Fast GC-MS

The full-scan mode is needed to achieve completely the full potential of fast GC/MS. Software programs, such as the automated mass deconvolution and identification system (AMDIS), have been developed to utilize the orthogonal nature of GC and MS separations to provide automatically chromatographic peaks with background-subtracted mass spectra despite an incomplete separation of a complex mixture. Such programs in combination with fast MS data acquisition rates have led to very fast GC/MS analyses. 

There are at least three approaches to fast GC/MS (1) use of microbore columns with time-of-flight mass spectrometry (TOFMS) (2) use of low-pressure (LP)-GC/MS to aid separations at increased flow rate " and (3) use of supersonic molecular beam mass spectrometry (SMBMS) (also known as supersonic GC/MS), which can accept increased flow rates and short analytical columns."... 

The use of stable, narrow-bore columns and fast oven temperature programmes result in analysis times of 5-15min, while maintaining the final resolution obtained with conventional GC approaches. Fast GC-MS (5-200 s) requires the matching of several technologies ... 

As to the optimum column diameter for fast GC-MS, convincing evidence [238] shows that ... 

An alternative fast GC-MS mode, low-pressure GC-MS, is based on the high optimal velocity for the carrier gas obtained when a separation is performed under reduced pressure. The pressure required for LPGC-MS is 120 kPa, generating a flow of ImLHemin. The main advantages of low-pressure GC-MS are shown in Table 7.29. 

On-line SFE-GC-MS was used for the analysis of organic extractables from human hair [312]. Van Lieshout et al. [313] described GC-MS analysis of an SFE extract of an (ABS) impact-modified PC/PBT blend identifying Ionol CP, Dressinate, cyclic PBT trimer, Irganox 1076 and Irganox PS 800. TD-GC-MS was used in the development of flame retardants, and for the analysis of fire debris [314]. The application of laser desorption fast GC-MS analysis was employed in the analysis of DOP on a stainless-steel surface [221]. 

The use of GC-MS in polymer/additive analysis is now well established. Various GC-based polymer/additive protocols have been developed, embracing HTGC-MS, GC-HRMS and fast GC-MS with a wide variety of front-end devices (SHS, DHS, TD, DSI, LD, Py, SPE, SPME, PTV, etc.). Ionisation modes employed are mainly El, Cl (for gases) and ICPI (for liquid and solid samples). Useful instrumental developments are noticed for TD-GC-MS. GC-SMB-MS is a fast analytical tool as opposed to fast chromatography only [104]. GC-ToFMS is now about to take off. GC-REMPI-MS represents a 3D analytical technique based on compound-selective parameters of retention time, resonance ionisation wavelength and molecular mass [105]. 

Leaf samples of various Erythroxylum species have been investigated for their cocaine content by a fast GC-MS method [29]. Amongst the 51 analyzed species, 28 had not been examined previously and cocaine was detected in 23 wild species. Cocaine content was less than 0.001 % for all wild species, except for Erythroxylum laetevirens in which a 10-fold higher concentration was determined. The qualitative... 

Mondello, L G. Zappia, G. Errante, P. Dugo, and G. Dugo. 2000. Fast-GC and Fast-GC/MS for the analysis of natural complex matrices. LC-GCEur., 13 495-502. 

Another work, from Mondello et al. [26], determined the PASs using fast GC-MS, by employing shorter and narrower columns besides high-speed MS detector. The MS operated in FS mode, and quantification was performed in EIC mode. The main novelty of the work basically consisted in a very short run time (less than 5 min). However, the same above-mentioned problems regarding coelutions are expected to occur. 

Strano-Rossi S, Bermejo AM, de la Torre X, Botre F (2011) Fast GC-MS method for the simultaneous screening of THC-COOH, cocaine, opiates and analogues including buprenorphine and fentanyl, and their metabolites in mine. Anal Bioanal Chem 399 1623-1630... 

The analytical needs of the petroleum industry continue to drive the ever-increasing selectivity and sensitivity of GG-MS instrumentation and provide analysts in other industries with new analytical techniques that they may apply as their samples become more complex. New innovations in GC-MS to gain ever greater speed and resolution in GG and MS, such as fast GC-MS, GC-GC-MS, and GC-TOF-MS, will open new avenues of analysis and problem solving for tomorrow s upstream and downstream analysts. 

Solid-phase microextraction (SPME) is becoming a modern alternative to SPE and LEE. Solid-phase microextraction is a solvent-free and concentrating extraction technique especially for rather volatile analytes. It is based on the adsorption of the analyte on a stationary phase coating a fine rod of fused silica. The analytes can be desorbed directly into the GC injector. Fast GC-MS procedures for screening, e.g., for barbiturates [31] or amphetamines [32], have been published. 

Figure 4.114 Fast GC-MS analysis of a sewage sludge sample with the extracted mass chromatograms of tri-(m/z 256), tetra-(m/z 293), penta-(m/z 326) and deca-chlorbiphenyl (m/z 498, ISTD).

---