PL153895B1 - Emission spectrometer with the indication in the microwaves plasma - Google Patents

Description

PATENT DESCRIPTION

153 895

OFFICE

PATENT

RP

Additional Patent to Patent No. - Pending: 86 10 10 (P. 261798)

Priority Application announced: 88 08 18

Patent description published: 1991 12 31

Int. Cl. ⁵ G01N 21/73 G01J 3/443 trnu

Creators of the invention: Andrzej P. Ramsza, Leszek G. Starski

The holder of the patent: "Unitra-Cemat", Institute of Electronic Materials Technology,

Warsaw Poland)

Emission spectrometer with excitation in inductive microwave plasma

The subject of the invention is emission spectrometer with excitation in inductive microwave plasma, applicable in elemental analysis of solutions.

Atoms of the analyzed sample are excited by the plasma of the working gas, created as a result of microwave resonance (AT Zander, GM Hieffje, Applied Spectroscopy 1981, 35, 357) and emit characteristic radiation, which is then analyzed by a classic photometric system with a monochromator or polychromator and any system detection.

The source of emission of the sample atoms is a specially designed plasma burner (A. Bollo Kamara, E. G. Codding, Spectrochim Acta 1981, 36B, 973; M. Beenakker, Spectrochim Acta 1976, 3IB, 483), placed in an inductive coupling resonator. The liquid sample is delivered to the stationary plasma zone in the form of a fine aerosol with the working gas. The aerosol is produced in a nebulizer.

In known emission spectrometers, the sample atoms are excited for emission by introducing them into a flame - in flame photometers, into a spark or an electric arc - in classic spectrometers or emission spectrographs, into the cathode of a fluorescent lamp - in spectrometers with a glow source, to high-frequency argon plasma coupled inductively - in ICP spectrometers and for argon or helium plasma, as well as molecular gases excited by a very high frequency field with capacitive coupling - in CMP spectrometers and inductive - in MIP spectrometers.

In the case of flame photometry, ICP spectrometry, CMP spectrometry, MIP spectrometry, less often in the case of arc excitation spectrometry, the sample can be introduced into the emission source as an aerosol liquid.

In the field of aerosol production, the use of cross-type pneumatic nebulizers (SE Valente, WB Schrenk, Appl. Spectrosc. 1970, 24, 197), coaxial (JE Meinhard, JCP. Infor. News-letter. 1976, 2, 163), Babington ( RS Babington, Popular Sci, 1973, May, 102), with a microporous structure element (LR Layman, FE Lichte, Anal. Chem.

153 895

1982, 54, 638) or ultrasonic. In either case, working gas is passed through the nebulizer to produce or transport the sample aerosol.

In known solutions of microwave inductive spectrometers, the source ΜΊΡ is connected to cross, coaxial, Babington pneumatic nebulizers or ultrasonic nebulizers.

Known solutions at low flow rates required by the MIP source have low detection limits for the individual elements. This is due to the low efficiency of the nebulizers used and the too large diameter of the liquid droplets in the aerosols obtained in them.

The essence of the spectrometer according to the invention is the combination of a very high frequency generator, a power transmission element and a resonator with a plasma torch - with a nebulizer with a microporous structure element.

The structure of the spectrometer according to the invention is explained in an exemplary embodiment, shown in the drawing in the form of a block diagram.

The spectrometer shown in the figure consists of a nebulizer 4 with a working gas source 5 and a liquid sample input, containing a zirconium ceramic plate with a microporous structure, connected by an aerosolized sample discharge tube to a plasma torch placed in the resonator 3. The resonator 3 is connected via a power transfer block 2 to a very high-frequency generator 1 and to a monochromatic or polychromator 6, which via detector 7 is connected to the recording block 8.

The method of operation of the spectrometer shown in the figure is to introduce a liquid sample with a peristaltic pump onto a zirconium ceramic plate. At the same time, a working gas is introduced into the plate, which causes the nebulizer 4 to disperse the solution into a fine aerosol. The aerosol together with the working gas stream is transferred to the plasma zone in the plasma torch located in the resonator 3. In the plasma zone the droplets evaporate, dissociate, atomize and excite. The excited atoms of the sample emit characteristic radiation. This radiation is directed to the monochromator 6 inlet, where it is split and then registered by the detector 7 and the recording block 8. The frequency of the radiation determines the type of the element, and the intensity - its concentration in the sample.

The spectrometer according to the invention enables operation with low gas and liquid flows. A nebulizer with a microporous structure element generates an aerosol with a very small droplet diameter (well below 1 μιη) with efficiencies of up to 95%. The spectrometer according to the invention allowed to achieve the limits of quantification and detection, similar to the limits obtained when introducing the sample to the plasma in the form of a gas.

Claims (1)

Patent claim Emission spectrometer with excitation in inductive microwave plasma, the system of which consists of a very high-frequency generator, connected through a power transmission element with a resonator, in which a plasma torch is placed, connected with a nebulizer with a working gas input and a liquid sample input, mono- or polychromator, detector and a recording system characterized in that, simultaneously with the ultrahigh frequency generator (1), the power transmission element (2) and the plasma torch resonator (3), it comprises a nebulizer (4) with a microporous structure element.