JPH0527816B2 - - Google Patents
Info
- Publication number
- JPH0527816B2 JPH0527816B2 JP11212884A JP11212884A JPH0527816B2 JP H0527816 B2 JPH0527816 B2 JP H0527816B2 JP 11212884 A JP11212884 A JP 11212884A JP 11212884 A JP11212884 A JP 11212884A JP H0527816 B2 JPH0527816 B2 JP H0527816B2
- Authority
- JP
- Japan
- Prior art keywords
- stage
- temperature
- energization
- sample
- schedule
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 21
- 229910002804 graphite Inorganic materials 0.000 claims description 21
- 239000010439 graphite Substances 0.000 claims description 21
- 238000000889 atomisation Methods 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 7
- 238000010521 absorption reaction Methods 0.000 claims description 5
- 238000005259 measurement Methods 0.000 claims description 4
- 239000000523 sample Substances 0.000 description 13
- 238000000034 method Methods 0.000 description 9
- 238000004380 ashing Methods 0.000 description 8
- 238000004458 analytical method Methods 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 238000001479 atomic absorption spectroscopy Methods 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000012488 sample solution Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/71—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light thermally excited
- G01N21/74—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light thermally excited using flameless atomising, e.g. graphite furnaces
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Geology (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Description
【発明の詳細な説明】
イ 産業上の利用分野
本発明はフレームレス原子吸光分析用試料原子
化炉の温度制御装置に関する。DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a temperature control device for a sample atomization reactor for flameless atomic absorption spectrometry.
ロ 従来技術
フレームレス原子吸光分析用試料原子化炉はグ
ラフアイトチユーブで、管軸方向に光を通し、チ
ユーブ内に滴下した試料溶液をチユーブ自体に通
電して加熱するようになつている。こゝで通電は
次のようなスケジユールで行われる。第１段では
小電流を流して試料を乾燥し、第２段では中電流
を流して試料を稍強熱灰化させ、最終段で大電流
を流して炉温を最高温まで上げ、その昇温の過程
で試料を原子化させる。B. Prior art A sample atomization reactor for flameless atomic absorption spectrometry is a graphite tube, in which light is passed in the tube axis direction, and the sample solution dropped into the tube is heated by passing electricity through the tube itself. Here, energization is performed according to the following schedule. In the first stage, a small current is applied to dry the sample, in the second stage, a medium current is applied to slightly ignite the sample, and in the final stage, a large current is applied to raise the furnace temperature to the maximum temperature. The sample is atomized during the heating process.
上述した通電スケジユールを実現するための従
来の定温度制御方式では、第２段の中電流を流す
灰化段階及び最終段の最高温度の段階（原子化段
階）では定温度制御がなされているが、灰化段階
から原子化段階に温度が昇温する中間過程は定温
度制御状態ではない。この中間過程の昇温速度は
グラフアイトチユーブに印加される最大電圧とグ
ラフアイトチユーブの電気抵抗によつて定まり、
電気抵抗はチユーブ毎にばらついているし、同一
チユーブでも何回も使用しているとチユーブ自体
が次第に消耗して来ることによつて変つてくる。
他方分析において必要な原子吸収のピークはこの
中間過程で発生するように最終段の原子化温度が
設定してあるので、グラフアイトチユーブの電気
抵抗値が分析結果に影響し、分析結果の再現性が
低下する。例えば昇温速度が遅い場合は現れる原
子吸収ピークの時間幅が広がるが、試料の気化が
遅いから原子蒸気の濃度が低く、ピーク高さは低
くなり、かつ蒸発に時間がかゝつているのでその
間に散逸してしまう量が増えて昇温速度が高い場
合よりピーク面積が小さくなる。 In the conventional constant temperature control method for realizing the above-mentioned energization schedule, constant temperature control is performed in the ashing stage in which a medium current is passed in the second stage and the highest temperature stage (atomization stage) in the final stage. , the intermediate process in which the temperature increases from the ashing stage to the atomization stage is not a constant temperature control state. The temperature increase rate during this intermediate process is determined by the maximum voltage applied to the graphite tube and the electrical resistance of the graphite tube.
Electrical resistance varies from tube to tube, and even if the same tube is used many times, it will change as the tube itself gradually wears out.
On the other hand, the atomization temperature of the final stage is set so that the atomic absorption peak necessary for analysis occurs during this intermediate process, so the electrical resistance value of the graphite tube affects the analysis results, and the reproducibility of the analysis results is affected. decreases. For example, when the heating rate is slow, the time width of the atomic absorption peak that appears increases; however, because the sample evaporates slowly, the concentration of atomic vapor is low, and the peak height is low. The amount of heat dissipated increases, and the peak area becomes smaller than when the heating rate is high.
ハ 目的
本発明はグラフアイトチユーブのばらつきや使
用による劣化に関係なく、灰化段階から原子化段
階に移る昇温過程の温度変化を一定にして測定の
再現性を向上させることを目的とする。C. Purpose The present invention aims to improve the reproducibility of measurements by keeping the temperature change constant during the heating process from the ashing stage to the atomization stage, regardless of variations in graphite tubes or deterioration due to use.
ニ 構成
段階的に増加する通電の第１段或は第２段（灰
化段階）等、最終段階を除く適宜の通電段階にお
ける通電時を利用してグラフアイトチユーブの電
気抵抗値を検出しておき、その値に応じて通電の
最終段階における上記中間過程（昇温過程）での
電流を制御して、この過程での温度変化率を毎回
同じにするようになつている。D. Configuration The electrical resistance value of the graphite tube is detected by using the energization time in an appropriate energization stage excluding the final stage, such as the first stage or second stage (ashing stage) of energization that increases in stages. The temperature change rate in this process is made the same each time by controlling the current in the intermediate process (heating process) at the final stage of energization according to the value.
ホ 実施例
第１図は本発明の一実施例を示す。GTが試料
原子化炉のグラフアイトチユーブで降圧トランス
Ｔの２次側に接続されている。グラフアイトチユ
ーブGTへの電力供給量はトライアツクTAの点
弧位相角の制御によつて調節される。DTはフオ
トダイオードであり、グラフアイトチユーブGT
からの熱輻射線を受けて信号を出す。その信号は
アンプSA1で増幅され、SA1の出力Vsがコント
ロールアンプCAに入力される。SA1の出力Vsと
グラフアイトチユーブGTの温度との関数関係は
予め調べておいて温度プログラマTPには第１段、
第２段等の温度データとして記憶させてある。温
度プログラマTPは予め設定されたスケジユール
に従い、夫々の段階における温度信号をコントロ
ールアンプCAに基準レベル信号Vrとして出力す
る。コントロールアンプCAは上記VsとVrとの差
の信号を増幅してパルスジエネレータPGに送り、
PGは入力信号に応じたタイミングでパルスを発
生しトライアツクTAの制御端子に印加して、
TAの点弧位相を制御し、グラフアイトチユーブ
GTが温度プログラマTPによつて指定された温
度になるように同チユーブへの供給電力が制御さ
れる。E. Embodiment FIG. 1 shows an embodiment of the present invention. GT is connected to the secondary side of the step-down transformer T by the graphite tube of the sample reactor. The amount of power supplied to the graphite tube GT is adjusted by controlling the firing phase angle of the triac TA. DT is photodiode, graphite tube GT
emit a signal by receiving thermal radiation from the The signal is amplified by amplifier SA1, and the output Vs of SA1 is input to control amplifier CA. The functional relationship between the output V s of SA1 and the temperature of the graphite tube GT has been investigated in advance, and the temperature programmer TP has the first stage,
It is stored as temperature data of the second stage, etc. The temperature programmer TP outputs the temperature signal at each stage to the control amplifier CA as a reference level signal V r according to a preset schedule. The control amplifier CA amplifies the signal of the difference between the above V s and V r and sends it to the pulse generator PG.
PG generates a pulse at a timing according to the input signal and applies it to the control terminal of triac TA,
Controls the firing phase of TA and graphite tube
The power supplied to the tube is controlled so that GT reaches the temperature specified by the temperature programmer TP.
第１図で鎖線で囲んだ部分が本発明に係る最大
電流設定回路である。トランスＴの１次側には電
流検出コイルCTが鎖交させてあり、同コイルの
出力はアンプSA2を介して関数発生器Ｆに入力
される。アンプSA2の出力はグラフアイトチユー
ブGTに供給する電流値に対応した信号で、通電
スケジユールの一つの段階例えば第２段階の灰化
段階において、グラフアイトチユーブが劣化して
おれば少くなる性質を有する。つまり、グラフア
イトチユーブは使用を繰返していると、次第に消
耗して肉厚が薄くなり抵抗が増大して来るから、
同じ温度を得るのに要する電流は少くてすむよう
になる。関数発生器Ｆは通電スケジユールの一
つの段階例えば第２段の灰化段階におけるアンプ
SA2の出力と次段階の試料原子化段階に移行する
中間過程での温度変化率を毎回同じにするための
最大電流値との関係関数を発生するもので、この
関数形は予め実験で決められている。Ｓ／Ｈはサ
ンプルホールド回路で、温度プログラマTPから
の信号で第２段階の終了直前の関数発生器Ｆの
出力をホールドする。SWは通常OFFで、温度プ
ログラマTPからの上記サンプルホールド信号に
応答してONされるスイツチである。そこで通電
スケジユールが最終段階に達すると上記スイツチ
がONとなり、パルスジエネレータPGの入力信
号は抵抗とダイオードとよりなるクランパーCL
によつてサンプルホールド回路Ｓ／Ｈの出力まで
引下げられ、トライアツクTAの点弧位相が進め
られて、グラフアイトチユーブにはその劣化程度
に応じた最大電流が供給されるようになり、所定
の昇温速度で昇温し、試料の原子化が行われる。
なお上例で関数発生手段が二つ使われているが、
これらは温度プログラマTPを兼ねたコンピユー
タが与えられた実験式に基いて演算する構成にな
つている。 The portion surrounded by a chain line in FIG. 1 is the maximum current setting circuit according to the present invention. A current detection coil CT is linked to the primary side of the transformer T, and the output of this coil is input to the function generator F via the amplifier SA2. The output of the amplifier SA2 is a signal corresponding to the current value supplied to the graphite tube GT, and has the property of decreasing if the graphite tube has deteriorated during one stage of the energization schedule, such as the second ashing stage. . In other words, if the graphite tube is used repeatedly, it will gradually wear out and become thinner, increasing the resistance.
Less current is required to obtain the same temperature. The function generator F is an amplifier in one stage of the energization schedule, for example the second ashing stage.
It generates a relationship function between the output of SA2 and the maximum current value to make the temperature change rate the same every time during the intermediate process of transitioning to the next sample atomization step, and the form of this function is determined in advance by experiment. ing. S/H is a sample and hold circuit that holds the output of the function generator F just before the end of the second stage using a signal from the temperature programmer TP. SW is a switch that is normally OFF and is turned ON in response to the above sample hold signal from the temperature programmer TP. Therefore, when the energization schedule reaches the final stage, the above switch turns ON, and the input signal of the pulse generator PG is transferred to the clamper CL, which is made up of a resistor and a diode.
The output of the sample and hold circuit S/H is lowered by The temperature is raised at a rapid rate, and the sample is atomized.
In addition, in the above example, two function generation means are used,
These are configured so that a computer that also serves as a temperature programmer TP performs calculations based on a given experimental formula.
第２図ａは通電スケジユールの一例の温度変化
の関係を示すグラフである。Ｔ１は通電の第１段
階乾燥段階の温度、Ｔ２は第２段の灰化段階の温
度、T3は最終の原子化段階の温度である。第２
図ｂは原子化段階の時間軸を伸ばして表わしたも
ので、鎖線は電流を示す。電流は灰化段階の終り
t3の時点で中電流から、上述した所によつて設定
される最大電流値まで一時に変化する。これに応
答してグラフアイトチユーブの温度はt3時点から
傾斜的に上昇し、t3′の時点で最大値に達する。
この昇温過程のt3〜t3′の時間幅内で原子吸光の
ピークが現れる。最大電流値Imを変えることで、
この昇温傾斜を図点線のように加減できる。上述
構成はこの昇温過程の傾斜が毎回同じになるよう
に作動しているのである。 FIG. 2a is a graph showing the relationship between temperature changes and an example of the energization schedule. T1 is the temperature of the first drying stage of energization, T2 is the temperature of the second ashing stage, and T3 is the temperature of the final atomization stage. Second
Figure b shows an extended time axis of the atomization stage, and the dashed line indicates the current. Current is at the end of the ashing stage
At time t3, the current changes at once from the medium current to the maximum current value set by the above-mentioned location. In response to this, the temperature of the graphite tube increases gradually from time t3 and reaches its maximum value at time t3'.
An atomic absorption peak appears within the time range from t3 to t3' during this temperature rising process. By changing the maximum current value Im,
This temperature increase slope can be adjusted as shown by the dotted line in the figure. The above-mentioned configuration operates so that the slope of this temperature increase process is the same every time.
ヘ 効果
本発明は上述したような構成で、第２図ｂによ
つて説明すれば、従来は原子化段階で単にＴ３が
一定になるように制御していただけなので、昇温
過程t3〜t3′間の昇温の傾斜角はグラフアイトチ
ユーブの抵抗の違いによつて異なり、同一チユー
ブでも使用する毎に劣化が進行するから毎回変化
し、測定の再現性に限界があつたのが、本発明に
よればt3〜t3′間の昇温傾斜が毎回同じになるの
で、測定の再現性が向上する。F. Effect The present invention has the above-mentioned configuration, and as explained with reference to FIG. The inclination angle of the temperature rise between the graphite tubes differs depending on the resistance of the graphite tube, and even the same tube deteriorates each time it is used, so it changes each time, which limits the reproducibility of measurement. According to , the temperature increase slope between t3 and t3' is the same every time, improving the reproducibility of measurements.
第１図は本発明の一実施例の回路図、第２図ａ
は温度化のグラフ、同図ｂはａにおける一部の時
間軸を拡大したグラフである。
GT……グラフアイトチユーブ、DT……温度
検出のためのホトダイオード、TP……温度プロ
グラマ、PG……パルスジエネレータ、CT……電
流検出コイル、Ｆ……関数発生器、Ｓ／Ｈ……
サンプルホールド回路。
Fig. 1 is a circuit diagram of an embodiment of the present invention, Fig. 2a
is a graph of temperature change, and b of the same figure is an enlarged graph of a part of the time axis in a. GT...Graphite tube, DT...Photodiode for temperature detection, TP...Temperature programmer, PG...Pulse generator, CT...Current detection coil, F...Function generator, S/H...
Sample and hold circuit.
Claims (1)
によつて試料原子化炉のグラフアイトチユーブへ
の通電電流を制御し、上記スケジユールの最終段
階の通電中の試料原子化炉の昇温過程で試料を原
子化させ測定を行う原子吸光分析装置において、 上記通電スケジユールの最終段階を除く適宜段
階において、定温制御を行う手段と、この通電段
階において上記グラフアイトチユーブに供給され
ている電流値を検出する手段と、その電流値に対
して予め設定された関数関係を持つように上記通
電スケジユールの最終段階におけるグラフアイト
チユーブへの供給電流を制御する手段を備え、 上記関数関係を、上記通電スケジユールの最終
段階における試料原子化炉の昇温過程が毎回同じ
になるように設定したことを特徴とする原子吸光
分析装置。[Claims] 1. The current applied to the graphite tube of the sample atomization reactor is controlled by an energization schedule in which the current value increases in stages, and the current applied to the sample atomization reactor is energized in the final stage of the schedule. In an atomic absorption spectrometer that performs measurement by atomizing a sample during the heating process, a means for constant temperature control is provided at appropriate stages other than the final stage of the energization schedule, and a means for supplying the graphite tube to the graphite tube during this energization stage. A means for detecting a current value, and a means for controlling the current supplied to the graph eye tube at the final stage of the energization schedule so as to have a preset functional relationship with respect to the current value, and the functional relationship is An atomic absorption spectrometer characterized in that the heating process of the sample nuclear reactor at the final stage of the energization schedule is set to be the same every time.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11212884A JPS60253851A (en) | 1984-05-30 | 1984-05-30 | Atomic absorption analyzer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11212884A JPS60253851A (en) | 1984-05-30 | 1984-05-30 | Atomic absorption analyzer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60253851A JPS60253851A (en) | 1985-12-14 |
| JPH0527816B2 true JPH0527816B2 (en) | 1993-04-22 |
Family
ID=14578896
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11212884A Granted JPS60253851A (en) | 1984-05-30 | 1984-05-30 | Atomic absorption analyzer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60253851A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04355347A (en) * | 1991-05-31 | 1992-12-09 | Shimadzu Corp | Atomic absorption spectrophotometer |
-
1984
- 1984-05-30 JP JP11212884A patent/JPS60253851A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60253851A (en) | 1985-12-14 |
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