Instrumentation

The essential elements of instrumentation were developed by the early 1960s, but the advent of the

Table 3 Chromatographic properties of commercially available columns

(m)

Phase ratioa

(mm)

(column)

N/length

Classical

2

2.16

10% (w/w)

12

0.55

3640

1820

Packed

2

2.16

5% (w/w)

26

0.50

4000

2000

WCOT''

30

0.10

0.10

249

0.06

480 000

16 000

30

0.10

0.25

99

0.08

368 550

12 285

30

0.25

0.25

249

0.16

192 000

6400

30

0.32

0.32

249

0.20

150 000

5000

30

0.32

0.50

159

0.23

131 330

4380

30

0.32

1.00

79

0.29

102 080

3400

30

0.32

5.00

15

0.44

68 970

2300

30

0.53

1.00

132

0.43

70 420

2340

30

0.53

5.00

26

0.68

43 940

1470

aPhase ratio = volume of gas phase/volume of liquid phase in the column (columns with a low phase ratio are more retentive). ''Selecting a WCOT column: narrow-bore thin-film columns are used for high speed gas chromatography; columns with 0.25 and 0.32 mm internal diameters are used for general high performance applications; wide-bore columns with thicker films are used as replacements for packed columns; thin-film columns are employed for the separation of compounds of low volatility; and thick-film columns are used for separating volatile compounds and to obtain maximum sample loadability.

aPhase ratio = volume of gas phase/volume of liquid phase in the column (columns with a low phase ratio are more retentive). ''Selecting a WCOT column: narrow-bore thin-film columns are used for high speed gas chromatography; columns with 0.25 and 0.32 mm internal diameters are used for general high performance applications; wide-bore columns with thicker films are used as replacements for packed columns; thin-film columns are employed for the separation of compounds of low volatility; and thick-film columns are used for separating volatile compounds and to obtain maximum sample loadability.

microprocessor has effected a radical change in design and use. Most gas chromatographs now have self-diagnostic software so that faults may be revealed and located. There has also been a revolution in the handling of the data produced (see below).

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

Get My Free Ebook


Post a comment