JPH08313441A - Inductively coupled plasma atomic emission spectrometer - Google Patents

Abstract

PURPOSE: To provide an inductively coupled plasma atomic emission spectrometer which enables a measuring person to perceive a drop in or stopping of the amount of a sample and a carrier gas introduced as caused by the generation of clogging by monitoring the condition of the clogging of a nebulizer and a plasma torch. CONSTITUTION: A sample solution 2 nebulized by a nebulizer 1 is introduced to a plasma torch 8 via a spray chamber 7. A gas flow rate sensor 6 is mounted on a carrier gas passage 22 between a gas control section 11 and the nebulizer 1 and a flow rate signal from the gas flow rate sensor 6 is fetched into a data processing section 19 to be collated with a reference value stored previously. When the intensity of the flow rate signal becomes smaller than the reference value in case of the clogging of the nebulizer 1 or an injector pipe 23, an indication to the effect, the occurrence of the clogging, is shown on a warning display section 21. In addition, outputs of the gas control section 11 and a high frequency power source 15 are stopped to extinguish a plasma automatically.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency inductively coupled plasma optical emission spectrometer.

[0002]

2. Description of the Related Art In a conventional high frequency inductively coupled plasma emission spectrometer, a pneumatic nebulizer is generally used for atomizing a sample solution and introducing it into plasma when measuring the sample solution.

There are various nebulizer atomization methods, and the method shown in FIG. 3 will be described as an example.

FIG. 3 is a sectional view of a structure in which a concentric nebulizer and a spray chamber are combined in a conventional high frequency inductively coupled plasma optical emission spectrometer.

In FIG. 3, 1 is a concentric nebulizer, 2 is a sample solution, 3 is a drain, 4 is a carrier gas capillary, 5 is a sample solution introducing capillary, 7 is a spray chamber, and 12 is a carrier gas.

In the nebulizer 1, the sample solution 2 supplied through the sample solution introducing capillary 5 is applied with the principle of atomization, and a carrier gas 12 which normally uses argon gas is used.
It is sucked and atomized by and sprayed in the spray chamber 7.

The sprayed sample solution 2 is introduced into a plasma torch, excited, emits light, and is subjected to spectroscopic analysis.

The atomized sample solution 2 fed into the plasma torch from the spray chamber 7 is a small amount of the sample solution introduced into the spray chamber 7 from the nebulizer 1, and most of it is discharged as the drain 3. . At this time,
The spray chamber 7 has a structure sealed by the drain 3.

The tip opening from which the atomized sample solution 2 is sprayed from the nebulizer 1 has a small diameter, and a sample solution having a high viscosity or a sample solution in which a solid content is likely to be deposited easily causes clogging and causes a measurement error. It becomes a factor.

On the other hand, the plasma torch generally has a triple tube structure. FIG. 4 is a sectional view of a plasma torch in a conventional high frequency inductively coupled plasma optical emission spectrometer.
A plasma gas 13 flows in the outermost side, an auxiliary gas 14 in the middle, and a carrier gas 12 containing a mist-like or gaseous sample flows in the innermost side. The injector tube 23 for flowing the innermost carrier gas generally has a diameter of the tip opening of 1 mm or less, and like the nebulizer 1, a sample solution having a high viscosity or a sample solution in which a solid content is likely to be precipitated easily causes clogging, This will cause a measurement error.

Conventionally, for fluctuations in the pressure in the spray chamber, means for detecting the pressure in the spray chamber,
There has been proposed a technique of providing a control means for making the detected pressure in the chamber constant.

Regarding this, Japanese Patent Laid-Open No. 1-250045
There is a technique described in Japanese Patent Publication.

However, this is for detecting the pressure fluctuation in the chamber due to the fluctuation of the drain head in the spray chamber, and it is possible to detect when the injector tube of the plasma torch is clogged, but it is possible to detect it. When the opening is clogged, the pressure in the spray chamber changes little and cannot be detected.

[0014]

In the injector tube of the nebulizer and the plasma torch used in the conventional high frequency inductively coupled plasma optical emission analyzer, since the diameter of the tip opening is small, a highly viscous sample solution or solid content is deposited. If the sample solution is easy, clogging is likely to occur. If the tip opening of the nebulizer or the injector tube is clogged, the sample solution may not be introduced into the plasma or the introduction amount may decrease. Therefore, if the measurer continues the measurement without noticing the clogging, the emission intensity of the target element may change, which may cause a measurement error.

Further, when the supply of the carrier gas to the plasma is stopped due to the clogging, there is a risk that the plasma flame may be lowered to melt the plasma torch.

An object of the present invention is to enable a measurer to easily confirm that the nebulizer and the injector tube are not clogged and the sample solution and the carrier gas are normally guided to the high frequency inductively coupled plasma. The object is to provide a high frequency inductively coupled plasma optical emission spectrometer which does not have a measurement error.

[0017]

[Means for Solving the Problems] In order to achieve the purpose,
The configuration of the high frequency inductively coupled plasma optical emission spectrometer according to the present invention is a high frequency inductively coupled plasma in which a sample solution atomized by a nebulizer is fed into a high frequency inductively coupled plasma by a carrier gas to perform an emission analysis of elements contained in the sample. The optical emission analyzer is provided with means for monitoring whether the nebulizer or the plasma torch tube is clogged with the sample.

The means for monitoring whether or not the nebulizer or the plasma torch tube is clogged with the sample is configured to detect a change in the flow rate of the carrier gas that sends the sample to the high frequency inductively coupled plasma.

The means for monitoring whether the nebulizer or the plasma torch tube is clogged with the sample is configured to detect the pressure change of the carrier gas that sends the sample to the high frequency inductively coupled plasma.

[0020]

According to the present invention, the means for monitoring whether or not the nebulizer or the plasma torch tube is clogged with the sample is provided, so that the measurer can check the abnormality of the introduction of the sample solution and the carrier gas into the high frequency inductively coupled plasma. It is possible to easily detect, it is possible to prevent erroneous measurement results from being adopted, and it is possible to prevent the risk of melting the plasma torch.

[0021]

Embodiments of the present invention will be described below with reference to FIGS.

[Embodiment 1] FIG. 1 is a block diagram showing a configuration of an embodiment of a high frequency inductively coupled plasma optical emission spectrometer of the present invention, and FIG. 2 is a high frequency inductively coupled plasma optical emission spectrometer of the embodiment of FIG. 2 is a sectional view of the concentric nebulizer in FIG.

In FIG. 1, the sample solution introducing capillary tube 5 has a concentric nebulizer 1 at one end and a sample solution 2 at the other end.

The nebulizer 1 has a gas control unit 1
Argon gas is introduced as carrier gas 12 from 1.

The concentric nebulizer 1 is one type of pneumatic nebulizer, and as shown in FIG. 2, a structure for arranging a sample introduction capillary 5 inside a carrier gas capillary 4 coaxially with the capillary. Has become.

The sample solution 2 sucked by the negative pressure generated by the flow of the carrier gas 12 is sprayed from the tip of the sample solution introducing capillary 5 and atomized. The atomized sample solution 2 is guided to the plasma torch 8 via the spray chamber 7.

A gas flow sensor 6 is attached to the carrier gas flow path 22 between the gas control unit 11 and the nebulizer 1 so as to detect the flow rate of the carrier gas.

A high frequency induction coil 9 is installed on the outer periphery of the plasma torch 8. The high frequency induction coil 9 has a 27 MHz or 40 MHz output from a high frequency power supply 15 and outputs 1-2.
A high frequency power of about kW is applied.

The plasma torch 8 has a gas control unit 1
1, the argon gas is introduced as the plasma gas 13 and the auxiliary gas 14, and the inductively coupled plasma 10 is formed by the high frequency power.

The atomized sample solution 2 which has passed through the spray chamber 7 by the carrier gas 12 is a plasma torch 8.
Is introduced into the plasma 10.

The plasma 10 is at a high temperature, in which the sample solution 2 is decomposed, and the contained element produces an emission line having a wavelength peculiar to each element.

These emitted lights are dispersed by the spectroscope 16, and the emission intensity of the emission line of a specific wavelength corresponding to a predetermined element is taken out as an electric signal by the photomultiplier tube 17. This electric signal is converted into a digital amount by the analog-digital converter 18 and taken into the data processing unit 19.

The data processing section 19 stores in advance the relational expression between the sample concentration and the emission intensity for this element to be measured, and the relational expression of the element in the sample solution 2 is used from the incorporated emission intensity. The density is calculated and displayed on the density display unit 2.

The flow rate signal from the gas flow rate sensor 6 is also taken into the data processing section 19 and collated with a reference value stored in advance. When the flow rate of the carrier gas into the plasma is reduced or stopped due to the clogging of the nebulizer 1 or the injector pipe 23 and the flow signal intensity becomes smaller than the reference value, the nebulizer 1 or the injector pipe is displayed on the warning display unit 21. A message indicating that the clog 23 has occurred is displayed and can be detected by the measurer.

Further, at this time, the data processing section 19 stops the output of the gas control section 11 and the high frequency power supply 15 to automatically extinguish the plasma.

In this embodiment, the gas flow rate sensor detects a change in the flow rate of the carrier gas due to the clogging of the nebulizer 1 or the injector pipe 23 to monitor the clogging state, but a pressure sensor is used instead of the flow rate sensor. The clogging may be determined by the pressure change on the carrier gas supply side due to the clogging. In this case, if the nebulizer 1 or the injector pipe 23 is clogged, the pressure in the carrier gas flow path 22 between the gas control unit 11 and the nebulizer 1 rises, so that the data processing unit 19 detects that the pressure signal strength from the pressure sensor is high. When the value becomes larger than the reference value stored in advance, the warning display section 21 displays that the nebulizer 1 or the injector pipe 23 is clogged, and the output of the gas control section 11 and the high frequency power supply 15 is stopped. Then the plasma is extinguished automatically.

In this embodiment, when the nebulizer or the injector pipe is clogged, an indication that clogging has occurred is displayed on the warning display portion, so that the operator can easily detect the abnormal phenomenon and It is possible to prevent the risk of adopting the measured result and to prevent melting damage of the plasma torch.

[0038]

According to the present invention, it is possible to provide a high frequency inductively coupled plasma optical emission analyzer without a measurement error by allowing a measurer to easily confirm a clogging condition of a nebulizer or an injector pipe. it can.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a high frequency inductively coupled plasma optical emission spectrometer according to the present invention.

FIG. 2 is a sectional view of a concentric nebulizer in the high frequency inductively coupled plasma emission spectrometer of the embodiment of FIG.

FIG. 3 is a cross-sectional view of a structure in which a concentric nebulizer and a spray chamber are combined in a conventional high frequency inductively coupled plasma optical emission spectrometer.

FIG. 4 is a sectional view of a plasma torch in a conventional high frequency inductively coupled plasma emission spectrometer.

[Explanation of symbols]

1 ... Nebulizer, 2 ... Sample solution, 3 ... Drain, 4,5
... capillary, 6 ... gas flow rate sensor, 7 ... spray chamber, 8 ... plasma torch, 9 ... high frequency induction coil, 1
0 ... Inductively coupled plasma, 11 ... Gas control part, 12 ... Carrier gas, 13 ... Plasma gas, 14 ... Auxiliary gas, 1
5 ... High frequency power source, 16 ... Spectrometer, 17 ... Photomultiplier tube,
18 ... Analog-digital converter, 19 ... Data processing part, 20 ... Concentration display part, 21 ... Warning display part, 22 ... Carrier gas flow path, 23 ... Injector tube.

Claims (4)

[Claims] 1. A sample solution atomized by a nebulizer,
In a high frequency inductively coupled plasma optical emission spectrometer for performing an emission analysis of elements contained in the sample solution by feeding into the high frequency inductively coupled plasma by a carrier gas, whether the nebulizer or the plasma torch tube is clogged with the sample solution A high frequency inductively coupled plasma optical emission spectrometer equipped with a means for monitoring. 2. The high frequency inductively coupled plasma optical emission spectrometer according to claim 1, wherein the monitoring means is configured to detect a flow rate change of a carrier gas which sends the sample solution to the high frequency inductively coupled plasma. 3. The high frequency inductively coupled plasma optical emission spectrometer according to claim 1, wherein the monitoring means is configured to detect a pressure change of a carrier gas which sends the sample solution to the high frequency inductively coupled plasma. 4. A sample solution atomized by a nebulizer,
In a high frequency inductively coupled plasma optical emission spectrometer for performing emission analysis of an element contained in the sample by feeding into the high frequency inductively coupled plasma by a carrier gas, it is detected that the nebulizer or the plasma torch tube is clogged with the sample solution. A high-frequency inductively coupled plasma optical emission spectrometer equipped with a means for automatically extinguishing the plasma.