JP3756649B2 - High-speed counter-current chromatograph - Google Patents

High-speed counter-current chromatograph Download PDF

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JP3756649B2
JP3756649B2 JP34954197A JP34954197A JP3756649B2 JP 3756649 B2 JP3756649 B2 JP 3756649B2 JP 34954197 A JP34954197 A JP 34954197A JP 34954197 A JP34954197 A JP 34954197A JP 3756649 B2 JP3756649 B2 JP 3756649B2
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JPH11183455A (en
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英一 北爪
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英一 北爪
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【0001】
【発明の属する技術分野】
本発明は微量元素の分離、濃縮に関し、特に原子吸光分析法やICP発光分光分析法などにより溶液中の微量元素を分析するにあたって、感度を上げるための濃縮法及び高速向流クロマトグラフに係る。
【0002】
【従来の技術】
従来、原子吸光分析法やICP発光分光分析法などの機器分析法で溶液試料中の微量金属元素等を分析する際、予め試料を濃縮して感度を上げるための濃縮前処理法としてはイオン交換法や溶媒抽出法などの手法が一般的であった。しかしイオン交換法ではピークのブロードニングや樹脂の寿命などの問題がある。また溶媒抽出法では抽出の体積比をあまり大きく出来ず、微量の液体中に抽出するのが難しいなどの問題があった。これらの方法で最終的に分析に供せられる水溶液試料を0.5ml以下とするのは一般に難しい。0.1mlあるいはそれ以下の、できるだけ微小な体積中に物質を高倍率で濃縮できれば効率的な分析が可能になる。
【0003】
高速向流クロマトグラフを用いるpHゾーンリファイニング(pH−zone refining)法によれば、微小な体積まで濃縮が可能であるが、0.1ml以下に濃縮するためには出来るだけ細い(例えば直径0.5mm以下)チューブを使って、通常の装置で供せられる回転数以上の強い遠心力を与える必要がある。
【0004】
【発明が解決しようとする課題】
本発明の目的は、機器分析法等で高感度化を達成するため、微量元素のpH−ゾーンリファイニング法による濃縮法のための装置であって、分析用高速向流クロマトグラフとして使用できる装置を提供することにある。
【0005】
【課題を解決するための手段】
本発明は、回転可能な支持体;該支持体に自転及び公転可能に取付けられ、且つ周囲に液体搬送及び濃縮用のチューブを巻いた、自転及び公転駆動されるドラム;前記チューブと連結させる液体搬送用のチューブ;該支持体に取付けられ、前記液体搬送用のチューブを軸内の通路に通した前記ドラムの公転軸;及び自転軸と公転軸を結合する回転同期機構;を有する高速向流クロマトグラフにおいて、公転軸受けと自転軸受けを回転ドラムの片側に配置してなることを特徴とする高速向流クロマトグラフである。
【0006】
【発明の実施の形態】
本発明の好ましい実施の形態として以下のものがあげられる。
液体搬送用のチューブが、公転軸内を通って自転軸内へ連結される2本以上のチューブからなり、かつ互いに半回転以上捻じられたものである、クロマトグラフ。
ドラムの自転軸方向の厚みが100mm以下であり、公転半径が10cm以上で公転軸受けの回転数が1,000 rpmを超えるものである、クロマトグラフ。
公転軸を取り付けた支持体に、振動ピックアップを設け、かつ公転軸を挟んで自転軸の反対側に重りを取付けてなる、クロマトグラフ。
重りの取付け位置を自転及び回転軸方向に2個所以上配置してなる、クロマトグラフ。
公転軸内を通して外部に引き出した液体搬送用のチューブに、液体の流路切り換えバルブ、液体搬送用ポンプ、及び試料とチューブ内に固定される固定相とを流路内に導入するためのインジェクターを取付けてなる、クロマトグラフ。
公転軸内を通して外部に引き出した液体搬送用のチューブの出口側に分析装置を接続してなり、濃縮目的元素の分析を連続的に行い、チューブ内の濃縮状態を監視し、かつ測定の開始時間、バルブの開閉タイミング又はポンプの流速を自動的に制御し得る、クロマトグラフ。
【0007】
従来、高速向流クロマトグラフまたはコイルプラネット遠心器と呼ばれる装置は中心軸の両側に受け手がある、いわゆる両軸受け方式であった。本発明においては、この中心軸を片軸受とし、中心固定軸内より取り出される液体搬送用のチューブを中心固定軸の先端より取り出す事を可能にすることにより回転時に中心軸との接触部分を少なくしてチューブの耐久性を向上させた。さらに本発明によれば、カラムの取り扱いが容易になると共に、チューブの曲率半径を大きくできるので、チューブは高速回転に耐えることができる。それと同時に小型化できるので、公転半径(公転軸から自転軸までの距離)が10cm以上の場合、回転数が1,000rpm が限界であった従来装置より格段に高速回転が可能になった。
【0008】
本発明による高速向流クロマトグラフの概略の構造を図1に示す。
図1において、固定中心軸(公転軸)aに固定ギヤe−1が取り付けられている。回転ドラムdが連結されている回転軸cに固定されているギヤe−2は固定ギヤe−1と噛み合っている。e−1とe−2の歯数は同数とする。モータなどの動力を用いて固定中心軸aの回りでドラムを含む回転部分を回転させれば、ドラムdは自転しつつ固定軸aの回りを自転の角速度の1/2倍の角速度で公転する。つまり1回の公転につき2回の自転を行う。液体の入り口及び出口となる、少なくとも2本以上の液体搬送用のチューブbは固定軸aの一方(図では下部)より入り、固定軸の中を経由して図の上部先端より取り出され、お互いに捻じられながら回転軸(自転軸)cの末端より軸の中心に入り、内部を経由してドラムdに巻き付けられる。fは回転のバランスを取るための重り(カウンターバランス)であり、回転ドラムの重量に応じて調整し、静的及び動的バランスを調節する。
【0009】
pH- ゾーンリファイニング法は移動相と固定相にあらかじめ酸またはアルカリを溶かして両者の液性を逆にしておき、移動相を流して中和反応を行いながら、pHの境界に物質が集まることを利用して分離や濃縮を行う方法であり、既にItoらにより特許が出願されている。(米国特許第5,332,504及び5,354,473号明細書など)
【0010】
またモノグラフ("High-speed Countercurrent Chromatography", edited by Y. Ito and W.D. Conway, John Wiley & Sons, Inc., 1995)なども出版され、解説されている。カラムの中で中和反応が行われる結果、溶離液のpHはちょうど中和滴定の場合に見られるようなpH変化を示す。有機酸などの混合物試料の場合、試料のpKa及び分配比に従って順番に溶出させることができる。また、これまで難しかった高速向流クロマトグラフィーでのgオーダーの試料の分離が可能である。
【0011】
一方、カラムの中でpHが急激に変化する部分が移動して行くので、そのpHの境界に特定の化合物を封じ込め、数十倍以上の大きな濃縮率で濃縮できる利点がある。この場合、通常のクロマトグラフィーに見られるような、試料の拡散が無く、極めて微小な体積中に化合物が濃縮できる。そこで従来の溶媒抽出法に代わって微量金属不純物などの効率的な濃縮法として使用できるが、金属の濃縮を行なった例は無い。金属を濃縮する場合は固定相に錯体生成試薬(リガンド)を含有させれば良い。本発明により微量の金属が濃縮される様子を図2と図3に示す。
【0012】
図2は実験直後の様子で、初めに装置を回転させ、塩酸や硝酸などの酸を移動相とし、最初に試料をカラムに導入し始めた時に、試料中の金属イオンあるいは無機イオンがカラムの先端部分に濃縮される様子を示している。III の長方形で示されたゾーンが固定相であり、主成分はエーテルやヘプタンなどの有機溶媒であり、リガンドとしてDEHPA(ジ−2エチルヘキシルリン酸)などの錯体生成試薬、pH調整用としてアンモニア等のアルカリを含んでいる。IIの部分は試料であり、試料中に含まれる金属イオンが固定相中に十分抽出されるように、あらかじめアンモニア等でpHが調整されている。また金属イオンの水酸化物による沈殿が問題となる場合は、試料には沈殿を防ぐために酒石酸やクエン酸などの錯形成剤をあらかじめ加えておく。装置を回転させるとIII の固定相の部分(有機相)は移動相(酸溶液、図中MPと示されているIの部分)に比べて軽いので、数百rpm以上の回転を与えた場合、アルキメデスのスクリュー効果によりカラムのヘッド(入口側、図2では左側)に移動する。この移動しようとする力はカラムの回転数が大きくなるほど強いので、適当な条件のもとでは移動相をポンプで流してやっても押し出されることなく、固定相がカラム中に保持される。固定相の保持率はこの場合カラム全体に対する固定相の割合として0〜70%程度にわたって変化するが、移動相の流速や二相の組み合わせ、カラム回転数などの諸条件を一定にすればいつもほぼ一定の値が得られる。すなわちIII の長方形の部分は大きく移動することはなく、いつもカラム中のほぼ一定の位置に存在している。そこで初期の段階では目的のイオンはIII の左端の、濃く示したカラムヘッドに集まる。図では簡単のために水素イオンは省略しているが、M+ (金属イオンまたは無機イオン)がR- (錯形成試薬のイオン)と反応あるいは会合して固定相中に抽出される様子をあらわしている。
【0013】
図3はカラム中に試料が全部導入された後、濃縮された金属イオンや無機イオンが、pHの境界をはさんで抽出、逆抽出を繰り返しながらさらに濃縮されつつ進んで行く様子を示している。図3ではIIとIII を合わせた長方形のゾーンが固定相をあらわしている。
一方、酸を含む移動相(MP)は固定相と接触しながら常に一定の速度でカラムのヘッドからテール(終端、右方向)へと流れている。図中の大きな3つの矢印(HIGH)は移動相の流れを示している。移動相は酸性なので、固定相中のアンモニア等のアルカリを中和しつつカラム中を進んでいく。固定相のうち、IIで示される台形状の部分では有機相がすでに酸で中和されている。固定相のうち、右側のIII の部分は有機相はまだ酸との反応が終了しておらず、アルカリを含んでいる。色の濃くなっているIIとIII の境目の部分は酸とアルカリがちょうど中和されている領域(pHの境界)を示している。カラム内では十分な攪拌がなされているので、移動相中でも図中の点線で示したpHの境界が存在すると考えられる。
【0014】
pHの境界は移動相と同じ方向に進んでいくが、移動相中の酸と固定相中のアルカリが反応しつつ進むので、移動相の速度に比べて遅くなる。固定相中の小さい矢印(LOW)でpHの境界の移動方向を示している。そこで最初カラムヘッドに濃縮されたイオンM+ は、図中の矢印のサークルで示されるように、pHの境界を中心として、抽出と逆抽出を繰り返しながら移動相の速度よりゆっくりと固定相中を進んでいく。酸で中和された後の部分(II)ではイオンM+ は移動相に逆抽出される(図では水素イオンは省略している)。移動相の速度はpHの境界の移動速度に比べて早いので、逆抽出されたイオンはpHの境界を通過する。通過すると急激にpHが上がるので、リガンドイオンR- と再び結合し、固定相中に抽出される。このサイクルを何回も繰り返しながらイオンはカラムの終端に向かって進んでいく。そこで通常のイオン交換法やHPLC法と違ってカラム内でのイオンの拡散が無いので微量のイオンを極めて狭い領域に濃縮することができ、濃縮率を高めることができる。
【0015】
固定相中や試料中にアルカリが含まれていない場合は、イオンは固定相と移動相に対する分配比の差により分離しながらカラム中を進むが、この場合は通常のクロマト分離となり、pHの境界が存在しないので濃縮されることはない。分離の例については既に論文(E. Kitazume, N. Sato, Y. Saito and Y.Ito, Anal.Chem., 65,2255(1993).
E. Kitazume, M.Bhatnagar and Y. Ito, Mutual. separation of rare earth elements by high-speed countercurrent chromatography, Proc.Internat. Trace Anal. Symposium, 103,1990 (in Sendai, Japan).
E. Kitazume, M. Bhatnagar and Y. Ito, J.Chromatogr., 538,133(1991). やモノグラフ(E.Kitazume: Separation of Rare Earth and Certain Inorganic Elements by High-Speed Countercurrent Chromatography (Edited by Y. Ito and W.D. Conway)High-Speed Countercurrent Chromatography (John Wiley & Sons,Inc.), 415-443(1995)), また特許(Separation of rare earth elements and other compounds with high-speed countercurrent chromatography U.S. Pat. No.5,215,664(1993))などに示されている。
【0016】
なお、図2および図3では簡便のために水素イオンを省略したが、水素イオンと抽出試薬(DEHPA)を考慮した場合の抽出の様子を図4に示した。金属イオンはここではランタナイドなどの3価の陽イオンを例にとっている。太線はカラムの壁面を示している。カラム内の上の部分(固定相)にはDEHPAが含まれる。HGと略されているDEHPAはダイマーとなって3価の陽イオンと反応することが知られている。図中、液性が酸性になると平衡が左にずれ、金属イオンは移動相(水相)側に移る。一方液性がアルカリ性になると、平衡が右にずれ、金属イオンは固定相(有機相)側に移る。
【0017】
図5にポンプ、インジェクター、高速向流クロマトグラフ、検出器などを含んだシステムを示す。図中、1−l2は以下のとおりである。
1:エチルアルコール、2:イオン交換水、3:溶離液(塩酸等)、4−1,4−2,4−3:流路切り換えバルブ、5:ポンプ、6:インジェクター(試料)、7:インジェクター(固定相)、8:高速向流クロマトグラフ、9:検出器、10:出口(フラクションコレクター等に接続または廃棄)、11:インジェクター(標準試料)、l2:イオン交換水
図5において、はじめに流路切り換えバルブ(4−1)をエチルアルコール(1)、ついで水(2)に切り換えてポンプ(5)により適当な流速で流し、流路切り換えバルブ(4−2)を経由して出口(10)から排出して流路及び高速向流クロマトグラフ(8)のカラムを洗浄する。その後、流路切り換えバルブ(4−1)を溶離液(3)に切り換え、同時に流路切り換えバルブ(4−2)を排出側にしてポンプ内を溶離液で置換する。
ポンプを停止し、インジェクター(6)のループ中に、固定相に目的物が十分抽出されるようにpHを調整した試料、インジェクター(7)のループに固定相を導入する。インジェクター(7)、(6)を切り換えて溶離液の流路を両方導入側にする。
【0018】
高速向流クロマトグラフ(8)を1000rpm を超える一定回転数で動作させ、回転が安定したらポンプ(5)により溶離液の送液を開始する。
出口をフラクションコレクターに接続し、濃縮されたフラクションを得る。または検出器(9)によりピークをモニターし、濃縮されたフラクションのみ分取する。あるいは検出器の信号により直接定量値を得る。検出器(9)については、通常の液体クロマトグラフィー(HPLC)の場合に見られるような吸光光度計や光散乱計、屈折計などを使用する。または原子吸光分析装置やICP発光分光分析装置、ICP−質量分析装置等を使用する。
なお、検出器に導入する最適な流速を調整するため、流路切り換えバルブ(4−3)の開閉によりイオン交換水(12)を流路に加えることができるようになっている。イオン交換水を導入する場合は、検出器自体が流速を制御するポンプ等を持たない時は流路切り換えバルブ(4−3)と検出器(9)の間にポンプを入れる。
【0019】
【実施例】
以下、実施例をあげて説明する。
実施例 1
図6にZn、Mg、Ca各2ppbを含む0.1M酒石酸溶液10mlを試料とし、本システムで濃縮した結果を示す。なお、試料はアンモニア水でpHを7.1に調整した。ドラム(径100mm、厚さ50mm)に内径0.5mm、外形1.5mmのテフロンチューブを一層巻き付けて濃縮用カラムとした。(カラム長さは約10m、内容積は約2ml、公転半径10cm)高速向流クロマトグラフの装置の回転数は1200rpmとした。溶離液は酒石酸0.1Mを含む0.1M塩酸溶液、固定相は0.2MのDEHPAおよび0.18Mのアンモニアを含むヘプタン溶液0.6mlを用いた。図6において、横軸は0.1M塩酸溶離液の体積、縦軸は検出器(DCP発光分光分析装置)からの発光強度を示している。ポンプ流速は試料濃縮時は0.1ml/min 、発光強度測定時は1ml/min とした。溶離液の体積13.8mlより14mlにかけてPの強度が急激に低下しているが、これはpHの急峻な変化がこの領域で起こっていることを示している。14ml付近でMgとCaのピークが見られるので、これらの元素はpHの境界で濃縮されていることが分かる。一方、Znは少し遅れて14.3〜14.4ml付近でピークが見られる。これはZnの場合は他元素に比べてpHが減少しても有機相に抽出される割合(分配比)が大きいので溶出が遅れるためである。この例は分配比が異なっていれば通常のクロマトグラフィーのように分離も可能であることを示している。それに加えて通常のクロマトグラフィーでは不可能な濃縮が可能であることを示している。
【0020】
実施例 2
図7にCd、Mn、Ni、Cuなどの重金属を含む0.1M酒石酸標準溶液を濃縮した時の発光強度を示す。なお、実験条件は実施例1と同じである。Cd、Mn、Ni、Cu各2ppbを含む溶液10mlを試料とし、本システムで濃縮した。図7においてはPの発光強度が急激に減少する溶離液体積14mlのところで4元素ともピークが出現している。
【0021】
実施例 3
図8には水道水に酒石酸を加えて酒石酸0.1M溶液とし、アンモニア水でpHを8.0に調整した試料10mlを濃縮した結果を示す。実験条件は実施例1と同じである。図8にはZn、Mn、Caについての発光強度が示されている。Ca、ZnはMnに比べて大量に含まれていることがわかる。
【0022】
実施例 4
図9に水道水中のCd、Mn、Ni、Cuの濃縮結果を示す。実験条件は実施例1と同じである。また実施例3における水道水試料と同じものを使用している。Mn、Ni、Cuとも十分な発光強度が得られている。Cdの発光強度プロファイルを詳細に調べるため、図9の縦軸を拡大したものを図10に示す。Cdは通常水道水中にはppbレベルあるいはそれ以下と考えられるがはっきりしたピークが確認された。
【0023】
表1に実施例1より実施例4までの各元素の濃縮結果に基づき、標準試料のピーク面積を基準として、水道水中に極微量含まれるCd、Mn、Ni、Cuを定量した例を示す。
【0024】
【表1】

Figure 0003756649
【0025】
実施例 5
図11に水道水試料中のMn、Niの濃縮結果を示す。試料は実施例3の場合と同様の処理を行なっている。実験条件はポンプ流速が実験全部を通して0.1ml/min である以外は実施例1と同じである。またこの場合は検出器(DCP発光分光分析装置)に入る流量は図5の(12)よりイオン交換水を導入して約1ml/min になるように調整した。高速向流クロマトグラフの溶離液は0.1ml/min であり、ゆっくり検出器に導入されるので、より正確な発光プロファイルが示されている。発光強度のピーク幅はこの図で、約0.1mlとなっている。またカラム内の固定相の終端から検出器までのデッドスペースが約2mlあるので、濃縮後、検出器に到達するまでに試料ゾーンの拡散がある。それにもかかわらず、溶離液約0.1mlの範囲でピークが出終わっていることから、確実に0.1ml以内に濃縮されるていることがわかる。もともとの試料の体積は10mlであるので、体積比で100倍以上の濃縮率が達成されていることがわかる。
【0026】
【発明の効果】
本発明の高速向流クロマトグラフによれば、公転半径10cm以上で1,000rpm を超える高速回転が可能であり、Ca、Cd、Mg、Mn、Ni、Zn、Cu、Pbなどの金属を100μl以下の微小体積中に100倍以上の濃縮率で濃縮でき、超微量分析が可能となる。また、チューブの耐久性が大きく、カラムの取扱いも容易である。
【図面の簡単な説明】
【図1】本発明の高速向流クロマトグラフの概略の構造を示す説明図である。
【図2】高速向流クロマトグラフのカラムにおける、濃縮開始直後の、試料中の金属イオンがカラムヘッドに集まる様子を示す説明図である。
【図3】高速向流クロマトグラフのカラムにおける、pH界面での金属の濃縮の様子を示す説明図である。
【図4】高速向流クロマトグラフのカラムにおける、イオンの抽出および逆抽出を示す説明図である。
【図5】高速向流クロマトグラフを含む装置の概略の構成を示す説明図である。
【図6】高速向流クロマトグラフによるCa、Mg及びZnの標準溶液の濃縮結果を示すクロマトグラムである。
【図7】高速向流クロマトグラフによるCa、Mg、Ni及びCuの重金属標準溶液の濃縮結果を示すクロマトグラムである。
【図8】高速向流クロマトグラフによる、水道水試料中のZn、Mn及びCaの濃縮結果を示すクロマトグラムである。
【図9】高速向流クロマトグラフによる、水道水試料中のCd、Mn、Ni及びCuの濃縮結果を示すクロマトグラムである。
【図10】高速向流クロマトグラフによる、水道水試料中のCd及びNiの濃縮結果を示すクロマトグラムである。
【図11】高速向流クロマトグラフによる、水道水試料中のMn及びNiの濃縮結果を示すクロマトグラムである。
【符号の説明】
a 公転軸
b 液体搬送用のチューブ
c 自転軸
d ドラム
e−1 ギヤ
e−2 ギヤ
f 重り[0001]
BACKGROUND OF THE INVENTION
The present invention relates to separation and concentration of trace elements, and more particularly to a concentration method and high-speed counter-current chromatograph for increasing sensitivity when analyzing trace elements in a solution by atomic absorption spectrometry or ICP emission spectrometry.
[0002]
[Prior art]
Conventionally, when analyzing trace metal elements in solution samples by instrumental analysis methods such as atomic absorption spectrometry and ICP emission spectrometry, ion exchange is a pre-concentration method that concentrates the sample in advance to increase sensitivity. Methods such as the method and the solvent extraction method were common. However, the ion exchange method has problems such as peak broadening and resin life. Further, the solvent extraction method has a problem that the volume ratio of extraction cannot be increased so much that it is difficult to extract into a small amount of liquid. It is generally difficult to make an aqueous solution sample finally subjected to analysis by these methods to 0.5 ml or less. If the substance can be concentrated at a high magnification in the smallest possible volume of 0.1 ml or less, efficient analysis becomes possible.
[0003]
According to the pH-zone refining method using a high-speed counter-current chromatograph, it is possible to concentrate to a minute volume, but it is as thin as possible (for example, a diameter of 0) to concentrate to 0.1 ml or less. (5mm or less) It is necessary to give a strong centrifugal force exceeding the rotation speed provided by a normal device using a tube.
[0004]
[Problems to be solved by the invention]
An object of the present invention is an apparatus for concentrating trace elements by the pH-zone refining method in order to achieve high sensitivity in instrumental analysis and the like, and can be used as a high-speed counter-current chromatograph for analysis Is to provide.
[0005]
[Means for Solving the Problems]
The present invention relates to a rotatable support; a drum which is rotatably and reciprocally attached to the support and has a tube for transporting and concentrating liquid around it; a drum which is driven to rotate and revolve; a liquid which is connected to the tube A high-speed countercurrent flow comprising: a conveying tube; a revolving shaft of the drum attached to the support and passing the liquid-conveying tube through a passage in the shaft; and a rotation synchronization mechanism that couples the rotating shaft and the revolving shaft. The chromatograph is a high-speed countercurrent chromatograph characterized in that a revolution bearing and a rotation bearing are arranged on one side of a rotating drum.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention include the following.
A chromatograph in which a tube for transporting liquid is composed of two or more tubes connected to a rotation shaft through a revolution shaft, and twisted at least half a turn.
A chromatograph in which the thickness of the drum in the direction of the rotation axis is 100 mm or less, the revolution radius is 10 cm or more, and the revolution of the revolution bearing exceeds 1,000 rpm.
A chromatograph, in which a vibration pickup is provided on a support body to which a revolution shaft is attached, and a weight is attached to the opposite side of the revolution shaft across the revolution shaft.
A chromatograph in which two or more weight mounting positions are arranged in the direction of rotation and rotation axis.
A liquid flow path switching valve, a liquid transport pump, and an injector for introducing a sample and a stationary phase fixed in the tube into the flow path are provided in the liquid transport tube drawn outside through the revolution shaft. A chromatograph attached.
The analyzer is connected to the outlet side of the tube for transporting liquid drawn out through the revolution shaft, continuously analyzing the target element for concentration, monitoring the concentration state in the tube, and starting time of measurement. A chromatograph that can automatically control valve opening and closing timing or pump flow rate.
[0007]
Conventionally, an apparatus called a high-speed counter-current chromatograph or a coil planet centrifuge has been a so-called double-bearing system in which there are receivers on both sides of the central axis. In the present invention, the central shaft is a single bearing, and the tube for liquid conveyance taken out from the central fixed shaft can be taken out from the tip of the central fixed shaft, thereby reducing the contact portion with the central shaft during rotation. And improved the durability of the tube. Furthermore, according to the present invention, the column can be easily handled and the radius of curvature of the tube can be increased, so that the tube can withstand high-speed rotation. At the same time, since the size can be reduced, when the revolution radius (distance from the revolution axis to the revolution axis) is 10 cm or more, the rotation speed is significantly higher than that of the conventional apparatus whose limit is 1,000 rpm.
[0008]
A schematic structure of a high-speed countercurrent chromatograph according to the present invention is shown in FIG.
In FIG. 1, a fixed gear e-1 is attached to a fixed center axis (revolution axis) a. A gear e-2 fixed to a rotary shaft c to which the rotary drum d is connected meshes with the fixed gear e-1. e-1 and e-2 have the same number of teeth. If the rotating part including the drum is rotated around the fixed central axis a using the power of a motor or the like, the drum d revolves around the fixed axis a at an angular velocity that is 1/2 the angular velocity of the rotation while rotating. . In other words, two revolutions are performed per revolution. At least two or more liquid transfer tubes b that serve as an inlet and an outlet for liquid enter from one side (lower part in the figure) of the fixed shaft a, and are taken out from the upper end of the figure through the fixed shaft. The shaft enters the center of the shaft from the end of the rotating shaft (spinning shaft) c while being twisted by, and is wound around the drum d via the inside. f is a weight (counter balance) for balancing rotation, and is adjusted according to the weight of the rotating drum to adjust the static and dynamic balance.
[0009]
In the pH-zone refining method, acid or alkali is dissolved in the mobile phase and stationary phase in advance to reverse the liquidity of the two, and the mobile phase is passed through the neutralization reaction to collect substances at the pH boundary. In this method, separation and concentration are performed using Ito, and a patent has already been filed by Ito et al. (US Pat. Nos. 5,332,504 and 5,354,473, etc.)
[0010]
Monographs ("High-speed Countercurrent Chromatography", edited by Y. Ito and WD Conway, John Wiley & Sons, Inc., 1995) are also published and explained. As a result of the neutralization reaction in the column, the pH of the eluent shows a change in pH just as seen in neutralization titration. In the case of a mixture sample such as an organic acid, it can be eluted in order according to the pKa and distribution ratio of the sample. Further, it is possible to separate a sample of g order by high-speed countercurrent chromatography, which has been difficult until now.
[0011]
On the other hand, since the portion where the pH changes suddenly moves in the column, there is an advantage that a specific compound is enclosed at the boundary of the pH and can be concentrated at a large concentration rate of several tens of times or more. In this case, there is no diffusion of the sample as seen in ordinary chromatography, and the compound can be concentrated in a very small volume. Therefore, it can be used as an efficient concentration method for trace metal impurities in place of the conventional solvent extraction method, but there is no example of metal concentration. When concentrating the metal, the stationary phase may contain a complex-forming reagent (ligand). 2 and 3 show how a trace amount of metal is concentrated according to the present invention.
[0012]
FIG. 2 shows the state immediately after the experiment. When the apparatus is first rotated and an acid such as hydrochloric acid or nitric acid is used as the mobile phase, and when the sample is first introduced into the column, the metal ions or inorganic ions in the sample are in the column. It shows how it is concentrated at the tip. The zone indicated by the rectangle of III is a stationary phase, the main component is an organic solvent such as ether or heptane, a complex-forming reagent such as DEHPA (di-2ethylhexyl phosphate) as a ligand, ammonia for pH adjustment, etc. Contains alkali. Part II is a sample, and the pH is adjusted in advance with ammonia or the like so that metal ions contained in the sample are sufficiently extracted into the stationary phase. When precipitation due to metal ion hydroxide becomes a problem, a complexing agent such as tartaric acid or citric acid is added to the sample in advance to prevent precipitation. When the device is rotated, the part of the stationary phase III (organic phase) is lighter than the mobile phase (acid solution, part I indicated as MP in the figure). The column is moved to the column head (inlet side, left side in FIG. 2) by the Archimedes screw effect. Since the force to move is stronger as the rotation speed of the column increases, the stationary phase is held in the column without being pushed out even if the mobile phase is pumped under appropriate conditions. In this case, the retention rate of the stationary phase varies over the range of about 0 to 70% as a ratio of the stationary phase to the whole column. A constant value is obtained. That is, the rectangular portion of III does not move greatly, and is always present at a certain position in the column. Therefore, in the initial stage, the target ions gather at the column head shown in the dark at the left end of III. In the figure, hydrogen ions are omitted for simplicity, but M + (metal ions or inorganic ions) reacts or associates with R (complexing agent ions) and is extracted into the stationary phase. ing.
[0013]
FIG. 3 shows a state in which the concentrated metal ions and inorganic ions are further concentrated while repeating extraction and back-extraction across the pH boundary after all the sample is introduced into the column. . In FIG. 3, a rectangular zone combining II and III represents the stationary phase.
On the other hand, the mobile phase (MP) containing acid always flows from the head of the column to the tail (end, right direction) at a constant speed while in contact with the stationary phase. Three large arrows (HIGH) in the figure indicate the flow of the mobile phase. Since the mobile phase is acidic, it proceeds through the column while neutralizing alkali such as ammonia in the stationary phase. Of the stationary phase, the organic phase is already neutralized with acid in the trapezoidal portion indicated by II. Of the stationary phase, the part III on the right side has not yet completed the reaction with the acid and contains an alkali. The dark border between II and III indicates the region where the acid and alkali are just neutralized (pH boundary). Since sufficient agitation is performed in the column, it is considered that the pH boundary indicated by the dotted line in the figure exists even in the mobile phase.
[0014]
The boundary of pH proceeds in the same direction as the mobile phase, but the acid in the mobile phase and the alkali in the stationary phase proceed while reacting, so the speed becomes slower than the speed of the mobile phase. A small arrow (LOW) in the stationary phase indicates the direction of movement of the pH boundary. Therefore, the ion M + first concentrated in the column head moves through the stationary phase more slowly than the speed of the mobile phase, repeating extraction and back-extraction, centering on the pH boundary, as shown by the arrow circle in the figure. Go ahead. In part (II) after neutralization with acid, ions M + are back-extracted into the mobile phase (hydrogen ions are omitted in the figure). Since the mobile phase velocity is faster than the pH boundary migration rate, the back-extracted ions pass through the pH boundary. Upon passing, the pH rises rapidly, so it binds again with the ligand ion R - and is extracted into the stationary phase. The ion advances toward the end of the column while repeating this cycle many times. Therefore, unlike ordinary ion exchange and HPLC methods, there is no diffusion of ions in the column, so a very small amount of ions can be concentrated in a very narrow region, and the concentration rate can be increased.
[0015]
If the stationary phase or sample does not contain alkali, the ions travel through the column while being separated due to the difference in the distribution ratio between the stationary phase and the mobile phase. Is not concentrated because it is not present. Examples of separation have already been published in the paper (E. Kitazume, N. Sato, Y. Saito and Y. Ito, Anal. Chem., 65, 2255 (1993).
E. Kitazume, M. Bhatnagar and Y. Ito, Mutual.separation of rare earth elements by high-speed countercurrent chromatography, Proc.Internat.Trace Anal. Symposium, 103,1990 (in Sendai, Japan).
E. Kitazume, M. Bhatnagar and Y. Ito, J. Chromatogr., 538,133 (1991). And monograph (E. and WD Conway) High-Speed Countercurrent Chromatography (John Wiley & Sons, Inc.), 415-443 (1995)), and patent (Separation of rare earth elements and other compounds with high-speed countercurrent chromatography US Pat.No.5,215,664) (1993)).
[0016]
In FIG. 2 and FIG. 3, hydrogen ions are omitted for the sake of simplicity, but FIG. 4 shows an extraction state in consideration of hydrogen ions and an extraction reagent (DEHPA). Here, the metal ions are exemplified by trivalent cations such as lanthanides. The thick line indicates the wall surface of the column. The upper part (stationary phase) in the column contains DEHPA. DEHPA, abbreviated as HG, is known to be a dimer and react with trivalent cations. In the figure, when the liquid becomes acidic, the equilibrium shifts to the left, and the metal ions move to the mobile phase (water phase) side. On the other hand, when the liquid becomes alkaline, the equilibrium shifts to the right, and the metal ions move to the stationary phase (organic phase) side.
[0017]
FIG. 5 shows a system including a pump, an injector, a high-speed counter-current chromatograph, a detector, and the like. In the figure, 1-l2 is as follows.
1: ethyl alcohol, 2: ion exchange water, 3: eluent (hydrochloric acid, etc.), 4-1, 4-2, 4-3: flow path switching valve, 5: pump, 6: injector (sample), 7: Injector (stationary phase), 8: high-speed counter-current chromatograph, 9: detector, 10: outlet (connected or discarded to a fraction collector, etc.), 11: injector (standard sample), l2: ion-exchanged water The flow path switching valve (4-1) is switched to ethyl alcohol (1) and then water (2), and flowed at an appropriate flow rate by the pump (5), and the outlet ( Drain from 10) and wash the flow path and the column of the high-speed counter-current chromatograph (8). Thereafter, the flow path switching valve (4-1) is switched to the eluent (3), and at the same time, the flow path switching valve (4-2) is set to the discharge side to replace the inside of the pump with the eluent.
The pump is stopped, and the stationary phase is introduced into the loop of the injector (7), the sample whose pH is adjusted so that the target substance is sufficiently extracted into the stationary phase in the loop of the injector (6). The injectors (7) and (6) are switched so that the flow path of the eluent is on the introduction side.
[0018]
The high-speed counter-current chromatograph (8) is operated at a constant rotational speed exceeding 1000 rpm, and when the rotation is stabilized, the pump (5) starts feeding the eluent.
Connect the outlet to a fraction collector to obtain a concentrated fraction. Alternatively, the peak is monitored by the detector (9), and only the concentrated fraction is collected. Alternatively, the quantitative value is obtained directly from the detector signal. As the detector (9), an absorptiometer, a light scatterometer, a refractometer, or the like as used in a normal liquid chromatography (HPLC) is used. Alternatively, an atomic absorption spectrometer, an ICP emission spectrometer, an ICP-mass spectrometer, or the like is used.
In order to adjust the optimum flow rate to be introduced into the detector, ion exchange water (12) can be added to the flow path by opening and closing the flow path switching valve (4-3). When ion-exchanged water is introduced, when the detector itself does not have a pump for controlling the flow rate, a pump is inserted between the flow path switching valve (4-3) and the detector (9).
[0019]
【Example】
Hereinafter, examples will be described.
Example 1
FIG. 6 shows the result of concentration using this system with 10 ml of a 0.1M tartaric acid solution containing 2 ppb of Zn, Mg and Ca as samples. The sample was adjusted to pH 7.1 with aqueous ammonia. A Teflon tube having an inner diameter of 0.5 mm and an outer diameter of 1.5 mm was further wound around a drum (diameter: 100 mm, thickness: 50 mm) to form a concentration column. (The column length is about 10 m, the internal volume is about 2 ml, the revolution radius is 10 cm) The number of rotations of the high-speed countercurrent chromatograph was 1200 rpm. The eluent was 0.1 M hydrochloric acid solution containing 0.1 M tartaric acid, and the stationary phase was 0.6 ml heptane solution containing 0.2 M DEHPA and 0.18 M ammonia. In FIG. 6, the horizontal axis represents the volume of 0.1 M hydrochloric acid eluent, and the vertical axis represents the emission intensity from the detector (DCP emission spectroscopic analyzer). The pump flow rate was 0.1 ml / min during sample concentration and 1 ml / min during emission intensity measurement. The intensity of P sharply decreases from 13.8 ml to 14 ml of the eluent, indicating that a sharp change in pH occurs in this region. Since Mg and Ca peaks are observed around 14 ml, it can be seen that these elements are concentrated at the pH boundary. On the other hand, a peak of Zn is observed around 14.3 to 14.4 ml with a slight delay. This is because, in the case of Zn, elution is delayed because the ratio (distribution ratio) extracted into the organic phase is large even when the pH is reduced compared to other elements. This example shows that separation is possible as in normal chromatography if the distribution ratio is different. In addition, it shows that concentration that is impossible with ordinary chromatography is possible.
[0020]
Example 2
FIG. 7 shows the luminescence intensity when a 0.1M tartaric acid standard solution containing heavy metals such as Cd, Mn, Ni, and Cu is concentrated. The experimental conditions are the same as in Example 1. 10 ml of a solution containing 2 ppb each of Cd, Mn, Ni, and Cu was used as a sample and concentrated by this system. In FIG. 7, peaks appear for all four elements at an eluent volume of 14 ml where the emission intensity of P sharply decreases.
[0021]
Example 3
FIG. 8 shows the result of concentrating 10 ml of a sample prepared by adding tartaric acid to tap water to make a 0.1M tartaric acid solution and adjusting the pH to 8.0 with aqueous ammonia. The experimental conditions are the same as in Example 1. FIG. 8 shows the emission intensity for Zn, Mn, and Ca. It turns out that Ca and Zn are contained in large quantities compared with Mn.
[0022]
Example 4
FIG. 9 shows the results of concentration of Cd, Mn, Ni, and Cu in tap water. The experimental conditions are the same as in Example 1. Moreover, the same thing as the tap water sample in Example 3 is used. Sufficient emission intensity is obtained for Mn, Ni, and Cu. In order to examine the emission intensity profile of Cd in detail, FIG. 10 shows an enlarged view of the vertical axis of FIG. Cd was considered to be at a ppb level or lower in normal tap water, but a clear peak was confirmed.
[0023]
Table 1 shows an example of quantifying Cd, Mn, Ni, and Cu contained in trace amounts in tap water based on the peak area of the standard sample based on the concentration results of each element from Example 1 to Example 4.
[0024]
[Table 1]
Figure 0003756649
[0025]
Example 5
FIG. 11 shows the concentration results of Mn and Ni in the tap water sample. The sample is processed in the same manner as in Example 3. The experimental conditions are the same as in Example 1 except that the pump flow rate is 0.1 ml / min throughout the experiment. In this case, the flow rate entering the detector (DCP emission spectroscopic analyzer) was adjusted to about 1 ml / min by introducing ion-exchanged water from (12) in FIG. The eluent of the high-speed countercurrent chromatograph is 0.1 ml / min and is slowly introduced into the detector, indicating a more accurate emission profile. The peak width of the emission intensity is about 0.1 ml in this figure. In addition, since there is about 2 ml of dead space from the end of the stationary phase in the column to the detector, there is diffusion of the sample zone after concentration until it reaches the detector. Nevertheless, since the peak is finished in the range of about 0.1 ml of the eluent, it can be seen that the eluent is surely concentrated within 0.1 ml. Since the volume of the original sample is 10 ml, it can be seen that a concentration ratio of 100 times or more is achieved by the volume ratio.
[0026]
【The invention's effect】
According to the high-speed counter-current chromatograph of the present invention, a revolution radius of 10 cm or more and a high-speed rotation exceeding 1,000 rpm are possible, and metals such as Ca, Cd, Mg, Mn, Ni, Zn, Cu, and Pb are contained in 100 μl or less. It is possible to concentrate at a concentration rate of 100 times or more in a minute volume, and ultra-trace analysis becomes possible. In addition, the durability of the tube is large, and the column is easy to handle.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a schematic structure of a high-speed countercurrent chromatograph of the present invention.
FIG. 2 is an explanatory diagram showing a state in which metal ions in a sample are collected on a column head immediately after the start of concentration in a high-speed countercurrent chromatograph column.
FIG. 3 is an explanatory diagram showing the state of metal concentration at the pH interface in a high-speed counter-current chromatograph column.
FIG. 4 is an explanatory diagram showing extraction and back extraction of ions in a column of a high-speed countercurrent chromatograph.
FIG. 5 is an explanatory diagram showing a schematic configuration of an apparatus including a high-speed counter-current chromatograph.
FIG. 6 is a chromatogram showing the concentration results of standard solutions of Ca, Mg and Zn by high-speed countercurrent chromatograph.
FIG. 7 is a chromatogram showing the results of concentration of heavy metal standard solutions of Ca, Mg, Ni and Cu by high-speed countercurrent chromatograph.
FIG. 8 is a chromatogram showing the concentration results of Zn, Mn and Ca in a tap water sample by a high-speed countercurrent chromatograph.
FIG. 9 is a chromatogram showing the results of concentration of Cd, Mn, Ni and Cu in a tap water sample by a high-speed countercurrent chromatograph.
FIG. 10 is a chromatogram showing the concentration results of Cd and Ni in a tap water sample by a high-speed countercurrent chromatograph.
FIG. 11 is a chromatogram showing the result of concentration of Mn and Ni in a tap water sample by a high-speed countercurrent chromatograph.
[Explanation of symbols]
a Revolving shaft b Liquid conveying tube c Rotating shaft d Drum e-1 Gear e-2 Gear f Weight

Claims (7)

回転可能な支持体;該支持体に自転及び公転可能に取付けられ、且つ周囲に液体搬送及び濃縮用のチューブを巻いた、自転及び公転駆動されるドラム;前記チューブと連結させる液体搬送用のチューブ;該支持体に取付けられ、前記液体搬送用のチューブを軸内の通路に通した前記ドラムの公転軸;及び自転軸と公転軸を結合する回転同期機構;を有する高速向流クロマトグラフにおいて、公転軸受けと自転軸受けを回転ドラムの片側に配置してなることを特徴とする高速向流クロマトグラフ。A rotatable support; a drum for rotation and revolution which is attached to the support so as to rotate and revolve, and a tube for liquid conveyance and concentration is wound around the support; a tube for liquid conveyance connected to the tube; A high-speed countercurrent chromatograph having a revolution axis of the drum attached to the support and passing the tube for transporting the liquid through a passage in an axis; and a rotation synchronization mechanism coupling the rotation axis and the revolution axis; A high-speed countercurrent chromatograph comprising a revolving bearing and a rotating bearing arranged on one side of a rotating drum. 液体搬送用のチューブが、公転軸内を通って自転軸内へ連結される2本以上のチューブからなり、かつ互いに半回転以上捻じられたものである、請求項1記載のクロマトグラフ。The chromatograph according to claim 1, wherein the tube for transporting liquid is composed of two or more tubes connected to the rotation shaft through the revolution shaft, and twisted at least half a turn. ドラムの自転軸方向の厚みが100mm以下であり、公転半径が10cm以上で公転軸受けの回転数が1,000 rpmを超えるものである、請求項1又は2記載のクロマトグラフ。The chromatograph according to claim 1 or 2, wherein the drum has a thickness in the rotation axis direction of 100 mm or less, a revolution radius of 10 cm or more, and a revolution bearing having a rotation speed exceeding 1,000 rpm. 公転軸を取り付けた支持体に、振動ピックアップを設け、かつ公転軸を挟んで自転軸の反対側に重りを取付けてなる、請求項1〜3のいずれかに記載のクロマトグラフ。The chromatograph according to any one of claims 1 to 3, wherein a vibration pickup is provided on a support body to which a revolution shaft is attached, and a weight is attached to the opposite side of the rotation shaft across the revolution shaft. 重りの取付け位置を自転及び回転軸方向に2個所以上配置してなる、請求項4記載のクロマトグラフ。The chromatograph according to claim 4, wherein two or more weight attachment positions are arranged in the direction of rotation and rotation axis. 公転軸内を通して外部に引き出した液体搬送用のチューブに、液体の流路切り換えバルブ、液体搬送用ポンプ、及び試料とチューブ内に固定される固定相とを流路内に導入するためのインジェクターを取付けてなる、請求項1〜5のいずれかに記載のクロマトグラフ。A liquid flow path switching valve, a liquid transport pump, and an injector for introducing a sample and a stationary phase fixed in the tube into the flow path are provided in the liquid transport tube drawn outside through the revolution shaft. The chromatograph according to any one of claims 1 to 5, wherein the chromatograph is attached. 公転軸内を通して外部に引き出した液体搬送用のチューブの出口側に分析装置を接続してなり、濃縮目的元素の分析を連続的に行い、チューブ内の濃縮状態を監視し、かつ測定の開始時間、バルブの開閉タイミング又はポンプの流速を自動的に制御し得る、請求項1〜6のいずれかに記載のクロマトグラフ。The analyzer is connected to the outlet side of the tube for transporting the liquid drawn out through the revolution shaft, continuously analyzing the concentration target element, monitoring the concentration state in the tube, and starting time of measurement. The chromatograph according to any one of claims 1 to 6, which can automatically control opening and closing timing of a valve or a flow rate of a pump.
JP34954197A 1997-12-18 1997-12-18 High-speed counter-current chromatograph Expired - Fee Related JP3756649B2 (en)

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