Chromatography equipment

In industry and academia the need often arises to isolate portions of a polymer sample, whether it be to separate low molecular weight material from a sample or to actually fractionate the polymer across its molecular weight distribution. If gram quantities of isolated polymer are needed, true preparative chromatography equipment and techniques are usually necessary. 

The method of choice for the determination of a- and P-endosulfan in blood, urine, liver, kidney, brain, and adipose tissue is gas chromatography equipped with an electron capture detector (GC/ECD) (Coutselinis et al. 1976 Demeter and Heyndrickx 1979 Demeter et al. 1977 Le Bel and Williams 1986). This is because GC/ECD is relatively inexpensive, simple to operate, and offers a high sensitivity for halogens (Griffith and Blanke 1974). After fractionation of adipose tissue extracts using gel permeation chromatography, detection limits of low-ppb (1.2 ng/g) were achieved for endosulfan and other chlorinated pesticides using GC/ECD (Le Bel and Williams 1986). 

This paper concerns the main properties of water soluble pectins in sol and gel states. First of all, the methods of purification and characterization are discussed. The method of steric exclusion chromatography equipped with different detectors is demonstrated as the most useful to determine the macromolecular characteristics of these polymers the role of aggregation is pointed out. 

The best way then to characterize the pectins is the steric exclusion chromatography equipped with a multidetection and particularly a light scattering detector [13]. 

At the moment, one recommends to determine the molecular characteristics of pectins using SEC chromatography equipped with a differential refractometer, a multiangle laser light scattering detector and a viscometer as previously described [25]. This technique needs no calibration with the usual molecular weight standards such dextrans and pullulans... 

There are many other suppliers of gas chromatography equipment, some of which are discussed further in Table 1.7. 

There are numerous suppliers of gas chromatography equipment, a selection of which are given below... 

HPLC instrument equipped with a UV-vis detector column chromatography equipment. 

LaCourse W. 2000. Column liquid chromatography equipment and instrumentation. Anal Chem 72 37R-51R. 

It is seen that the 1 micron column can provided an efficiency of over two hundred thousand plates whereas the column 100 micron in radius can provide an efficiency of over two billion theoretical plates (assuming an inlet pressure of 1000 p.s.i). It will be seen later, however, that the practical limitations of present day chromatography equipment render the realization of even a modest performance from LC capillary columns extremely difficult. 

Figure 3. Chromatogram of organo-thiophosphates using Tracor 550 gas chromatography equipped with flame photomeric detector specific for phosphorous (A)...

D. Parroitt, Performance verification testing of high performance liquid chromatography equipment, LC-GC, 12(2), 135, 1994. 

The catalytic test of isohexane cracking was carried out by a pulse method. Nitrogen, purified by flowing through MS 13X trap at dry-ice temperature, was used as a carrier gas (20 ml min 1). The catalyst (typically 40 mg) was placed in a quartz tube and pretreated in flowing nitrogen at 873 K. A pulse of isohexane (0.1 pi) was injected into a flow of carrier gas, and the reaction products were analyzed with an on-line gas chromatography equipped with FID. 

High-performance liquid chromatograph (HPLC e.g., Waters Chromatography) equipped with column heater, solvent pump, UV detector (set at 210 nm), integrator, autosampler, and (for manual injection) a 10-pl sample loop 15 x 0.46-cm YMC-ODS-AQ analytical column (AQ12S031546WT, Waters Chromatography)... 

H.M. McNair and C.D. Chandler, High-pressure liquid chromatography equipment. 

Due to the limited time available for NMR data acquisition and the additionally reduced stability under flowing conditions, the on-flow mode is limited to the acquisition of ID spectra of the major peaks from a chromatographic separation. Minor compounds are normally not accessible. As no interruption or control of the chromatographic stage is necessary, the experiments can be carried out with standard chromatography equipment without the necessity of special equipment or software. The whole chromatogram is covered by the NMR spectra and all NMR-active compounds are detected. 

A number of analytical techniques have been used for measuring aluminum concentrations in environmental samples. These include GFAAS, FAAS, NAA, ICP-AES, ICP-MS, spectrophotometry using absorbance and fluorescence detection, phosphorimetry, chromatography and gas chromatography equipped with an electron capture detector (GC/ECD) (Andersen 1987, 1988 Benson et al. 1990 ... 

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