SU1249450A1 - Thermal electron detector for gas chromatography - Google Patents

Description

 112

The invention relates to analytical chemistry, primarily to the design of a thermionic detector for gas chromatography, and is intended for the analysis of phosphorus, nitrogen, and chlorine-containing organic compounds, in particular pesticides.

The purpose of the invention is to increase the threshold sensitivity and stability.

Figure 1 shows the scheme of the detector in figure 2 - burner thermionic detector.

The detector consists of a housing 1, a nozzle of a hydrogen burner 2, a tablet 3 of alkali metal salt and an inert filler, a collector 4 and an annular potential 5 electrode and spring 6. In the lower part of the detector housing 1 are channels for supplying gases: air 7, hydrogen 8 and carrier gas 9. The detector also contains insulators 10–12.

 The thermionic detector works in a barely blowing way.

A mixture of the analyzed compounds with a carrier gas exiting the chromatographic column is fed through channel 9 to the nozzle of the burner 2 and burned in a flame of hydrogen. The required initial background current of the detector (8 x X 10 A) at a fixed hydrogen flow rate is set manually by re-t

5P2

1 by clearing the position of the tablet 3 salt relative to the upper cut of the burner nozzle 2. When organometallic compounds get into the flame of hydrogen, the concentration of charge carriers increases, which in turn causes a signal to appear.

Tests of the proposed detector show that the lower limit of detection of phosphorus-containing compounds is cHi-1.5 times, and for nitrogen-containing compounds, 2 times compared with the known device. This increases the stability of the thermionic detector by eliminating the effect of reducing the salt vapor concentration.

The table shows the results of determining the threshold sensitivity to some electroorganic compounds, obtained using the proposed thermionic detector.

Compound Threshold of scent, g / s

1-10

-1/1

3.6-10

2-10

-) 2

Editor A.Shishkin

FIG. 2

Compiled by V.Ponomarev Tehred M.Hodanich

Corre Poppy

4230/46 Circulation 778

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

Proofreader A.Obruchar Subscription

Claims (1)

THERMOION DETECTOR FOR GAS CHROMATOGRAPHY, containing a housing, a nozzle of a hydrogen burner, a tablet of an alkali metal salt and inert for supplying the analyzed gas, hydrogen and air, characterized in that, in order to increase the threshold sensitivity and stability of operation, the ring potential electrode is mounted on a hydrogen burner below the level of its nozzle and is in contact with the tablet, installed with the ability to move along the height of the detector, under which there is a spring, which compresses the tablet to the ring potential cial electrode.