Quadrupole mass filters provide a robust means of sorting ions in a mass spectrometry experiment. When these mass analysers are incorporated in a triple quadrupole (QQQ) setup, which consists of three quadrupole mass filters in series, various specialised forms of quantitative and qualitative mass spectrometry can be conducted.
This is achieved via the use of the first and third quadrupoles (Q1 and Q3, respectively) as mass filters, whilst the second quadrupole (Q2) is utilised as a collision cell in which precursor ions undergo collision-induced dissociation to produce fragment ions.
The ABI 4000 QTrap is a hybrid QQQ/linear ion trap mass spectrometer, to which both 1D and 2D nano liquid chromatography (LC) separations can be interfaced. This instrument allows the array of scan types available in a QQQ setup to be exploited, with increased functionality obtained via linear ion trap mass analysis.
The system is particularly well suited to highly sensitive, targeted quantitative analyses of, for example, metabolites and complex peptide mixtures in multiple reaction monitoring (MRM) experiments. Other scan types include precursor ion scans and constant neutral loss scans, which provide highly specific means of monitoring given classes of analytes, for example classes of post-translational modifications.
Illustrative publications (with DOI Links) involving the AB SCIEX 4000 QTrap at BMSF:
- Wasinger VC; Curnoe D; Bustamante S; Mendoza R; Shoocongdej R; Adler L; Baker A; Chintakanon K; Boel C; Tacon PSC, 2019, 'Analysis of the Preserved Amino Acid Bias in Peptide Profiles of Iron Age Teeth from a Tropical Environment Enable Sexing of Individuals Using Amelogenin MRM', Proteomics, vol. 19, pp. e1800341, http://dx.doi.org/10.1002/pmic.201800341