FID 氢火焰检测器
简单介绍
氢火焰检测器的原理 1)当含有机物 CnHm的载气由喷嘴喷出进入火焰时,在C层发生裂解反应产生自由基 :CnHm ──→ · CH(2)产生的自由基在D层火焰中与外面扩散进来的激发态原子氧或分子氧发生如下反应: · CH + O ──→CHO+ + e
FID 氢火焰检测器的详细介绍
The principle of hydrogen flame detector
1) When the carrier gas co ntaining organic CnHm emitted from the nozzle into the flame, in the C layer cracking reaction occurs free radicals:
CnHm ─? · CH
(2) generated in the D-layer flame with the outside diffusion of the excited state of the atomic oxygen or molecular oxygen reaction occurs as follows:
· CH + O - → CHO + + e
(3) the generation of positive ions CHO + and a large number of water molecules in the flame collision and molecular ion reaction:
CHO + + H2O - → H3O + + CO
(4) chemical io nization of the positive ions and electrons in the application of a co nstant DC electric field, respectively, under the action of bipolar orientation to produce micro-current (a bout10-6 ~ 10-14A);
(5) in a certain range, the size of micro-current into the ion chamber is proportio nal to the measured compo nent quality, so the hydrogen flame detector is the quality of the detector.
(6) The io nization efficiency of the compo nent in the hydrogen flame is very low, anda boutone half of a million carbon atoms are ionized.
(7) the ion current signal output to the recorder, the peak area and compo nent mass is proportio nal to the chromatographic outflow curve
Hydrogen flame detector structure
(1) between the emitter and collector to add a certain DC voltage (100-300V) co nstitutes an external electric field.
(2) hydrogen flame detector need to use three kinds of gas:
N2: carrier gas carrying sample components;
H2: for the gas;
Air: combustion gas.
Use the need to adjust the ratio between the three, the detector sensitivity to achieve the best.
氢火焰检测器氢火焰检测器 详细信息:
氢焰检测器的原理
1)当含有机物 CnHm的载气由喷嘴喷出进入火焰时,在C层发生裂解反应产生自由基 :
CnHm ──→ · CH
(2)产生的自由基在D层火焰中与外面扩散进来的激发态原子氧或分子氧发生如下反应:
· CH + O ──→CHO+ + e
(3)生成的正离子CHO+ 与火焰中大量水分子碰撞而发生分子离子反应:
CHO+ + H2O ──→H3O+ + CO
(4)化学电离产生的正离子和电子在外加恒定直流电场的作用下分别向两定向运动而产生微电流(约10-6~10-14A);
(5) 在一定范围内,微电流的大小与进入离子室的被测组分质量成正比,所以氢焰检测器是质量型检测器。
(6) 组分在氢焰中的电离效率很低,大约五十万分之一的碳原子被电离。
(7)离子电流信号输出到记录仪,得到峰面积与组分质量成正比的色谱流出曲线
氢焰检测器的结构
(1) 在发射和收集之间加有一定的直流电压(100—300V)构成一个外加电场。
(2) 氢焰检测器需要用到三种气体:
N2 :载气携带试样组分;
H2 :为燃气;
空气:助燃气。
使用时需要调整三者的比例关系,检测器灵敏度达到。
氢火焰检测器 图片:
氢火焰检测器 图片:

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