JP2759237B2 - Sensitivity adjustment method for inductively coupled plasma mass spectrometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the sensitivity of an inductively coupled plasma mass spectrometer.

[0002]

2. Description of the Related Art When analyzing a solution sample using an inductively coupled plasma mass spectrometer, which is an ultra-trace analysis device, there is a heating vaporization introducing device for introducing the solution sample into plasma. This heating vaporizer is suitable for high-sensitivity measurement.The solution sample to be analyzed is dried and ashed at medium to low temperature to remove the solvent, then vaporized at high temperature, and introduced into the plasma together with argon gas as carrier gas. Is what you do.

[0003] In the heating and vaporizing introduction apparatus, a temperature rising profile for drying, ashing and vaporizing a solution sample plays an important role. There is an optimum heating profile depending on the solution sample to be analyzed, and which heating profile is used is selected according to the elements contained in the solution sample. Then, the solution sample is heated according to the selected heating profile, and the sensitivity of the inductively coupled plasma mass spectrometer is adjusted.

[0004] For the sensitivity adjustment, different kinds of temperature rising profiles each adapted to a simple substance such as Hg, Co, ArO or the like are used. A sensitivity adjustment method using ArO will be described. First, after injecting the solution sample into the electric furnace, the mass number is set to 56, and the solution sample is heated according to the temperature rising profile B for ArO sensitivity adjustment as shown in FIG. First stage B provided in ArO sensitivity adjustment heating profile
_{In step 1} , ArO is detected and sensitivity is adjusted.

[0005]

However, the conventional apparatus for introducing heat vaporization has the following problems. That is, a single adjustment cannot provide sufficient sensitivity that can be used for analysis. In addition, one adjustment requires 1
Since sensitivity can only be adjusted for various types of mass numbers (for example, 56 of ArO), it is difficult to adjust sensitivity to the maximum in a range (5 to 250 amu) that can be measured by an inductively coupled plasma mass spectrometer. Therefore, it is necessary to perform the adjustment at least a plurality of times, which tends to increase the time required for the sensitivity adjustment, and also requires a large number of adjustment samples. Further, in the electric furnace, heating for sensitivity adjustment is repeated, so that the electric furnace tends to deteriorate quickly.

The present invention has been made in view of the above circumstances, and provides a method of adjusting the sensitivity of an inductively coupled plasma mass spectrometer capable of obtaining sufficient sensitivity corresponding to various elements in one adjustment. It is an object.

[0007]

The sensitivity adjusting method of the inductively coupled plasma mass spectrometer according to the present invention is a method for adjusting the sensitivity of a mixed standard solution in which a plurality of types of samples are mixed. Heating is performed with a heating profile having stages, and when a sample is detected at each stage, the sensitivity of the inductively coupled plasma mass spectrometer is adjusted.

[0008]

FIG. 1 is a graph showing a temperature rise profile used in a method of adjusting the sensitivity of an inductively coupled plasma mass spectrometer according to one embodiment of the present invention. FIG. 2 is a graph showing a mass spectrum at the time of sensitivity adjustment. It is a graph superimposed.

In the method for adjusting the sensitivity of the inductively coupled plasma mass spectrometer according to this embodiment, Hg (mass number 202), Ar
The case where a mixed standard solution in which O (mass number 56), Co (mass number 59) and Sr (mass number 88) are mixed will be described.

Here, it is assumed that the sensitivity is adjusted with a temperature rise profile A as shown in FIG. The stage in the temperature rise profile refers to a portion where the temperature rise is slower than other portions. That is, FIG.
In heating profile A shown in the first stage A ₁ is 25
° C to 50 ° C, 2nd stage A ₂ is 100 ° C, 3rd stage A
₃ 1175 ° C., the fourth stage A ₄ is a part of 1600 ° C. to 1700 ° C..

[0011] The heating profile A is input to a control unit for controlling the heating / vaporization introducing device, and the mixed standard solution is injected into an electric furnace constituting a part of the heating / vaporization introducing device.

First, the mass number of the sample to be detected by the inductively coupled plasma mass spectrometer is set to 202. The electric furnace is
Because heating a mixed standard solution according to the heating profile in the first stage A _1, Hg is detected as shown in FIG. Temperature of the electric furnace is appropriately adjust the sensitivity of inductively coupled plasma mass spectrometer while there in the first stage A _1.

When the sensitivity adjustment in the first stage A ₁ is completed, the mass number is set to 56. Since the second stage A ₂ ArO is detected, to adjust the sensitivity of the temperature of the electric furnace is in the second stage A _2. Similarly, the third stage A ₃ sets the mass number to 59 and detects Co to adjust the sensitivity, and the fourth stage A ₄ sets the mass number to 88 to detect Sr and adjusts the sensitivity. I do. This means that the sensitivity of the inductively coupled plasma mass spectrometer was adjusted by the four samples (Hg, ArO, Co, and Sr).

The S / N ratio when the mass spectrometry of Cu is performed by the inductively coupled plasma mass spectrometer whose sensitivity has been adjusted by the above-described method of adjusting the sensitivity of the inductively coupled plasma mass spectrometer according to the present invention, and the conventional sensitivity Table 1 shows the adjustment method, that is, the S / N when the mass spectrometry of Cu was performed by the inductively coupled plasma mass spectrometer in which the sensitivity was adjusted by detecting only ArO.
Shown in

[0015]

[Table 1]

That is, according to the method of adjusting the sensitivity of the inductively coupled plasma mass spectrometer according to the present invention, an improvement of about 2.5 times can be seen.

In this embodiment, four samples, Hg,
Although a mixed standard solution obtained by mixing ArO, Co, and Sr is used, and heating is performed with a temperature rising profile corresponding thereto, a mixed standard solution obtained by mixing other samples may be used. In this case, it goes without saying that heating is performed with a temperature rising profile corresponding to the mixed standard solution.

[0018]

The sensitivity adjusting method for an inductively coupled plasma mass spectrometer according to the present invention is directed to a method of increasing the number of stages corresponding to each sample with respect to a mixed standard solution obtained by mixing a plurality of types of samples. When the sample is detected at each stage by heating with the temperature profile, the sensitivity of the inductively coupled plasma mass spectrometer is adjusted, so that a single sensitivity adjustment can adjust the sensitivity over a wide range. it can. Therefore, the sensitivity can be adjusted in a shorter time and more accurately than the conventional sensitivity adjustment method, and the electric furnace is less deteriorated.

[Brief description of the drawings]

FIG. 1 is a graph showing a temperature rising profile used in a sensitivity adjustment method of an inductively coupled plasma mass spectrometer according to one embodiment of the present invention.

FIG. 2 is a graph in which a mass spectrum at the time of sensitivity adjustment is superimposed on the temperature rising profile.

FIG. 3 is a graph showing a heating profile used in a sensitivity adjustment method of a conventional inductively coupled plasma mass spectrometer.

[Explanation of symbols]

A heating profile A ₁ to A ₄ first through fourth stage

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01J 49/26 G01N 27/62 H01J 49/10

Claims (2)

(57) [Claims] In a method for adjusting the sensitivity of an inductively coupled plasma mass spectrometer in which an object to be analyzed is introduced by a heating and vaporizing introduction apparatus, a mixed standard solution in which a plurality of types of samples are mixed corresponds to each sample. Sensitivity adjustment in an inductively coupled plasma mass spectrometer characterized by adjusting the sensitivity of an inductively coupled plasma mass spectrometer when a sample is detected in each stage by heating with a heating profile having a plurality of stages. Method. 2. The method according to claim 1, wherein the plurality of samples are Hg, ArO, Co
2. The method for adjusting sensitivity of an inductively coupled plasma mass spectrometer according to claim 1, wherein the method comprises four of Sr and Sr.