Finnigan 3300 chemical ionization

Figure 6 presents the average values with standard error obtained for A9-THC, 11-0H-A9-THC and cannabinol from plasma of male volunteers receiving A9-THC by intravenous infusion. The measurements covered a 24 hour period. A9-THC values obtained with the LKB-9000 El source were in close agreement with the data obtained on the Finnigan 3300 chemical ionization (Cl) source. 

The Finnigan chemical ionization source was modified by the addition of two cartridge heaters. Eluate entered the source through a heated 1/2" probe and excess solvent was removed by a mechanical vacuum pump connected directly opposite the eluate entrance. The interface consisted of 1 meter deactivated silica capillary tubing (ID, 60 OD, 0.008"), led from the outlet of microbore column and threaded through the probe. The probe design has been previously described (26). For all analyses, the probe was operated at 240 C and the source at 250 C. The analyzer pressure was 10 b torr. 

The standard MAT 90 ion source is used for optimized FD/FI mode by means of the newly designed FD/FI probe. Conversion from electron impact (El), chemical ionization (Cl) or fast ion bombardment (FAB) to FD/FI operation does not require the exchange of the ion source. The FD/FI probe accommodates both the field emitter and the extraction electrodes, mounted at the probe tip. Both are introduced as a unit into the ion source through the ionization volume exchange lock without breaking vacuum. The fast and simple changeover illustrates the versatility of the Finnigan MAT 90 with no compromise on the performance. 

Syka, J.E.P. Positive ion chemical ionization with an ion trap mass spectrometer. Finnigan MAT IDT 19. 

Eichelberger, J.W. and Slivon, L.E. Existence of self chemical ionization in the ion-trap detector. Finnigan MAT IDT 48. 

HPLC - Beckman 125 binary gradient pumps, 168 diode-array detector, 507 autosampler MS - Ion-trap mass spectrometer Finnigan LCQ equipped by APCI (atmospheric pressure chemical ionization), data analyzed in negative mode, spectra confirming found compounds were obtained from tandem mass spectromectry (MS/MS). 

The electron impact (Figure 9) and chemical ionization (figures 10 and 11) spectra of benzoic acid were obtained using a Finnigan Mat 8200 mass spectrometer. Methane and isobutane were used as the reactants for the Cl methods. The studies were performed at 220°C(EI) and 130-140°C (Cl), 0.05 mA, and 70 eV. The assignment of the main fragments is presented in Table 6. 

A Finnigan MAT TSQ mass spectrometer was used to record the mass spectra of brinzolamide. The conditions were 0.3 mA current, 1100-volt acceleration voltage and 10 preamp sensitivity. The ionization voltage was 70 eV for El (electron impact) ionization mode. For Cl (chemical ionization) mode, a positive ionization voltage of 100 eV and a pressure of 0.3 torr of methane were used. The El and Cl spectra are shown in Figures 12 and 13, respectively. Peak assignments for the El and Cl spectra are listed in Table 6. Both the Cl and El spectra have an MH peak at m/z = 384. 

The chemical ionization mass spectrum of cimetidine and the major fragmentation ions are presented in Figure 8 and Table 4. The spectrum was obtained using a Finnigan lYbdel 3200 quadrupole mass spectrometer fitted with a chemical ionization source. The sample, applied to the probe from an acetone solution, was introduced via the direct inlet system. Methane was used as the reactant gas. 

The electron impact (El) mass spectrum at 70 eV recorded on Varian Mat 311 mass spectrometer and the methane derived chemical ionization (Cl) mass spectrum obtained with Finnigan 4000 mass spectrometer are shown in Figures 1 and 2 respectively. The (El) spectrum Fig. 

Gas-Chromatography Mass Spectral (GC-MS) Analyses. Several different studies were carried out. The main study was done using a Finnigan MAT 4500 series quadrupole mass spectrometer and a 60 m X 0.32 mm l.d. DB-1 bonded fused silica capillary GLC column. The column was programmed from 25-250°C at 4° per minute with an inlet pressure of 14 psi. Chemical ionization (Cl) mass spectra on some of the components were also obtained using a VG Micromass 70/70 mass spectrometer with Isobutane as the reactant gas. 

Mass spectra were obtained with the following conditions ES (Electrospray) on anLCTOF MICROIVIASS El (Electronic Impact) and D/CI (Desorption/Chemical Ionization ammonia) on a SSQ7000 FINNIGAN LSIMS (Liquid Secondary Ion Mass Spectrometry) with a SCIEX PERKIN ELMER (Cs 35 KeV 3-nitrobenzyl alcohol matrix). 

Gas chromatographic/mass spectrometry (GC/MS) results were obtained at the Ohio State University Chemical Instrumentation Center using a Finnigan 4021 GC/MS instrument. Both electron impact and chemical ionization were performed on samples following separation of compounds by a gas chromatograph equipped with capillary columns containing 3% 0V-17 or 5% carbowax 20M. 

Thernospray HPLC/MS. Urine extracts were analyzed by thermospray/HPLC/MS to Identify the metabolites present. A Finnigan 4500 series mass spectrometer Interfaced with a Vestec Thermospray unit was used to perform the analysis. The aerosol thermocouple of the Interface was replaced with a repeller which was connected to an external power supply. The samples were analyzed under thermospray/fllament chemical Ionization with pulsed +/- Ion detection. A mobile phase consisting of acetonitrlle/0.1 M ammonium acetate with a linear gradient of 9X to 65% over 30 minutes was used In the anlaysls. 

The chemical ionization spectrum, shown In Figure 11, was obtained on Finnigan 4000 mass spectrometer using methane gas as a reagent with Ion electron energy of 100 eV, Ion source pressure of 0.3 Torr, Ion source temperature of 150 C and emission current of 300 pA. The spectrum Is dominated by a quasimolecular Ion (H + 1). Two peaks appearing at m/e 353 and m/e 365 are attributable to the transfer of carbocatlons from the carrier gas. The mass spectra assignment of the... 

Detector MS, Finnigan MAT TSQ-7000 quadrupole, atmospheric pressure chemical ionization, m/z 190, corona voltage 1.8 kV, corona current 5.0 gA, capillary temperature 220°, electron multiplier 1400 V, vaporizer temperature 400°... 

GC-MS Analysis of Fragrances Using Chemical Ionization on the Ion Trap Detector An Easy-to-Use Method for Molecular Weight Information and Low Level Detection, Finnigan MAT Application Report No. 220. 

With the introduction of the reproducible chemical ionization into ion trap mass spectrometers, the first commercial Cl library with over 300 pesticides was produced by Finnigan Corp. in 1992. The introduction of substructure libraries (MS/MS product ion spectra) and accurate mass spectra libraries is currently ongoing (NIST). The commercially available libraries are divided into general extensive collections and special task-related collections with a narrow range of applications. 

Pulsed positive ion negative ion chemical ionization, the alternating data acquisition of positive and negative ions formed during chemical ionization, patented by former Finnigan Corp., San Jose, CA, USA. 

Hunt, D.F. (1976), Selective reagents for chemical ionization mass spectrometry. Finnigan Spectra, 6,1. 

The second problem is that ion-ion or ion-neutral reactions can occur. Reactions (e.g., proton transfer) result in high abundance of protonated molecular ions in the mass spectrum. Thus QIT can be disadvantageous for determining chemical composition in manual spectral interpretation, because the presence of the (M + l)" ion tends to confuse the interpretation. Library spectral matching, however, is not affected if the spectral matching algorithm reflects the unique features of the QIT spectrum. An external ionization source with ion injection into the QIT is an alternative solution, because only ions are present in the trap (i.e., neutral analyte molecules that could participate in ion-molecule reactions are not present). The Thermo Finnigan PolarisQ GC/MS is an example of such an instrument. 

Figure 6.2 Positive-ion electrospray ionization tandem mass spectra of choline lyso-glycerophospholipid regioisomers. Positive-ion ESI tandem MS analyses of sodiated 1-hexadecanoy 1-2-hydroxy-in-glycero-3-phosphocholine (a) and sodiated l-hydroxy-2-hexadecanoyl-in-glycero-3-phosphocholine (b) was performed on a TSQ mass spectrometer (Finnigan TSQ MAT 700). Colhsion activation was carried out with collision energy of 20 eV and gas pressure of 1 mTorr. The asterisks indicate the product ions at tn/z 335 in (a) and m/z 415 in (b) present in very low abundance. Han and Gross [22], Reproduced with permission of the American Chemical Society.

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