JPH0331745A - Atomic absorption spectrophotometer - Google Patents

Abstract

PURPOSE:To shorten the time for setting a spectroscope at the wavelength specific to a measuring element and to speed up the measurement by building the number of pulses for driving a dispersion element to the wavelength position of the measuring element to be measured by a pulse motor into a non-volatile memory. CONSTITUTION:The bright line spectral contg. the resonance rays from the measuring element are radiated from a light source 1. These spectra are introduced through an atomization section 2 to the spectroscope 3. The selection of the bright line in the spectroscope 3 is executed by rotating the dispersion element 10 by driving of the pulse motor 6 via a reduction gear 11. When the wavelength of a certain measuring element is assumed to be inputted from an operation section 9 to a CPU 7, the CPU 7 determines the number of pulses corresponding to the wavelength thereof from the non-volatile memory built therein and supplies the number of pulses to the pulse motor 6 to drive the dispersion element 10 of the spectroscope 3 so that the wavelength is immediately set at an optimum wavelength position. The number of pulses is promptly determined for the wavelength of the measuring element which is once subjected to peak searching in the past if the determined number of pulses is successively written into the non-volatile memory in such a manner. The wavelength setting is thus executed.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an atomic absorption spectrophotometer in which the dispersive element of the zero spectrometer is driven by a pulse motor. This invention relates to an atomic absorption spectrophotometer suitable for setting up.

[Conventional technology]

In a conventional atomic absorption spectrophotometer, for example.

The wavelength of the spectrometer is scanned in the vicinity of the set wavelength of the element to be measured in steps of o and oosnm, and the wavelength of the spectrometer is finally set at the peak position of the strongest light intensity (for example,
(See Publication No. 5040).

[Problem to be solved by the invention]

With conventional atomic absorption spectrophotometers, each time the element to be measured is changed, the spectrometer is set to the wavelength of the element to be measured using a peak search method, so it takes 1 to 2 minutes to set the wavelength each time.
Meanwhile, there was a point that the operator had to have. In particular, among the measurement conditions that must be set prior to performing one analysis, wavelength setting takes the longest time, accounting for approximately 90% of the total condition setting time, so measurements can be carried out quickly. The time required to set this wavelength was the biggest bottleneck in starting the process.

SUMMARY OF THE INVENTION An object of the present invention is to provide an atomic absorption spectrophotometer that can shorten the time required to set the spectrometer to a wavelength specific to the element to be measured and can quickly proceed with measurements.

[Means to solve the problem]

In order to achieve the above object, the atomic absorption spectrophotometer of the present invention adopts a method in which the dispersion element of the spectrometer is driven by a pulse motor, and the dispersion element is moved to the wavelength of the measurement element to be set and the corresponding wavelength position. It has a built-in nonvolatile memory that can maintain the relationship with the number of pulses for driving with a pulse motor.

When the dispersive element of a spectrometer is driven by a pulse motor, the relationship between the wavelength λ and the number of pulses P is P = K1s+n (K2λ) ---・
(]) However, +K1*Kz is a constant depending on the device, and the number of pulses P corresponding to the desired wavelength λ can be determined. Normally, taking into account mechanical processing errors, etc., the wavelength setting is performed by sending pulses little by little near the determined number of pulses P to find the exact wavelength position. There is no change.

There are approximately 70 wavelengths used in atomic absorption measurements.

If the number of pulses corresponding to this wavelength of about 70 m is stored in a table in a non-volatile memory, there is no need to perform a peak search each time. 1σ of the table held in non-volatile memory
(number of pulses corresponding to wavelength) is.

At first, put zeros in everything. When a wavelength setting for a certain element to be measured is requested, a peak search is performed only when the value in Table 2 is zero, and the number of pulses found in the water type is written in the table. In this way, the number of pulses determined is written in the table of the +1Ii quaternary non-volatile memory, and for the wavelength of the measured element for which a peak search was performed once in the past, the number of pulses is immediately determined and the wavelength can be set. can. Of course, if you perform a peak search for all 70 wavelengths in advance.

There is no need to perform a beak search for all wavelengths during measurement. Furthermore, if a wavelength shift occurs due to aging, it is advisable to add a function to update the values in the table in the nonvolatile memory as necessary.

[Effect]

In the atomic absorption spectrophotometer configured as described above, when the wavelength of the element to be measured is input from the operation unit, the number of pulses corresponding to the wavelength is stored in the non-volatile memory in the form of a table and the dispersion of the spectrometer is calculated. The wavelength is set at the optimum wavelength position immediately after driving the element with a pulse motor. If the number of pulses corresponding to the wavelength of the measurement element is not stored in the non-volatile memory, a peak search is performed in the same way as normal wavelength setting.

The wavelength is set by determining the exact wavelength t, and in preparation for the wavelength setting of the 11 constant elements from the 0th time, the number of pulses corresponding to the optimum wavelength position is held in a non-volatile memory.

In this way, the time required to set the wavelength each time the element to be measured is changed is reduced. Ql rays containing the resonance line of the element to be measured are emitted, and these are passed through the atomization section 2 by the optical system and introduced into the 1-minute beam P#3. Among these emission lines, there are 11! 'i
This includes light that is not received at all or light that has a low degree of absorption, and these are excluded by the spectrometer 3, and only the emission line (wavelength) with the highest absorption P8 is selected and converted into an electrical signal by the detector 4. converted.

Selection of bright lines in the spectrometer 3 is carried out by rotating the 9-dispersion element 10 by driving the pulse motor 6 via the deceleration i11 (see FIG. 2).

On the other hand, in the atomization section 2, the measurement element contained in the sample is atomized by thermal dissociation, and among the light passing through the interstitial section, the bright line (wavelength) with the highest absorption sensitivity is selectively and strongly absorbed.

The signal detected by the detector at4 is amplified by the amplifier 5.

The CPU 7 of the signal processing section performs logarithmic conversion, and displays t proportional to absorbance or the value converted to concentration on the display section 8.

The CPU 7 has a built-in nonvolatile memory.

This non-volatile memory stores approximately 70 different wavelengths and the pulse motor 6 moves the spectrometer 3 to the corresponding wavelength position. I element 10'
The relationship with the number of pulses for fe driving can be maintained in a table format.

Now, if the wavelength of a certain element to be measured is input from the operation unit 9, the CPU 7 calculates the number of pulses corresponding to that wavelength from the non-volatile memory, supplies the number of pulses to the pulse motor 6, and controls the dispersion of the spectrometer 3. Element 10 can be driven to set its optimum wavelength position. If non-volatile memory does not hold the number of pulses corresponding to that wavelength.

Determine the number of pulses using the above-mentioned formula (C+), and send pulses little by little around the determined number of pulses to reach the exact location @
The number of pulses corresponding to the exact wavelength position determined in this way is stored in non-volatile memory and
Next time when setting the wavelength of the same element to be measured, the number of pulses corresponding to the optimum wavelength position is immediately determined, and the wavelength can be set.

〔Effect of the invention〕

Since the present invention is configured as described above, the wavelength of the measurement element can be quickly set.

Since the time required to prepare measurement conditions prior to analysis can be shortened, the operator can efficiently carry out minute Vr.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing the atomic absorption spectrophotometer of the present invention,
FIG. 2 is a diagram showing the configuration of the spectrometer.

Claims (1)

[Claims] In an atomic absorption spectrophotometer in which a dispersive element of a spectrometer is driven by a pulse motor, a relationship between the wavelength of a measurement element to be set and the number of pulses for driving the dispersive element to the corresponding wavelength position by the pulse motor is maintained. An atomic absorption spectrophotometer characterized in that it is equipped with a non-volatile memory capable of storing data.