Full scan analysis

In a subsequent development, a novel, real-time peak detection algorithm known as intelligent automated LC/MS/MS (INTAMS) was developed for the analysis of samples generated by in vitro systems.27 INTAMS also requires two separate chromatographic runs for each sample. It allows the user to detect the two most abundant ions of all components and also any predetermined metabolite precursor ions. In the second chromatographic run, INTAMS conducts automatic product ion scanning of molecular ions of metabolites detected in the first full scan analysis. 

High sensitivity full scan analysis of D3-11 NOR-9-carboxyl 7-9 tetrahydrocannabinol by the ion-trap detector. Finnigan MAT Application Data Sheet PADS 14. 

Both of the above examples illustrate that the sensitivity of the MDF method, in general, is comparable to PIS analysis and better than NLS methods (Figs 6.9 and 6.10). The sensitivity of the MDF method is attributed at least in part to the full-scan capability of high-resolution mass spectrometers such as the Q-TOF and LTQ-FTICR, which could be several times more sensitive than full-scan analysis by a triple-quadrupole mass spectrometer (Kostiainen et al., 2003). 

In conclusion, the sensitivity and specificity for screening for oxidative metabolites by the three LC-MS methods are variable, compound-dependent, and complementary to each other. The MDF method requires a simple, generic full-scan analysis using a mass spectrometer equipped with high-resolution capability, and the accurate mass information obtained can provide empirical formula information for metabolites and their fragments. Since MDF employs a different detection... 

Selection of ions for selected-ion monitoring or full-scan analysis... 

Screening B. 5 ml narcotic analgesics and S-block-ers excreted free and/or conjugated - basic hydrolysis - liquid-liquid extraction, concentration -trimethylsilyl (TMS) derivatization - GC-MS full scan analysis ... 

Screening F. 1 ml corticosteroids free and conjugated - extraction - LC-MS SIM and full scan analysis. 

Two general modes of data acquisition are available in MS full-scan acquisition and selective ion monitoring (SIM). In full-scan analysis, a continuous series of mass spectra is acquired during the chromatographic run. For high-efficiency open capillary GC columns, sufficiently fast scanning is required in order to acquire a sufficient number of data points (typically 10 to 20) to adequately describe the chromatographic peak profile. However, in routine quantitative analysis of a limited number of components, better results in terms of lower detection limits are achieved by the use of SIM, in which the intensity of a (number of) ion(s) is monitored. The choice between full-scan and SIM acquisition in a particular application depends on the required detection limit and information content. 

Full scan analysis of an average substance concentration to determine the selective ions (SIM masses, two to three ions/component) chose more potential SIM ions as finally required as special matrix conditions are to be taken into account. Chose SIM masses with highest S/N ratio. Determination of the retention times of the individual components. Establishment of the data acquisition interval (time window) for the individual SIM descriptors, or use the retention timed SIM technique with a symmetrical acquisition window centered to the compound retention time. Test analysis of a low standard (or better, a matrix spike) for optimization (SIM masses, separation conditions). 

Fast full scan analysis with deconvolution... 

Full-scan and selected ion monitoring (SIM) represent at least 95% of the MS analysis performed today. Full-scan analysis has always offered three benefits (1) selectivity based on m/z detection, (2) universal detection across a wide operating range and (3) library searches (spectral comparison) for confirmation of identity. Since the source of the data for SIM is the same as for full scan, SIM offers no solutions to interference problems. The primary advantage of SIM has always been its improved signal-to-noise ratio (S/N) versus full scan and its interpretation simplicity (ion ratios). 

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