JPH09199076A - Inductively coupled plasma mass spectrograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with the preparation of a mixed solution and prevent the mingling of a contaminant during the preparation process by spraying fogs with two or more sprayers toward a chamber inner tube. SOLUTION: Blank solutions 14a, 15a are put in sample containers 12a, 12b, and carrier gases are fed from carrier gas feed sections 10 so that the gas flows of sprayers 4 are kept constant respectively. The blank solutions 14a, 15a in the sample containers 12a, 12b are sucked into the sprayers 4 through guide pipes 16 and sprayed into a holder 3 from the sprayers 4 to form a foggy mixed sample. The atomized mixed sample reaches the upper face of a torch section 2 through a chamber 1, and the mixed sample of large grains is discharged to the outside from an waste liquid hole 18. The atomized mixed sample is ionized in the torch section 2 where plasma is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sample introduction device used in an inductively coupled plasma mass spectrometer.

[0002]

2. Description of the Related Art In a conventional sample introduction device for an inductively coupled plasma mass spectrometer, a chamber serving as a sample introduction path is connected to a torch portion for plasma generation, and a sample is atomized on a holder provided at one end of this chamber. It is configured by mounting one atomizing device for atomization, and when a plurality of liquids are sprayed, the liquids are mixed before being sprayed by the atomizer.

[0003]

In the above prior art, when the target element is to be analyzed by the internal standard method,
It is necessary to prepare a mixed solution of a standard solution of the target element and a solution of the internal standard element. In this internal standard method, it was necessary to add a fixed amount of internal standard element to each sample, which required many operations and time.

Further, there is a risk that the accuracy of analysis will be deteriorated due to variations in the amount of addition of the internal standard element in each mixed solution due to the preparation operation and contamination by contaminants in the process. An object of the present invention is to solve the above problems and to obtain a sample introduction device for an inductively coupled plasma mass spectrometer that can easily set a mixing ratio of a mixed solution and can introduce a constant sample amount into a torch part. To do.

[0005]

The sample introduction device for an inductively coupled plasma mass spectrometer adopted by the present invention to achieve the above object sprays mist toward the inner tube of the chamber with two or more sprayers. Characterize things.

Further, the present apparatus is characterized in that the flow rate of the carrier gas connected to each atomizer is independently controlled, and the sum of the flow rates of the carrier gas is made constant.

[0007]

The sample introduction device for an inductively coupled plasma mass spectrometer according to the present invention generates inductively coupled plasma by atomizing each solution with a separate atomizer when a mixed solution of a plurality of solutions is to be analyzed. To introduce to the torch part,
No need to prepare the mixed solution in advance,
In addition, it is possible to prevent variations in the addition amount of each mixed solution due to the preparation operation and to prevent contamination with contaminants during the process.

Further, the present apparatus can independently control the flow rate of the carrier gas connected to each atomizer, and can easily set the mixing ratio of the mixed solution introduced into the torch section. Further, since the sum of the flow rates of the carrier gas can be made constant, the amount of the sample solution introduced into the torch part can be kept constant in the inductively coupled plasma mass spectrometry whose sensitivity greatly depends on the flow rate of the carrier gas.

[0009]

【Example】

[Example 1] The present invention will be described based on Fig. 1 and showing a method for preparing a calibration curve by an internal standard method and a standard addition method.

The internal standard method is one of the methods for preparing a calibration curve in quantitative analysis by an instrument, and is a method for preventing an error due to the influence of other components in the sample to be analyzed. Deviation from the true value due to differences in sample solution viscosity and surface tension, or fluctuations in values due to plasma fluctuations and drifts can be eliminated by using the internal standard method.

In the internal standard method, a fixed amount of internal standard element is added to each standard solution, and the ratio (I _S / I _R ) of the signal intensity (I _S ) of the measured element and the signal intensity (I _R ) of the internal standard element is added. ) Is plotted against the measured elemental concentrations to create a calibration curve. Similarly, an internal standard element is added to the sample solution, and the signal intensity is measured to quantify the measured element.

In the drawing, reference numeral 1 is a chamber, and chamber 1
Is provided with a torch portion 2 for generating inductively coupled plasma, a cylindrical holder 3 is provided at the end of the chamber 1, and the holder 3 is equipped with two atomizers 4, 4. . There are a Scott type and a cyclone chamber as types of the chamber 1, and a coaxial type, a cross flow type, and a Babington type as the types of the sprayer 4, and any type can be used.

The joint surface between the torch portion 2 and the chamber 1 is connected by the clamp 6 so as to prevent leakage.
An O-ring 7 is interposed at the joint between the chamber 1 and the holder 3 to prevent the gas in the chamber 1 from leaking to the outside and keep airtightness. The atomizers 4 and 4 are respectively provided with flowmeters 8 and 8, and carrier gas is supplied from carrier gas supply units 10 and 10, respectively.

Now, in the preparation of the calibration curve for the determination of yttrium Y by the internal standard method using indium In as the internal standard element, the blank solutions 14a and 15a are put into the sample containers 12a and 12b, respectively, and the sprayers 4 and 4 are charged. When the carrier gas is supplied from the carrier gas supply units 10 and 10 so that the gas flow rate is constant at 0.5 l / min, the blank solution 14 in the sample containers 12a and 12b is
a, 15a pass through the introduction pipes 16, 16 and the atomizers 4, 4
It is sucked inside and sprayed into the inside of the holder 3 from the atomizers 4 and 4 to form a mist-like mixed sample.

The atomized mixed sample reaches the upper surface of the torch portion 2 through the chamber 1, but the other large particulate mixed sample is discharged to the outside from the waste liquid hole 18 of the chamber 1. That is, the chamber 1 classifies the atomized sample and supplies the classified sample to the torch unit 2.

On the other hand, the torch unit 2 is usually made of a triple-structured quartz tube, and argon gas is usually supplied from the plasma gas supply hole 19, and the induction coil 20 is supplied with high frequency power (for example, frequency 27.12 MHz, power 1 kW). Is applied, plasma 21 is formed, and the atomized mixed sample is ionized.

Reference numeral 22 is an auxiliary gas supply hole. A mass spectroscope (not shown) measures the Y count rate C _YB and the In count rate C _{InB of the} ionized mixed sample. C _YB and C _InB are Y in the blank solution,
It is the count rate of In. Next, the blank solutions 14a, 15
3 ppb internal standard solution 14b of In was placed in the sample container 12a instead of a, and 1 ppb standard solution 15b of Y was placed in the sample container 12b so that the gas flow rates of the atomizers 4 and 4 were 0.5 l / min respectively. When the carrier gas is supplied from the carrier gas supply units 10 and 10, the In3ppb standard solution 14b in the sample container 12a and the sample container 12 are
The Y1ppb standard solution 15b in b passes through the introduction pipes 16 and 16 and is sucked into the inside of the atomizers 4 and 4, and
Then, it is sprayed into the inside of the holder 3 to form a mist-like mixed sample, which is ionized by the plasma 21.

With respect to the ionized mixed sample, the count rate C _{Y1 of Y} and the count rate C _{In3 of In} are measured by a mass spectrometer. The count rate of Y1ppb (C _Y1 -C _YB) and I
It is the ratio of count rate _{n3ppb (C In3 -C InB) (} C
Plotted against _{YI -C YB) / (C In3} -C InB) the Y concentration 1 ppb.

Next, in place of the Y1ppb standard solution 15b, the Y2ppb standard solution 15c is put in the sample container 12b,
The In3ppb internal standard solution 14b is directly placed in the sample container 12b. When the gas is supplied from the carrier gas supply units 10 and 10 so that the gas flow rates of the atomizers 4 and 4 are constant at 0.5 l / min, respectively, the sample container 12a is obtained.
In3ppb internal standard solution 14b and sample container 12b
The Y2ppb standard solution 15c in the inside passes through the introduction pipes 16 and 16 and is sucked into the inside of the sprayers 4 and 4, and is sprayed from the sprayers 4 and 4 into the inside of the holding body 3 to form a mist-like mixed sample,
It is ionized by the plasma 21.

A mass spectroscope measures the count rate C _{Y2 of Y} and the count rate C _{In3 of} In of the ionized mixed sample. The count rate of Y2ppb (C _Y2 -C _YB) and I
It is the ratio of count rate _{n3ppb (C In3 -C inB) (} C
Plotted against _{Y2 -C YB) / (C In3} -C InB) the Y concentration 2 ppb.

Next, in place of the Y2ppb standard solution 15c, the Y3ppb standard solution 15d is put in the sample container 12b,
The In3ppb internal standard solution 14b is directly placed in the sample container 12a. When the gas is supplied from the carrier gas supply units 10 and 10 so that the gas flow rates of the atomizers 4 and 4 are constant at 0.5 l / min, respectively, the sample container 12a is obtained.
In3ppb internal standard solution 14b and sample container 12b
The Y3ppb standard solution 15d in the inside passes through the introduction tubes 16 and 16 and is sucked into the inside of the nebulizers 4 and 4, and is ejected from the nebulizers 4 and 4 into the inside of the holding body 3 to form a mist-like mixed sample,
It is ionized by the plasma 21.

A mass spectroscope measures the count rate C _{Y3 of Y} and the count rate C _{In3 of} In of the ionized mixed sample. The count rate Y3ppb and (C _Y3 -C _YB) I
It is the ratio of count rate _{n3ppb (C In3 -C InB) (} C
Plotted against _{Y3 -C YB) / (C In3} -C INB) the Y concentration 3 ppb.

In this way, a calibration curve is prepared by plotting the ratio of the Y and In count rates to the Y concentration. Next, Y3p
Instead of the pb standard solution 15d, the unknown Y concentration sample solution 15e is placed in the sample container 12b, and the In3ppb internal standard solution 14b is placed in the sample container 12a as it is.

The gas flow rates of the atomizers 4 and 4 are 0.5 respectively.
Carrier gas supply unit 1 so as to maintain a constant l / min
When gas is supplied from 0 and 10, I in the sample container 12a
n3ppb internal standard solution 14b and Y in sample container 12b
The unknown concentration sample solution 15e passes through the introduction tubes 16 and 16,
It is sucked into the inside of the atomizers 4 and 4, and is sprayed from the atomizers 4 and 4 into the inside of the holder 3 to become a mist-like mixed sample, which is ionized by the plasma 21.

With respect to the ionized mixed sample, the Y counting rate C _YX and the In counting rate C _In3 are measured by a mass spectrometer. _{Then, (C YX -C YB) /} (C In3 -C InB) look, the Y concentration giving its value in the calibration curve, the concentration of Y in the Y concentration unknown sample 15e.

[Example 2] The standard addition method is a method of determining the concentration of a target component in a sample by obtaining signal intensities of the sample solution as it is and a sample solution in which the standard solution is added stepwise. Yes, it is useful when the slope of the obtained straight line is different from that of the calibration curve.

In the quantitative determination of Y by the standard addition method, blank solutions 14a and 1 were placed in the sample containers 12a and 12b, respectively.
5a, and the gas flow rates of the atomizers 4 and 4 are 0.5 respectively.
Carrier gas supply unit 1 so as to maintain a constant l / min
When gas is supplied from 0 and 10, the sample containers 12a, 12
The blank solutions 14a and 15a in b are introduced into the introduction tubes 16 and 16
Through the inside of the sprayer 4, 4 is sucked into the sprayer 4, 4
4 is injected into the inside of the holder 3 to form a mist-like mixed sample.

The atomized mixed sample reaches the upper surface of the torch portion 2 through the chamber 1, but the other large particulate mixed sample is discharged from the waste liquid hole 18 of the chamber 1. On the other hand, the torch unit 2 is usually made of a triple-structured quartz tube, and gas is supplied from the plasma gas supply hole 19,
High frequency power (eg, frequency 27.1) is applied to the induction coil 20.
By applying 2 MHz and power of 1 kW, plasma 21 is formed and the atomized mixed sample is ionized.

A mass spectroscope (not shown) measures the Y count rate C _{YB of the} ionized mixed sample. Next, instead of the blank solution 14a, the sample container 1
The Y unknown sample solution 14c is put in 2a, the blank solution (Y0ppb standard solution) 15a is kept put in the sample container 12b, and the gas flow rates of the sprayers 4 and 4 are 0.5 respectively.
Carrier gas supply unit 1 so as to maintain a constant l / min
When gas is supplied from 0 and 10, Y in the sample container 12a
The unknown sample solution 14c and the blank solution 15a in the sample container 12b are sucked into the inside of the atomizers 4 and 4 through the introduction pipes 16 and 16 and are sprayed from the atomizers 4 and 4 into the inside of the holder 3 to be atomized. It becomes a mixed sample and is ionized by the plasma 21.

The count rate C _{M0 of} Y of the ionized mixed sample is measured by a mass spectrometer. Then, it plotted against the addition of count rate (C _M0 -C _YB) Y standard concentration 0 ppb.

Next, the Y unknown sample solution 14d in the sample container 12a is left as it is, and Y1ppb is used in the sample container 12b instead of the blank solution (Y0ppb standard solution) 15a.
When 15 g of the standard solution was charged and the gas was supplied from the carrier gas supply units 10 and 10 so that the gas flow rates of the atomizers 4 and 5 were constant at 0.5 l / min, respectively, the sample container 1
Y unknown sample solution 14c in 2 and Y1 in sample container 12b
15 g of the ppb standard solution is sucked into the inside of the atomizers 4 and 4 through the introduction pipes 16 and 16 and injected into the inside of the holder 3 from the atomizers 4 and 4 to become a mist-like mixed sample, which is ionized by the plasma 21. It

The count rate C _{M1 of} Y of the ionized mixed sample is measured by a mass spectrometer. Then, it plotted against the addition of count rate (C _M1 -C _YB) Y standard concentration 1 ppb.

Next, the Y unknown sample solution 14c in the sample container 12a is left as it is, and Y1p is added to the sample container 12b.
Y2ppb standard solution 15 instead of 15g of pb standard solution
h, and the gas flow rates of the atomizers 4 and 4 are 0.5, respectively.
Carrier gas supply unit 1 so as to maintain a constant l / min
When gas is supplied from 0 and 10, Y in the sample container 12a
The unknown sample solution 14c and the Y2ppb standard solution 15h in the sample container 12b pass through the introducing pipes 16 and 16, and the atomizer 4 is supplied.
4 is sprayed into the inside of the holder 3, and is sprayed from the sprayers 4 and 4 into the inside of the holder 3 to form a mist-like mixed sample, which is ionized by the plasma 21.

The count rate C _{M2 of} Y of the ionized mixed sample is measured by a mass spectrometer. Then, it plotted against the addition of count rate (C _M2 -C _YB) Y standard concentration 2 ppb.

Next, the Y unknown sample solution 14c in the sample container 12a is left as it is, and Y2p is added to the sample container 12b.
Y3ppb standard solution 15 instead of pb standard solution 15h
i, and the gas flow rates of the atomizers 4 and 4 are 0.5, respectively.
Carrier gas supply unit 1 so as to maintain a constant l / min
When gas is supplied from 0 and 10, Y in the sample container 12a
The unknown sample solution 14c and the Y3ppb standard solution 15i in the sample container 12b pass through the introduction pipes 16 and 16, and the atomizer 4 is supplied.
4 is sprayed into the inside of the holder 3, and is sprayed from the sprayers 4 and 4 into the inside of the holder 3 to form a mist-like mixed sample, which is ionized by the plasma 21.

The count rate C _{M3 of} Y of the ionized mixed sample is measured by a mass spectrometer. Then, a plot is made against the Y standard solution concentration of 3 ppb to which the counting rate (C _M3 -C _YB ) is added.

The value of the intersection of the straight line drawn by the above four plots and the horizontal axis is taken as the concentration of the Y concentration unknown sample solution. The flow meters 8 and 8 are connected to the control device 23,
The flow rate of the carrier gas connected to each atomizer can be controlled independently, and the sum of the flow rates of the carrier gas can be made constant.

Although two sprayers are used in the above embodiment, three or more sprayers may be used.

[0039]

INDUSTRIAL APPLICABILITY The present invention uses a plurality of atomizers in a sample introduction device for an inductively coupled plasma mass spectrometer, and can independently control the flow rate of carrier gas connected to each atomizer, and further, the flow rate of carrier gas. Since the structure is such that the sum of can be made constant, it has the following effects.

(1) The operation and time for preparing the mixed solution can be omitted. (2) It is possible to prevent variations in the addition amount of each mixed solution due to the mixed solution preparation operation, and to prevent contamination with contaminants during the preparation process.

(3) The mixing ratio of the mixed solution introduced into the torch part can be easily set, and the amount of the sample solution introduced into the torch part can be kept constant.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 chamber 2 torch part 3 holder 4 atomizer 6 clamp 7 O-ring 8 flowmeter 10 carrier gas supply part 12a sample container 12b sample container 14 each sample 16 introduction pipe 18 waste liquid hole 19 plasma gas supply hole 20 induction coil 21 plasma 22 auxiliary Gas supply hole 23 Control device

Claims (4)

[Claims] 1. An inductively coupled plasma mass spectrometer in which an atomized sample is supplied to the torch part by connecting a chamber serving as a sample introduction path to the torch part for generating the inductively coupled plasma, and an inner tube of the chamber. An inductively coupled plasma mass spectrometer characterized by spraying mist with two or more sprayers toward. 2. The inductively coupled plasma mass spectrometer according to claim 1, wherein the flow rate of the carrier gas connected to each atomizer is independently controlled. 3. The inductively coupled plasma mass spectrometer according to claim 1, wherein the sum of the flow rates of the carrier gas is constant. 4. An atomized sample is classified, and one atomizer provided in a chamber for supplying the classified sample to the torch section is used to measure an internal standard element having a constant concentration. A certain amount of the standard solution is atomized, and the other atomizer provided in the chamber atomizes a certain amount of the standard solution having a measurement concentration of a predetermined measurement element, and the one atomizer is used. While keeping the concentration and the amount of atomization of the internal standard solution to be atomized, the concentration of the measurement element of the standard solution to be atomized is changed and atomized to a certain amount on the other side, and the mass spectrometry of each concentration of the measurement element of the standard solution is counted. A method for inductively coupled plasma mass spectrometry, characterized in that a ratio between a rate and a counting rate of internal standard element mass spectrometry of an internal standard solution is obtained, and a calibration curve is obtained based on the ratio.