JPH052846Y2 - - Google Patents

Description

[Detailed explanation of the invention] (a) Industrial application field This invention is a high-frequency plasma emission spectrometer, especially a high-frequency inductively coupled plasma emission spectrometer (hereinafter referred to as ICP).
It is abbreviated as. ), in detail, it relates to an improved ICP that enables quick and easy analysis of elemental impurities contained in gaseous samples.

(b) Conventional technology As shown in Fig. 3, conventional ICP supplies a solution sample and a carrier gas into a nebulizer 3 from a solution sample supply path 1 and a carrier gas supply path 2, respectively, and atomizes the solution sample. A sample is introduced into a high-frequency plasma generation section (hereinafter abbreviated as generation section) 4, and elemental impurities contained therein are detected by a spectrophotometry section 5.
This is what we will analyze.

However, in this ICP, the amount of atomized sample introduced into the generation section 4 varies greatly depending on the degree of atomization of the solution sample, making plasma generation extremely unstable.

(c) Purpose This invention was developed in view of the above circumstances, and its main purpose is to configure the gas sample so that it can be introduced into the generation section, to control the amount introduced, and to change the type of gas sample. The object of the present invention is to enable quick and simple qualitative and quantitative analysis of elemental impurities contained in a gas sample, regardless of the situation.

(D) Configuration This device is a high-frequency plasma emission spectrometer, which includes a cylindrical high-frequency plasma generation section, a spectrophotometry section that measures light emitted from the plasma generation section, and a cylindrical interior of the plasma generation section. A mixed gas introduction path equipped with a gas mixer that mixes and introduces a gas sample and a carrier gas, and a branch connection to the introduction side end of this introduction path, and a flow rate detection sensor and a flow rate control means in order from this branch connection side, respectively. 1 who intervened
a gas sample supply path and a carrier gas supply path, and a control means for controlling the flow rate control means, the control means controlling the gas sample introduced into the gas mixer based on the detection signal of the flow rate detection sensor The present invention is characterized in that the flow rate control means is controlled so that the total amount of carrier gas introduced is constant, and the introduction of the gas sample is stopped in response to a photometry end signal from the spectrophotometer.

That is, this device mixes the gas sample and carrier gas supplied from the gas sample supply path and the carrier gas supply path, respectively, in a gas mixer, and introduces this mixed gas into the generation section. The amount of sample supplied and the supply itself are controlled by a flow rate control means.

(E) Example This invention will be described in detail below based on the example shown in FIGS. 1 and 2.

Note that this invention is not limited to this.

FIG. 1 shows a high frequency inductively coupled plasma emission spectrometer 8. As shown in FIG. 9 is a spectrophotometry section, 10 is a high frequency plasma generation section, and 11 is a sample introduction section. The generating section 10 consists of a cylindrical torch section 12 and two plasma generating gas introduction passages 13, 13 provided on the cylindrical wall of the torch section. be. The wavelength range used by the spectrophotometer 9 is approximately 150 nm to 900 nm.

As shown in FIG. 2, the sample introduction section 11 includes a mixed gas introduction path 15 for introducing a gas sample and a carrier gas into the cylinder of the generation section 10 from its lower end, and a gas mixer at the gas introduction side end of this introduction path. It mainly consists of a pair of gas sample supply passages 17 and carrier gas supply passages 18 which are branched and connected via a gas sample supply passage 16 . Note that there may be a plurality of sets of both the gas supply paths 17 and 18. The gas sample supply path 17 and the carrier gas supply path 18 are provided with flow path opening/closing valves 19, 20, flow control valves (flow controllers) 21, 22, and flow rate detection sensors (flow meters) 23, in order in the respective gas supply directions. 24 is interposed, and a flow path opening/closing valve 25 is interposed in the mixed gas introduction path 15. Note that the three flow path opening/closing valves 19, 20, and 25 are composed of electromagnetic valves. In addition, two flow path opening/closing valves 19, 20 and a flow control valve 2 are provided.
1 and 22 constitute flow control means 26 and 27.

The above-mentioned on-off valves 19, 20, 25, flow control valve 2
1, 22, a control means 2 for controlling the operation of the flow rate control valves 21, 22 and the flow path opening/closing valves 19, 20, 25 in the flow rate detection sensors 23, 24 and the spectrophotometer 9;
8 are electrically connected. A preferred example of this control means is a sequencer.

Next, the operation of the device 8 will be explained.

First, the type of carrier gas to be used is determined by taking into account the characteristics of the gas sample. Note that various gases such as argon, nitrogen, and cyan gas are used as the gas sample.

Next, the plasma 14 is turned on in the same manner as in the prior art. Then, the flow path opening/closing valve 20 is opened and operated to supply carrier gas to the carrier gas supply path 18, for example.
Introduce 1l/min. Next, the flow path opening/closing valve 19 is opened based on the control signal from the control means 28, and at the same time the flow rate control valve 21 is controlled to mix the gas sample at a predetermined flow rate, for example, 0.1 l/min from the gas sample supply path 17. When introduced into the gas supply path 15,
Based on the control signal of the control means 28, the flow rate control valve 2
2 is activated to reduce the flow rate of the carrier gas introduced into the mixed gas supply path 15 to 0.9 l/min, thereby making the flow rate introduced into the mixed gas supply path 15 match the initial amount of carrier gas introduced. In this state, the plasma 14 is photometered and the gas sample is analyzed.

Next, when photometry is completed, the flow path opening/closing valve 19 is closed based on the control signal from the control means 28 to stop the introduction of the gas sample, and at the same time the flow rate control valve 22
is operated in a controlled manner to restore the carrier gas flow rate to its original flow rate.

The above steps are repeated to analyze each gas sample to be analyzed. In this case, not only is it possible to prevent the generation of unstable plasma that occurs when a solution sample is used in the conventional method during spectroscopy of the plasma 14, but also the total amount of introduced gas sample and carrier gas can be controlled at a constant level. Therefore, it is possible to generate stable plasma, and the stabilization is further improved to enable highly accurate qualitative and quantitative analysis. In addition, this device 8
Analysis can be performed both off-line and online, such as during process control in manufacturing processes.In addition, a gas chromatograph can be installed on the gas supply side of the sample introduction section 11 to separate and analyze the exhaust gas discharged from the gas chromatograph. can also be used.

(f) Effect This device mixes a carrier gas and a gas sample, introduces the mixed gas into the high-frequency plasma generation section, and controls the total amount of both gases to be introduced at a constant level during the introduction and when the plasma is turned on. This structure further improves the stabilization of plasma through the use of gas samples, enabling highly accurate qualitative and quantitative analysis.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of an embodiment of the high-frequency plasma emission spectrometer according to this invention, and FIG.
This explanatory diagram of the main part configuration, FIG. 3, is a diagram corresponding to FIG. 1 of the conventional example. 8... High frequency plasma inductively coupled optical emission spectrometer (ICP), 9... Spectrophotometry section, 10... High frequency plasma generation section, 15... Mixed gas introduction path, 16...
Gas mixer, 17... Gas sample supply path, 18...
Carrier gas supply path, 26, 27...Flow rate control means, 28...Control means.

Claims (1)

[Claims for Utility Model Registration] 1. A cylindrical high-frequency plasma generation section, a spectrophotometry section that measures light emitted from the plasma generation section, and a gas sample and carrier gas mixed in the cylinder of the plasma generation section. A mixed gas introduction path equipped with a gas mixer for introducing gas into the gas mixture, and one or more sets of gases connected in a branch to the introduction side end of this introduction path and each having a flow rate detection sensor and a flow rate control means interposed in order from this branch connection side. The control means includes a sample supply path, a carrier gas supply path, and a control means for controlling the flow rate control means, and the control means controls the total amount of the gas sample and carrier gas introduced into the gas mixer based on the detection signal of the flow rate detection sensor. A high-frequency plasma emission spectrometer, characterized in that the flow rate control means is controlled so that the amount introduced is constant, and the introduction of the gas sample is stopped in response to a photometry end signal from the spectrophotometer. 2. The high-frequency plasma emission spectrometer according to claim 1, wherein the flow rate control means comprises a flow rate control valve on the side of the flow rate detection sensor and a flow path opening/closing valve on the both gas supply sides from the flow rate control valve.