JPS628133B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a burner used in atomic absorption spectrometry and the like.

A conventional burner for atomic absorption spectrometry has a structure as shown in FIG. Reference numeral 1 denotes a mixture vaporization chamber, with a burner nozzle 2 opening on the left side, and a double pipe inserted from the right end into the narrowed part 3 on the right side. Air or a combustion supporting gas such as nitrous oxide is supplied to the double outer tube 4. A fuel gas such as acetylene or hydrogen and an auxiliary combustion gas are supplied to the narrowed part 3 of the mixture vaporization chamber. The auxiliary combustion gas and the fuel gas are mixed in the chamber 1, ejected from the crater 2, and burned to form a flame F. The inner tube 5 of the double tube is extended and the other end is inserted into the container 6. The container 6 contains a solvent in which a sample is dissolved or a sample solution. When the auxiliary combustion gas is sent to the outer tube 4 of the double tube, when the auxiliary combustion gas is ejected from the outer tube 4, a low pressure area is formed around the left end opening of the inner tube 5, so the liquid in the melter 6 is sucked into the inner tube. It is ejected from the opening of 5 in the form of mist droplets. This liquid is mixed with a mixed gas of fuel and auxiliary gas in the mixing chamber and sent into the flame F.

The conventional burner described above has the following drawbacks.

(1) A large amount of sample solution is required. The sample is in container 6
In conventional burners, the sample solution is continuously supplied, and the sample solution is measured only after the atomic density of the target element in the flame becomes constant and the measurement signal reaches a steady state. minimum number
ml is required.

(2) A highly viscous sample such as serum cannot be atomized by the suction force of the auxiliary gas ejected from the outer tube 4, so it cannot be subjected to absorption analysis as it is.

(3) Samples that use nonflammable solvents such as chloroform or carbon tetrachloride for dissolution cannot be directly analyzed because the flame may go out or become unstable due to the large amount of sample supplied.

(4) After analyzing one sample, only the solvent is supplied to the inner tube 5 until the sample remaining and adhering to the inner tube 5 is removed (during which time the flame continues to burn).
It requires washing, and analysis cannot be performed by changing samples one after another, making analysis time-consuming when handling a large number of samples.

(5) In atomic absorption spectrometry, coexisting substances may affect the measured value of the element to be quantified in the sample. In such cases, adding a third substance (interference remover) to the sample can In some cases, the effects of coexisting substances can be removed. For example, when measuring Mg, if Al, Si, P, etc. coexist, they will cause negative interference (lowering the analysis value) to the Mg analysis value, but adding La, Sr, etc. as an interference remover will remove the above interference. can. However, with conventional burners, it is necessary to add an interference remover to each sample, which requires a sample pre-analysis treatment step, which becomes very troublesome when there are a large number of samples.

The present invention was made with the object of eliminating the above-mentioned drawbacks of conventional burners for atomic absorption spectrometry.

The present invention provides a burner for atomic absorption spectrometry analysis in which a carrier solution is continuously sprayed and supplied into the mixing chamber of the burner, and a fixed amount of sample is introduced into the carrier solution supply channel with a microsyringe or the like. It is something. The present invention will be explained below with reference to Examples.

FIG. 2 shows a burner according to an embodiment of the present invention. B is the burner body, and the inside thereof is a mixing chamber 1. 2 is the burner crater. The right end 3 of the mixing chamber is narrow and a double pipe W is inserted therein, and in the part 3 a narrow space is formed around the outer periphery of the double pipe W, into which the fuel gas supply pipe f opens. , hydrogen, acetylene, etc. are supplied, and a combustion auxiliary gas supply pipe (a) such as air, nitrous oxide, etc. is open. Double pipe W
consists of an outer tube 4 and an inner tube 5, and the left end opening of the outer tube 4 surrounds the left end opening of the inner tube 5. The inner tube 5 is extended and inserted into the container 6. Container 6 contains only carrier solution. A combustion auxiliary gas supply pipe a' opens into the outer pipe 4 of the double pipe W from the side. The inner tube 5 is bent laterally in the enlarged part 7 (rather, the carrier solution supply pipe 5' opens into the enlarged part 7 from the side), and the enlarged part 7 opens to the right and its opening is It is closed with a stopper 8 made of silicone rubber or the like. Reference numeral 9 denotes a microsyringe, which is inserted into the enlarged part 7 through the rubber stopper 8 with its injection needle, and the sample solution is injected into the enlarged part 7. Numeral 10 in the mixing chamber 1 is a glass bead for further dividing the jetted carrier solution droplet or sample solution droplet.
Note that a metering pump may be used as the sample injection means.

The operation of the above-mentioned burner will be explained. Fuel gas and combustion auxiliary gas are supplied from the fuel supply pipe f and combustion auxiliary gas supply pipes a and a'. These gases are mixed in the mixing chamber and ejected from the crater 2 to form a flame F. When the auxiliary gas is supplied from the auxiliary gas supply pipe a' and is ejected from the open end of the outer tube 4, a low-pressure area is formed around the opening of the inner tube 5, and the solvent in the container 6 is sucked into the inner tube 5. It is sprayed out from the open end in the form of a mist. Then, it collides with the glass beads 10 and is split into fine atomization, which is further mixed with fuel and auxiliary gas in the mixing chamber and ejected from the crater 2. In this way, the carrier gas is constantly supplied to the flame F. Here, if the sample dissolved in any solvent or the sample is originally a liquid (such as serum), it is directly injected into the enlarged part 7 of the inner tube 5 using the microsyringe 9. The injected sample is carried by the carrier solution flowing through the inner tube 5 and is immediately sprayed into the mixing chamber 1 from the open end of the inner tube 5, where it is mixed with the fuel gas, auxiliary gas, and carrier solution droplets. It is sent from the crater 2 into the flame F.

Figure 3 shows the recording results of absorbance signals when detecting Cu using this burner. The sample is
It was a chloroform solution containing 0.5, 1.0, 1.5, and 2.0 ppm of Cu, the amount of sample injection was 80μ, water was used as the carrier solution, acetylene was used as the fuel gas, and air was used as the auxiliary gas. Note that background absorption due to chloroform has been corrected.

In the case of the present invention, since the time during which the sample is introduced into the flame F is short, the absorbance signal of light at a specific wavelength due to the element to be detected and quantified becomes spike-like as shown in Fig. 3 when the amount of sample injected is small. If the sample injection amount is constant, the height or area of the signal is proportional to the concentration of the target element in the sample. Therefore, by measuring the height or area of the absorbance signal, the concentration of the target element in an unknown sample can be determined. This burner differs from conventional burners in that a fixed amount of sample is injected, and the injected sample is transported to the spray nozzle and atomized by a carrier solution that can be selected regardless of the dissolution of the sample, resulting in the following effects: .

(1) Only a small amount of sample is required. As can be seen from Figure 3, sufficient measurements can be made with a sample amount 1/20 of the conventional method.

(2) It is possible to selectively use a solution that is suitable for a trace amount of sample as a carrier and does not impair the stability of the flame, so even samples containing solvents such as carbon tetrachloride or chloroform, which extinguish or destabilize the flame, can be used as carriers. As shown in the figure, analysis can be performed with sufficient stability.

(3) For the same reason as above, highly viscous samples such as serum can be analyzed as is without dilution.

(4) The above-mentioned interference remover does not have to be added individually to a large number of samples, but can be added to the carrier solution, which greatly simplifies preparations for analysis.

(5) Since the solvent is constantly flowing without having to wash the burner for each sample, processing of a large number of samples can be carried out very efficiently.

(6) Since the carrier solution does not have to be able to dissolve the sample, materials can be chosen that will positively benefit the analysis. For example, organic solvents such as methyl isobutyl ketone are known to have a sensitizing effect on various elements. Conventional burners cannot be used if the sample does not dissolve in this type of solvent or is very difficult to dissolve. That is, since it was necessary for the solvent to be able to dissolve the sample, it was not possible to arbitrarily select a solvent to improve sensitivity as described above.

It should be noted that the burner according to the present invention can also be used for optical emission analysis and optical emission analysis using plasma, and it is clear from the above description that it is more effective than conventional burners.

[Brief explanation of the drawing]

FIG. 1 is a side view of a conventional example, FIG. 2 is a vertical sectional side view of an apparatus according to an embodiment of the present invention, and FIG. 3 is a graph showing measurement results when using the burner of the present invention. 1... Mixture vaporization chamber, 2... Crater, W... Double pipe, 4...
Outer tube, 5... Inner tube, 6... Container, 8... Silicone rubber stopper, 9... Micro syringe.

Claims (1)

[Claims] 1 A gas body is blown into the mixture vaporization chamber, and a carrier solution is suctioned and exposed through a suction pipe that opens into the gas supply flow path, and the carrier solution is atomized into a flame forming part communicating with the mixture vaporization chamber. An analytical sample atomization device having a configuration for supplying a mixed gas of a solution and the above-mentioned gaseous body, and comprising a sample injection section having a stopper into which a sample injection needle can be inserted in the middle of the above-mentioned suction tube. .