JPH0736325B2 - High frequency inductively coupled plasma / mass spectrometer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a high-frequency inductively coupled plasma / mass spectrometer that combines a high-frequency inductively coupled plasma and a mass spectrometer.

<Prior art> A high-frequency inductively coupled plasma / mass spectrometer uses a high-frequency inductively-coupled plasma to excite a sample, and guides the generated ions to a mass spectrometer through an interface consisting of a nozzle and a skimmer to measure a specific mass. The element to be measured in the sample is analyzed by electrically detecting only the ions. Further, the sample is sent from a sample tank to a nebulizer for atomizing the sample to be an aerosol sample, and then sent to the inner chamber of the plasma torch by argon gas. The sample introduced in this manner is excited by the high frequency inductively coupled plasma as described above, and the generated ions are detected by the mass spectrometer detection unit such as a quadrupole mass filter through an interface including a nozzle and a skimmer. Based on the detection signal, a mass spectrum is drawn on the display unit such as a recorder to analyze the element to be measured in the sample. By the way, there are qualitative analysis and quantitative analysis in the analysis of the element to be measured, and in order to perform the quantitative analysis, the quantitative analysis is carried out by using a calibration curve prepared using standard solutions having plural kinds of concentrations. Multi-inspection calibration curve method, standard addition method for extrapolating a calibration curve created by adding measured elements of known concentrations to multiple amounts of concentrations in the measured solution to determine the measured elements in the measured solution,
Alternatively, one of the internal standard methods was used in which an internal standard element of known concentration was added to both the solution to be measured and the standard solution to obtain the element to be measured in the solution to be measured from the ratio of the internal standard element and the element to be measured. .

<Problems to be Solved by the Invention> However, in the multi-check calibration curve method, a calibration curve must be prepared by preparing a plurality of types (usually 5 to 6 types) of standard solutions having different concentrations. The method has a drawback that a known amount of internal standard element has to be added to all samples and standard solutions, and that preparation and the like are complicated. In addition, the above standard addition method must be added to all measured solutions with a concentration difference of the target element (measured element) such as 1 ppm, 2 ppm, 3 ppm, and 5 ppm. It had the drawback of being even more complicated.

The present invention has been made in view of the drawbacks of the conventional example, and an object thereof is to provide a high-frequency inductively coupled plasma mass spectrometer capable of easily performing any of the multi-check calibration curve method, the standard addition method, and the internal standard method. To provide.

<Means for Solving Problems> A feature of the present invention that solves the above problems is that in a high-frequency inductively coupled plasma mass spectrometer, the number of revolutions of a motor is changed by a computer according to the type of quantitative analysis method. There are various changes.

<Example> Hereinafter, the present invention will be described in detail with reference to the drawings. The figure is a configuration explanatory view of an embodiment of the present invention, in which 1a is a tank for storing the sample, 1b is a tank for storing a solvent such as pure water, 2a is for sending the sample, for example A pump made of a peristaltic pump, 2'a is a motor for rotating the pump 2a, 2b is a pump for sending a solvent, for example, a pump made of a peristaltic pump, 2'b is a motor for rotating the pump 2b, and 3 is a motor 2'a. , A computer for controlling the driving of 2'b, 4 is a mixer for mixing the sample sent from the pump 2a and the solvent sent from the pump 2b, 5 is a nebulizer for atomizing the sample into an aerosol sample, 6 Outermost room 6a, outer room 6
b, and a plasma torch having, for example, a triple tube structure having an inner chamber 6c, 7a is an argon gas supply source, 7b is a pressure regulator for adjusting the pressure of the argon gas delivered from the supply source 7a, 8
Is a high-frequency inductively coupled plasma, 9 is a high-frequency induction coil, 10 is a high-frequency power source for supplying high-frequency energy to the high-frequency induction coil 9, 11 is a nozzle, 12 is a skimmer, 13 is a fore chamber, 14 is the inside of the fore chamber 13, for example 1 torr. Vacuum pump for sucking up to 15, a center chamber, 16 a vacuum pump for sucking up to 10 ^-2 torr. In the center chamber 15, 17 for example a pole such as a quadrupole mass filter, 18 for a rear chamber, 19 for A vacuum pump for sucking the inside of the rear chamber 18 to, for example, 10 ⁻⁴ torr., 20 is a secondary electron multiplier, and 21 is a signal processing unit such as a microcomputer. An ion lens may be provided in the center chamber 15. By the way, the multi-inspection curve method is performed as follows in the embodiment of the present invention. That is, for example, 10 ppm Ni standard solution is put in the sample tank 1a, and pure water, for example, is put in the solvent tank 1b. After that, when the rotation speed ratio of the motor 2'b and the motor 2'a is changed according to a command from the computer 3, for example, (5: 5) → (6: 4) → (7: 3) → (8: 2), The total amount of the sample supplied from the mixer 4 to the nebulizer 5 is constant, and the Ni concentration in the sample is 5 ppm → 4 ppm → 3 ppm →
It will change to 2ppm. A multi-inspection curve can be created by plotting such changes in the concentration of the Ni standard solution on the horizontal axis and the magnitude of each detection signal on the vertical axis. Therefore, for example, a calibration curve can be prepared only by using one Ni standard solution of 10 ppm, and the quantitative analysis of the element to be measured can be easily and accurately performed using this calibration curve. The internal standard method is performed as follows in the embodiment of the present invention. That is, the sample tank 1a
Solution to be measured and standard solution (for example, pure water containing 10ppm Ni)
Are sequentially exchanged, and a reagent having an internal standard element of known concentration (for example, 20 ppm scandium) is placed in the solvent tank 1b. After that, if the rotation speed ratio of the motor 2'b and the motor 2'a is maintained at 1: 1 by the command of the computer,
The total amount of the sample supplied from the mixer 4 to the nebulizer 5 is constant, and the sample always contains a constant concentration (for example, 10 ppm) of the internal standard element. Therefore, the Ni content (that is, Ni concentration) in the measured liquid can be easily and accurately determined from the ratio SNi / SSc of the detection signal SNi of Ni and the detection signal SSc of scandium obtained from the measured liquid or standard solution. Become. Further, the standard addition method is carried out as follows in the examples of the present invention. That is, the solution to be measured is placed in the sample tank 1a and the solvent tank
Put 1 ppm Ni standard solution in 1b, for example. Then, according to a command from the computer 3, the rotation speed ratio of the motor 2'a and the motor 2'b is changed to, for example, (1000: 1) → (1000: 2) → (1000: 3) →
When changed to (1000: 4), mixer 4 to nebulizer 5
The concentration of Ni contained in the sample supplied to 1ppm → 2ppm → 3p
It will change from pm to 4 ppm. When it is not sufficient to control the rotation speed ratio of the motors 2'a and 2'b, the inner diameter of the tube through which the liquid to be measured flows and the above
Change the ratio of the inner diameter of the tube through which the Ni standard solution flows (for example,
100: 1). Therefore, Ni of known concentration is added to the solution to be measured such as 1 ppm, 2 ppm, 3 ppm and 4 ppm, and the Ni concentration in the solution to be measured is easily and accurately obtained by the standard addition method which is the extrapolation of the calibration curve. You will be asked.

<Effects of the Invention> According to the present invention as described above in detail, since the composition ratio of the solution can be easily changed by computer control, the multi-check calibration curve method, the standard addition method, and the internal standard method Both quantitative methods can be easily and accurately performed.

[Brief description of drawings]

The figure is a diagram for explaining the configuration of the embodiment of the present invention. 1a, 1b ... Tank, 2a, 2b ... Pump, 2'a, 2'b ... Motor, 3 ... Computer, 4 ... Mixer, 5 ... Nebulizer, 8 ... Plasma, 11 ... Nozzle , 12 …… Skimmer.

Claims (4)

[Claims] 1. A nebulizer atomizes a liquid containing a sample to form an aerosol sample, which is then introduced into a high-frequency inductively coupled plasma to excite the sample, and the resulting ions are introduced into a mass spectrometer through an interface to analyze an element to be measured. A first pump for sending a sample at a constant flow rate in an apparatus for analysis,
A second pump that sends the solvent at a constant flow rate, first and second motors that drive these pumps, a computer that controls the rotation of these motors, and the first and second pumps that deliver the solvent, respectively. A mixer that mixes the liquids and sends the mixed liquids to the nebulizer, and the computer changes variously the rotation speed ratio of the first and second motors according to the type of quantitative analysis method. High frequency inductively coupled plasma / mass spectrometer. 2. The method according to claim 1, wherein the quantitative analysis method is a multi-inspection calibration curve method in which quantitative analysis is performed using a calibration curve prepared using standard solutions having a plurality of concentrations. Analysis equipment. 3. The internal standard for determining the element to be measured in the solution to be measured from the ratio of the internal standard element to the element to be measured by adding an internal standard element of known concentration to both the solution to be measured and the standard solution. The analyzer according to claim (1) which is a method. 4. A standard for determining an element to be measured in a measured solution by extrapolating a calibration curve prepared by adding measured elements of known concentrations to a measured solution in a plurality of concentrations The analyzer according to claim (1), which is an addition method.