JP3084885B2 - ICP emission spectrometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ICP (High Frequency Inductively Coupled Plasma) emission spectrometer, and more particularly to a structure of a transport path of a sample aerosol from an ultrasonic nebulizer to a plasma torch.

[0002]

2. Description of the Related Art There is an ICP emission spectrometer that converts a liquid sample into an aerosol with an ultrasonic nebulizer and introduces the sample aerosol together with a carrier gas into a plasma torch. The ultrasonic nebulizer has an advantage that a sample aerosol having a small particle diameter can be generated and the amount of the sample aerosol can be adjusted irrespective of the supply amount of the carrier gas, as compared with the nebulizer of the spray type.

FIG. 2 shows a configuration of a main part of a conventional ICP emission spectrometer of this type. In the figure, reference numeral 1 denotes an ultrasonic nebulizer, and 2 denotes a plasma torch. The ultrasonic nebulizer 1 includes a nebulizer main body 3 and a desolvation unit 4. The nebulizer main body 3 is provided with an ultrasonic oscillator 6 in the atomization chamber 5, and the liquid sample S sent from the sample container 7 to the surface of the ultrasonic oscillator 6 by the pump 8 is used for the ultrasonic oscillator 6. Atomized by vibration. This nebulizer body 3
The aerosolized sample is sent to the desolvation section 4 together with the carrier gas flowing into the atomization chamber 5. The desolvation unit 4 reduces the size of the sample aerosol by heating and cooling, and removes a solvent (usually water) from the sample aerosol. The sample aerosol that has passed through the solvent removing section 4 is transported to the plasma torch 2 through the transport pipe 9.

[0004]

As described above, in a conventional ICP emission spectrometer having an ultrasonic nebulizer,
The ultrasonic nebulizer 1 is provided with a desolvation unit 4, and the solvent is removed from the sample aerosol by the desolvation unit 4, and the sample aerosol containing no solvent is sent to the plasma torch 2. In the case where the apparatus has been operated for a long time or the room temperature is low, the solvent contained in the sample 4 is completely removed as the solvent contained in the sample aerosol accumulates in the transport pipe 9 as droplets (usually water droplets). There are times when you can't. If the solvent accumulates as droplets in the transport pipe 9, the droplet-like solvent blows up to the plasma torch 2, and as a result, the plasma flame is extinguished.

[0005] In the conventional apparatus, the transport path between the ultrasonic nebulizer 1 and the plasma torch 2 is constituted by a pipe having substantially the same inner diameter so that the sample aerosol flows smoothly to the plasma torch 2. If the density of the sample aerosol fluctuates in step 3, the fluctuation of the density is sent directly to the plasma torch 2 in the form of a compressional wave, and the intensity of the light emission changes in the plasma torch 2. As a result, a stable photometric signal cannot be obtained,
There is a problem.

Furthermore, if the sample aerosol is not sufficiently finely divided in the desolvation section 4, the sample aerosol having a variation in particle size is introduced into the plasma torch 2 as it is, and the luminous intensity is increased. And a stable photometric signal cannot be obtained from this point.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to prevent the occurrence of a problem of extinction of plasmic flame due to a solvent droplet and to stabilize a photometric signal. .

[0008]

According to the present invention, in order to achieve the above object, a separation chamber having a drain port is interposed in a transport path of a sample aerosol between an ultrasonic nebulizer and a plasma torch. The separation chamber has an inner cylinder and an outer cylinder. The sample aerosol from the ultrasonic nebulizer is jetted into the inner cylinder, and the sample aerosol is transported from the outer cylinder to the plasma torch.

[0009]

According to the above arrangement, the sample aerosol sent from the ultrasonic nebulizer is ejected into the inner cylinder of the separation chamber just before the plasma torch, and flows in the opposite direction at the end of the chamber. Spills to the torch side. Meanwhile, the particle density of the sample aerosol is averaged, and droplets of the solvent and large particles of the sample aerosol are separated and removed.

[0010]

FIG. 1 is a configuration diagram showing a configuration of a main part of an ICP emission spectrometer according to an embodiment of the present invention.

As shown in FIG. 1, the ICP emission spectrometer of this embodiment includes an ultrasonic nebulizer 1 and a plasma torch 2, and the ultrasonic nebulizer 1 includes a nebulizer main body 3, a desolvation unit 4, Is the same as the above-mentioned conventional example. Further, the nebulizer main body 3 includes the atomization chamber 5 and
A liquid sample S that is provided from the sample container 7 to the surface of the ultrasonic vibrator 6 by the pump 8;
Atomization is performed by the vibration of the ultrasonic vibrator 6, and the desolvation unit 4 forms the sample aerosol from the nebulizer body 3 into fine particles by heating and cooling, and removes the solvent from the sample aerosol. Some points are the same as the conventional example.

The difference between the ICP emission spectrometer of this embodiment and the conventional example is that a transport pipe 9 for transporting a sample aerosol from the desolvation section 4 of the ultrasonic nebulizer 1 and a center pipe 2a of the plasma torch 1 are separated. Between the separation parts,
That is, the separation chamber 10 having the double cylinder structure is connected to each other. The separation chamber 10 includes an outer cylinder 11 having one end closed, a cap 12 for closing the other end of the outer cylinder 11,
It is composed of an outer cylinder 11 and an inner cylinder 13 mounted concentrically on the cap 12 side, and the cap 12 is supported in an inclined posture in which it is slightly higher. The cap 12 is provided with a nozzle 14 communicating with the transport pipe 9, and the nozzle 14 opens inside the inner cylinder 13 toward the inclined lower end. On the other hand, a drainage port 11a is provided at the inclined lower end of the outer cylinder 11, and an outlet 11b for the sample aerosol is provided at an upper part of the outer cylinder 11 at a halfway position in the longitudinal direction.
b is connected to the center tube 2a of the plasma torch 2. Reference numeral 15 denotes a drainage tank.

In the above configuration, the sample aerosol generated in the nebulizer main body 3 is reduced to fine particles and the solvent is removed in the desolvation section 4, and is sent out to the plasma torch 2 through the transfer pipe 9. Before the plasma torch 2, it flows into the separation chamber 10. In this separation chamber 10, the sample aerosol is jetted from the nozzle 14 into the inner cylinder 13, and is inverted at the inclined lower end of the outer cylinder 11 so as to be inverted.
And flows into the gap between the outer cylinder 11 and flows out from the outlet 11b to the plasma torch 2 side.

During this time, the sample aerosol is separated and separated according to the particle size by reversing the flow inside the separation chamber 10. That is, when the sample aerosol contains a droplet of the solvent, the droplet adheres to the wall surface of the outer cylinder 11 and collects at the lower end of the inclination along the wall surface. Then, the liquid is discharged to the outside from the liquid discharge port 11a.

Of the sample aerosols flowing into the separation chamber 10, those having a small particle size reach the outlet 11b, while those having a large particle size adhere to the wall surface of the outer cylinder 11,
Removed from sample aerosol. Therefore, by passing the sample aerosol through the separation chamber 10, the sample aerosol having a small particle size is selected, the sample aerosol having a fine particle size is supplied to the plasma torch 2, and the emission intensity does not vary.

Further, the sample aerosol temporarily stays and is stirred by reversing and flowing inside the separation chamber 10. Therefore, even if a sample aerosol having a variation in the density of particles is sent from the nebulizer main body 3,
In the separation chamber 10, the particle density is averaged, and in the plasma torch 2, the light emission intensity does not fluctuate due to the density of the particle density, and the light emission intensity is stabilized.

[0017]

According to the present invention, since the droplets of the solvent are separated and removed in the separation chamber, the droplets do not accumulate before the plasma torch, and the plasma flame is extinguished by blowing up the droplets. Is reliably prevented from occurring.

Further, even if the sample aerosol from the ultrasonic nebulizer has a variation in the density of the particles, the particle density of the sample aerosol is averaged in the separation chamber, so that the emission intensity of the plasma torch is also averaged. And a stable photometric signal can be obtained.

Moreover, the sample aerosol having a large particle diameter is separated and removed in the separation chamber, and the sample aerosol having a uniform particle diameter is supplied to the plasma torch.
Also from this point, the photometric signal is stabilized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of an ICP emission spectroscopy analyzer according to one embodiment of the present invention.

FIG. 2 is a configuration diagram of a main part of a conventional ICP emission spectrometer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ultrasonic nebulizer 2 Plasma torch 9 Conveyance pipe 10 Separation chamber 11 Outer cylinder 11a Drainage port 12 Inner cylinder 14 Nozzle

Continuation of the front page (56) References JP-A-3-1977849 (JP, A) JP-A-63-243872 (JP, A) JP-A-60-92157 (JP, U) JP-A-4-64754 (JP) , U) (58) Field surveyed (Int.Cl. ⁷ , DB name) G01N 21/62-21/74 G01N 1/28 JICST file (JOIS)

Claims (1)

(57) [Claims] 1. A separation chamber having a drain port is interposed in a transport path of a sample aerosol between an ultrasonic nebulizer and a plasma torch, and the separation chamber has an inner cylinder and an outer cylinder, An ICP emission spectrometer characterized in that a sample aerosol from an ultrasonic nebulizer is ejected into the inner cylinder and the sample aerosol is transported from the outer cylinder to a plasma torch.