trap detector 36... 

GC peaks were identified using the Finnigan Ion Trap Detector (ITD) and its programs for libraiy comparison. To aid in the positive identification of peaks, a library of ITD mass spectra was generated using standards of compounds equivalent to those found in this work. Capillary GC (Perkin-Elmer Sigma-300) for the ITD was carried out similar to the conditions above, i.e., splitter ration, 20 1, oven temperature, 50 °C (5 minute hold) followed by a 5 C/min ramp to 180 C the 10 minute hold was followed by a 5 C/min ramp to 200 °C (20 minute hold to remove impurities). 

The gas chromatography analysis (Hewlett Packard 5890 with Perkin Elmer ion trap detector) of the soluble coke fractions for different reaction... 

Screening methods are available for analysis of benzene in feces and urine (Ghoos et al. 1994) and body fluids (Schuberth 1994). Both employ analysis by capillary GC with an ion trap detector (ITD). Benzene in urine has been determined by trapping benzene stripped from the urine on a Carbotrap tube, followed by thermal desorption GC/flame ionization detection (FID). The detection limit is 50 ng/L and the average recovery is approximately 82% (Ghittori et al. 1993). Benzene in urine has also been determined using headspace analysis with capillary GC/photoionization detection (PID). The detection limit is 40 ng/L (Kok and Ong 1994). 

Another type of detector that is used relatively often for gas chromatography is called the ion trap detector. In some cases, this detector is called a mass selec-... 

The mass spectrometer serves for the exact determination of the masses of atoms and molecules as well as for the registration of the mass spectra from particle mixtures to mass and relative proportion. The first ion trap detector was developed in 1919 by F.W. Aston. 

It is obvious from the working principle of the ion trap detector that this is equally a universal detector as is the thermal conductivity detector. The analysis of the mixtures of compounds with this type of detector is possible not only by retention time of the compound in the column, but also by the composition of the ions of this compound. Usually, libraries of the compounds for the ion trap detector are much more extensive than the libraries for the thermal conductivity detector. However, the more extensive possibilities for knowing which compound exited the column makes this detector an excellent detector for the specialist, but introduces many difficulties for beginners. 

Analysis of the samplers was by TD/GC. The bulk of samplers were analysed on a system composed of a Perkin-Elmer ATD50 and an 8310 GC fitted with an FID. Fifty duplicate samplers were analysed using a second TD/GC system (Perkin-Elmer ATD400/ 8700 GC) incorporating a Finnigan ion trap detector (ITD). All tubes were desorbed at 250°C for 10 min under a flow of helium with an outlet split of 30 1. The two GCs were equipped with the same column (SGE, BPIO, 25m) and used the same temperature programme (40°C for 1 min, 2°C/min up to 75°C then S C/min up to 220°C). 

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