Fast chromatography devices

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]. 

The level of purity as well as the required amount of compound is generally imposed by the targeted biological evaluation. The crude cleavage product, however, often does not meet the purity requirement. To allow quick parallel purification and structural assessment an increasing amount of apparatus, softwares and techniques are required in laboratories. The most efficient is probably fast LC/MS and its multicolumn evolution that enables purification of hundreds of compounds a day. Similarly, parallel chromatography devices and TLC spotting apparatus can be found on the market. ... 

The special instrumentation required for ultra-fast chromatography comprises a dedicated ultra-fast column module (UFM), see Figure 2.129, or low-thermal-mass device (LTM), comprising a specially assembled fused silica column for... 

Another example of on-line monitoring of enzyme activities was given by Kunnecke et al. [88], when a FIA-system was used for the determination of enzyme activities during protein purification by fast protein liquid chromatography (FPLC). Photometric assays for four different oxidases were established in a FIA-system extending the linear range by the so-called zone sampling method. The FIA-device was coupled to the FPLC unit behind a... 

Ertl H., Breit U., Kaltschmidt H., and Oberpriller H., Determination of the HMX and RDX content in synthesized energetic material by HPLC, FT-MIR, and FT-NIR spectroscopies. New separation device that allows fast gas chromatography of large samples, SPIE Proc., 2276, 58-68, 1994. 

The initial PIA purification method was developed by Mack et al. (3). These authors used a different, two-step chromatography protocol involving size-exclusion and ion exchange chromatography on Sephadex G-200, Q-Sepharose, and S-Sepharose. A similar purification method has been described recently to isolate a PIA-related polysaccharide polymer in E. coli (7). Briefly, E. coli cells were incubated in 50 raM Tris-HCL buffer (pH 8.0), 100 mg lysozyme, and 0.1 M EDTA at room temperature for 2 h. Phenol/chloroform extraction steps were performed to separate protein and debris contamination from the polysaccharide. Samples were concentrated by ultrafiltration devices (10,000 MW cut off) and fractionated on a fast protein liquid chromatography (FPLC) system with a Sephacryl S-2000 column (equilibration and elution buffer 0.1 MPBS, pH 7.4). 

Cryogenic traps are convenient accumulation and injection devices for fast gas chromatography and interfaces for coupled-column gas chromatography, where a heartcut sample is collected and focused from the first column, and reinjected into the second column. The main requirement for a cryogenic trap used in these applications is efficient accumulation over time with rapid injection of the collected analytes as a narrow pulse in both time and space. Commercially available systems using a capacitance discharge for heating provide injection bandwidths of 5-20 ms. 

Due to the very fast ion-exchange equilibrium, such an analysis can be performed either in batch ot even in flow injection mode [147, 182, 183], as in the example reported in Fig. 7.10. This property allows the application of ZMEs in the frame of detectors for ion chromatography. In this case, the renewal of the electrode that includes more or less high quantities of the analyte may consist of a step in which a short stream of the pristine electroactive species is made flow on the electrode surface to restore the initial capacity of the zeolite. The chromatographic carrier reaching the detection zone either contains a size-excluded cation, as happens in Fig. 7.10, or consists of pure water, as in the case of ion chromatography with a suppression device [156, 183]. 

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