Product ion filter

Ruan, Q., Peterman, S., Szewc, M. A., Ma, L., Cui, D., Humphreys, W. G., and Zhu, M. (2006). Metabolite detection and characterization by high-resolution orbitrap mass spectrometry Application of mass defect and product ion filtering techniques. In Proceedings of the 54th ASMS Conference on Mass Spectrometry and Allied Topics, Seattle, WA. 

FIGURE 15.5 Work flow of metabolic soft spot determination using EMS-EPI or MIM-EPI EIC, extracted ion chromatography PIF, product ion filter NLF, neutral loss filter. 

Product ion filter (PIF) and neutral loss filter (NLF) [174,175] Predicted fragmentation Sensitive detection of unexpected metabolites Not suited for metabolites that do not generate significant predictable fragmentation... 

In the analyses, isotope-dependent MS/MS acquisition methods with or without polarity switching are employed to record MS/MS spectra of analytes that display isotope patterns similar to those predefined. Then, NL filtering of 129 and 307 Da in the positive ion mode, or product ion filtering of m/z 272 in the negative ion mode, are carried out to identify GSH adducts [161,162],... 

ToFs can also be used in combination with other mass analysers. Both hybrid sector and quadrupole systems are available. oaToF-MS has been interfaced to a quadrupole mass filter and hexapole gas collision cell, such as to allow recording of mass spectra and product ion spectra with good mass resolution (ca. 10000), high sensitivity, high mass range (ca. 10 000 Da) and high mass accuracy (<5ppm) [177,178]. QqToFMS may be fitted with API sources with flow-rates from nL... 

Polymerizations were carried out in a jacketed, 1-gal, stirred, pressure tank reactor. Typical reactions were run by adding water, alcohol, or chain transfer agent, phosphate buffer, and persulfate to the reactor. The reactor was pressurized with CTFE monomer. Sulfite solution was fed at a rate to maintain reaction. Copper and iron ions were used at times as catalysts by adding cupric sulfate or ferrous sulfate.3 The product was filtered, washed with 90 10 water methanol followed with deionized water. The product was dried at 110°C. 

Fig. 11.16. Representation of three tandem mass spectrometry (MS/MS) scan modes illustrated for a triple quadrupole instrument configuration. The top panel shows the attributes of the popular and prevalent product ion CID experiment. The first mass filter is held at a constant m/z value transmitting only ions of a single mlz value into the collision region. Conversion of a portion of translational energy into internal energy in the collision event results in excitation of the mass-selected ions, followed by unimolecular dissociation. The spectrum of product ions is recorded by scanning the second mass filter (commonly referred to as Q3 ). The center panel illustrates the precursor ion CID experiment. Ions of all mlz values are transmitted sequentially into the collision region as the first analyzer (Ql) is scanned. Only dissociation processes that generate product ions of a specific mlz ratio are transmitted by Q3 to the detector. The lower panel shows the constant neutral loss CID experiment. Both mass analyzers are scanned simultaneously, at the same rate, and at a constant mlz offset. The mlz offset is selected on the basis of known neutral elimination products (e.g., H20, NH3, CH3COOH, etc.) that may be particularly diagnostic of one or more compound classes that may be present in a sample mixture. The utility of the two compound class-specific scans (precursor ion and neutral loss) is illustrated in Fig. 11.17.

The formation of the azo compound takes place slowly on the addition of the dimethylaniline, but the speed of the reaction is greatly increased when the hydrogen ion concentration is lowered by the addition of the sodium acetate. It is nevertheless necessary to allow the reaction mixture to stand a long time if the product be filtered off after only twenty-four hours, a further quantity of dye will separate from the filtrate on standing. The hydrochloride of methyl red is only sparingly soluble in cold water, and is apt to separate in blue needles if the acidity is not sufficiently reduced. 

The initial halogenated polymeric materials were obtained from the polyvinyl chloride-polyvinylidene chloride, PVC-PVDC (Rovil fiber) and chlorinated polyvinyl chloride, PVC. Dehydrochlorination was performed in the presence of a base solution in a polar organic solvent (dimethylsulfoxide, acetone or tetrahydro-furane). The products were filtered and extracted with water in a Soxhlet apparatus until all chloride ions were removed. Thermal treatment was performed in a tubular furnace in CO flow at 10 cm min". ... 

Figure 24-22 Selected reaction monitoring in gas chromatography-mass spectrometry, (a) Reconstructed total ion chromatogram of extract from orange peel with electron ionization, (b) Selected reaction monitoring with the precursor ion m/z 293 selected by mass filter Q1 in Figure 22-21 and product ion m/z 264 selected by mass filter Q3. The chromatogram is a graph of intensity at m/z 264 from Q3 versus time. [Courtesy Thermo Ftnnlgan GC ana GC/MS Division, San Jose. CA.J...

Figure 8 Dissociation of (a) glow discharge generated copper dimer ions using a filtered noise field results in (b) bare copper product ions.

Fig. 3. Schematic diagram of the Selected-Ion Flow Tube (SIFT) tandem mass spectrometer. Ions from the ion source are selected with a quadrupole mass filter before injection into the flow tube. A second quadrupole mass filter is used downstream to separate reactant and product ions in the sampled reaction mixture. The He pressure in the flow tube is ca. 0.4 Torr...

---