JP4936536B2 - Quantitative and qualitative analysis methods - Google Patents
Quantitative and qualitative analysis methods Download PDFInfo
- Publication number
- JP4936536B2 JP4936536B2 JP2007183110A JP2007183110A JP4936536B2 JP 4936536 B2 JP4936536 B2 JP 4936536B2 JP 2007183110 A JP2007183110 A JP 2007183110A JP 2007183110 A JP2007183110 A JP 2007183110A JP 4936536 B2 JP4936536 B2 JP 4936536B2
- Authority
- JP
- Japan
- Prior art keywords
- substance
- dna
- quantitative
- working electrode
- qualitative analysis
- 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 - Fee Related
Links
Description
本発明は、Ａｕ膜等を利用して、例えばＤＮＡ等の定量・定性解析を行う電気化学的な分析方法等に関するものである。 The present invention relates to an electrochemical analysis method for performing quantitative / qualitative analysis of, for example, DNA using an Au film or the like.
Ａｕは耐腐食性に富み、しかも多種の有機物質に対する良好な吸着性を有することから、近年、Ａｕの表面に応答性物質を固定しておき、その応答性物質に対応する有機物質が当該応答物質に結合するときの、その応答物質の応答を捉えて有機物質を定量・定性分析する試みが盛んになされている。 Since Au is rich in corrosion resistance and has good adsorptivity to various organic substances, in recent years, a responsive substance has been fixed on the surface of Au, and the organic substance corresponding to the responsive substance has the response. Many attempts have been made to quantitatively and qualitatively analyze organic substances by capturing the response of the responding substance when bound to the substance.
その応答を捉える１つの方法としてＡｕ電位を測定する電気化学的な方法があり、ＤＮＡ、たんぱく質の検出を中心に研究が進められている。具体的に一例を説明すると、まず、検出したいＤＮＡ（以下Ｔ−ＤＮＡとも言う）を含有させたサンプル液に、前記ＤＮＡの相補ＤＮＡ（以下、Ｐ−ＤＮＡとも言う）を表面に固定化したＡｕ膜を浸す。そうすると、Ｔ−ＤＮＡがＰ−ＤＮＡとハイブリタイゼーションを起こす。このときＴ−ＤＮＡはリン酸基に負電荷を持っているので、Ａｕ膜近傍の電位が下がる。この電位変化を測定することで、Ｔ−ＤＮＡの定性・定量分析を行うことができる（特許文献１、２）。 There is an electrochemical method for measuring the Au potential as one method for capturing the response, and research is focused on detection of DNA and proteins. A specific example will be described. First, Au obtained by immobilizing DNA complementary to the DNA (hereinafter also referred to as P-DNA) on a surface of a sample solution containing DNA to be detected (hereinafter also referred to as T-DNA). Immerse the membrane. Then, T-DNA hybridizes with P-DNA. At this time, since T-DNA has a negative charge in the phosphate group, the potential in the vicinity of the Au film is lowered. By measuring this potential change, qualitative and quantitative analysis of T-DNA can be performed (Patent Documents 1 and 2).
ところで、実際にＡｕ膜の電位変化を精密に測定するためには、その信号の変化量がドリフト量に埋もれてしまわないように、できる限りＡｕ膜の電位を安定した状態にする必要がある。 By the way, in order to actually measure the potential change of the Au film accurately, it is necessary to make the potential of the Au film as stable as possible so that the change amount of the signal is not buried in the drift amount.
しかしながら、Ａｕは、電位が安定するまでに、図１に示すように通常でも１０時間以上を要し、非常に時間がかかるという不具合がある。これは測定での初期設定時のみならず、途中で液を交換する場合でも同様に生じる不具合である。なお図１中ＰＢはサンプル液であるリン酸緩衝液の略である。 However, Au has a disadvantage that it takes 10 hours or more normally until the potential is stabilized, as shown in FIG. This is a problem that occurs not only at the time of initial setting in measurement but also when the liquid is changed in the middle. In FIG. 1, PB is an abbreviation for a phosphate buffer solution which is a sample solution.
また、例えば、ハイブリタイゼーションを行わせる際に使用する溶液と、電位を測定する際に使用する溶液とが異なり、途中で液を交換する必要がある場合に、この液交換を行うだけでＡｕ電極の電位が変わり、実際に測定したい電位変化量を再現性よく精密に測定することができない。 In addition, for example, when the solution used for hybridization is different from the solution used for measuring the potential, it is necessary to change the solution in the middle. The potential of the electrode changes, and the amount of potential change actually measured cannot be accurately measured with good reproducibility.
ところで、測定に多くの時間を要し、液交換時等での再現性にも乏しいという不具合は金電極に限られたものではない。要は、化学的に安定であって、自らは酸化還元せずにサンプル液との間で電子の授受を行いうる元素で構成されている電極を使用した場合に同様に生じ得ることなのである。
そこで本発明は、この種の電気化学測定方法において、作用電極の電位安定を極めて短時間で行うことができ、再現性を向上させ、ひいては測定精度の向上に寄与することをその主たる所期課題としたものである。 Therefore, the main problem of the present invention is that in this type of electrochemical measurement method, the potential of the working electrode can be stabilized in a very short time, thereby improving reproducibility and, consequently, improving measurement accuracy. It is what.
すなわち、本発明に係る電気化学測定方法は、自らは酸化還元せずにサンプル液との間で電子の授受を行いうる元素で構成されており、なおかつ表面に所定の応答性物質が固定化されている作用電極を、前記サンプル液に浸すことにより、このサンプル液中に含まれる測定対象物質を前記応答性物質に応答させ、その結果生じる作用電極の電位変化を測定することで測定対象の定量及び／又は定性分析を行う方法であって、前記サンプル液に、前記測定対象物質とは反応しない酸化還元物質を含有させることを特徴とするものである。 That is, the electrochemical measurement method according to the present invention is composed of an element that can exchange electrons with a sample solution without being oxidized / reduced, and a predetermined responsive substance is immobilized on the surface. The working electrode is immersed in the sample liquid, the measurement target substance contained in the sample liquid is caused to respond to the responsive substance, and the resulting potential change of the working electrode is measured to quantify the measurement target. And / or a qualitative analysis method, characterized in that the sample liquid contains a redox substance that does not react with the substance to be measured.
このようなものであれば、加えた酸化還元物質が作用電極との間で酸化又は還元反応を惹起して作用電極の電位を短時間で安定させることとなる。その結果、測定時間を短縮でき、しかも液交換時等における電位再現性も大きく向上する。なお、酸化還元物質を大量に入れるとその作用で電位が主として定まってしまい、応答性物質の応答による電位変化を測定できなくなる。したがって、酸化還元物質は、応答性物質の応答による電位変化を阻害しない程度にサンプル液に含有させるのが好ましい。その具体的な量は、酸化還元物質の種類にもよるが、数ｎｍｏｌ／ｌ〜数ｍｍｏｌ／ｌくらいがよく、より好適には数百ｎｍｏｌ／ｌ、さらに好ましくは約１００ｎｍｏｌ／ｌ又はそれ以下がよい。 In such a case, the added redox substance causes an oxidation or reduction reaction with the working electrode and stabilizes the potential of the working electrode in a short time. As a result, the measurement time can be shortened, and the potential reproducibility at the time of liquid exchange is greatly improved. If a large amount of the redox substance is added, the potential is mainly determined by the action, and the potential change due to the response of the responsive substance cannot be measured. Therefore, the redox substance is preferably contained in the sample solution to the extent that the potential change due to the response of the responsive substance is not inhibited. The specific amount depends on the kind of the redox substance, but may be several nmol / l to several mmol / l, more preferably several hundred nmol / l, more preferably about 100 nmol / l or less. Is good.
本発明の効果が特に顕著に発揮される測定対象物質としては、たんぱく質、核酸、アミノ酸等の生体構成分子を挙げることができる。 Examples of the measurement target substance that exhibits the effects of the present invention particularly remarkably include biological constituent molecules such as proteins, nucleic acids, and amino acids.
より具体的には、前記測定対象物質としてＤＮＡを挙げることができる。この場合前記応答性物質は、前記ＤＮＡの相補ＤＮＡにすればよい。こうすることで、それらＤＮＡ及び相補ＤＮＡがハイブリタイゼーションを引き起こす際の作用電極の電位変化を測定することができる。 More specifically, DNA can be mentioned as the measurement target substance. In this case, the responsive substance may be a complementary DNA of the DNA. By doing so, the potential change of the working electrode when the DNA and complementary DNA cause hybridization can be measured.
ＤＮＡやＲＮＡのハイブリタイゼーション以外の応答反応としては、複合体を形成する一対の分子、例えば抗原−抗体反応、糖−レクチン、リガンド−レセプタ、ビオチン−アビジン、酵素−基質等を挙げることができる。すなわち、対分子のいずれかを作用電極に応答性物質として固定化しておき、対応する他方の対分子（測定対象物質）が反応を起こして結合する際の電位変化を測定すればよい。言うまでもないが、このとき測定対象物質は電荷を持つなど、結合によって作用電極に電位変化をもたらすものである必要がある。 Examples of response reactions other than DNA and RNA hybridization include a pair of molecules forming a complex, such as antigen-antibody reaction, sugar-lectin, ligand-receptor, biotin-avidin, enzyme-substrate, and the like. . That is, any one of the counter molecules may be immobilized on the working electrode as a responsive substance, and the potential change when the corresponding counter molecule (measurement target substance) reacts and binds may be measured. Needless to say, at this time, the substance to be measured needs to bring about a potential change in the working electrode by binding, such as having a charge.
前記作用電極を構成する元素としては、代表的にはＡｕが好適である。生体構成分子を測定する場合に、その応答性物質を、チオール基を介して簡単に固定化できるからである。その他の元素としては、Ｐｔ、Ａｇ等の貴金属類や、Ｃ、或いはＴｉ、Ｗ、Ｓｎ、Ｉｎ又はＩｒなどを挙げる事ができる。 As the element constituting the working electrode, Au is typically suitable. This is because the responsive substance can be easily immobilized via a thiol group when measuring a biological constituent molecule. Examples of other elements include noble metals such as Pt and Ag, C, Ti, W, Sn, In, and Ir.
前記酸化還元物質は、基本的にどのようなものでも構わない。作用電極との反応において可逆性は必要なく、要は、作用電極を構成する元素との関係でより電位安定に優れたものがよい。その一方で、測定対象物質や応答性物質と反応してこれを変質させるようなものは除かれる。作用電極がＡｕの場合は、フェリシアン化カリウムやフェロシアン化カリウム、Ｈ２Ｏ２、アスコルビン酸等が望ましい。その他に、ベンゾキノンやハイドロキノンなどのキノン類、あるいはジチオスレイトール等のチオール類も、この発明で使用可能な酸化還元物質として挙げられる。ただし、例えば作用電極にＡｕを用い、ＤＮＡ等の応答性物質をチオール結合させる場合には、酸化還元物質としてチオール類を選択すると、応答性物質には好ましくない（置換することがある）が、チオール結合以外の方法により応答性物質を作用電極に固定した場合には、電位安定のための酸化還元物質としてチオール類は好適なものとなる。 The redox material may be basically any type. There is no need for reversibility in the reaction with the working electrode, and in short, a material having better potential stability in relation to the elements constituting the working electrode is preferable. On the other hand, those that react with the substance to be measured or the responsive substance to alter it are excluded. When the working electrode is Au, potassium ferricyanide, potassium ferrocyanide, H 2 O 2 , ascorbic acid and the like are desirable. In addition, quinones such as benzoquinone and hydroquinone, and thiols such as dithiothreitol are also included as redox substances that can be used in the present invention. However, for example, when Au is used for the working electrode and a responsive substance such as DNA is thiol-bonded, selecting a thiol as the redox substance is not preferable for the responsive substance (may be substituted), When the responsive substance is immobilized on the working electrode by a method other than thiol bonding, thiols are suitable as redox substances for stabilizing the potential.
酸化還元物質毎の具体的な好ましい濃度としては、電子吸引性のあるフェリシアン化カリウム、Ｈ２Ｏ２の場合は、約４０μｍｏｌ／ｌ〜７ｍｍｏｌ／ｌである。一方、電子吸引性のあるフェロシアン化カリウム、アスコルビン酸では、約５μｍｏｌ／ｌ〜５００μｍｏｌ／ｌが好ましい。実験データから、この範囲以上の酸化還元物質を添加しても、電位安定機能が飽和して、逆に測定対象物質の電位変化を阻害する恐れがあり、この範囲以下であると、電位安定機能が十分に機能しないと考えられる。 A specific preferable concentration for each oxidation-reduction substance is about 40 μmol / l to 7 mmol / l in the case of potassium ferricyanide having electron withdrawing property and H 2 O 2 . On the other hand, in the case of potassium ferrocyanide and ascorbic acid having electron withdrawing property, about 5 μmol / l to 500 μmol / l is preferable. From experimental data, even if an oxidation-reduction substance exceeding this range is added, the potential stabilization function may be saturated and, on the contrary, the potential change of the measurement target substance may be inhibited. Is not expected to work well.
このような構成の本発明によれば、加えた酸化還元物質が作用電極との間で酸化又は還元反応を惹起して作用電極の電位を短時間で安定させることとなる。その結果、測定時間を短縮でき、しかも液交換時等における電位再現性も向上する。 According to the present invention having such a configuration, the added redox substance causes an oxidation or reduction reaction with the working electrode, and the potential of the working electrode is stabilized in a short time. As a result, the measurement time can be shortened, and the potential reproducibility at the time of liquid exchange is improved.
以下に本発明の一実施形態について図面を参照して説明する． An embodiment of the present invention will be described below with reference to the drawings.
この実施形態に係る測定装置１は、図２に示すように、サンプル液等の液体を収容するセル２と、セル２内の液に浸漬させる比較電極３及び作用電極４と、それら電極３、４間の電圧を検出する電圧検出機構５とを備えたものであり、セル２内に測定対象物質であるＴ−ＤＮＡを含有させたサンプル液６を入れ、比較電極３に対する作用電極４の電位を前記電圧検出機構５で測定するように構成している。 As shown in FIG. 2, the measuring apparatus 1 according to this embodiment includes a cell 2 that contains a liquid such as a sample liquid, a comparison electrode 3 and a working electrode 4 that are immersed in the liquid in the cell 2, and the electrodes 3, 4 is provided with a voltage detection mechanism 5 for detecting a voltage between 4, a sample solution 6 containing T-DNA as a measurement target substance is placed in the cell 2, and the potential of the working electrode 4 with respect to the comparison electrode 3 Is measured by the voltage detection mechanism 5.
しかして、作用電極４にはＡｕ電極を用いており、その表面にチオール基を介して応答性物質であるＰ−ＤＮＡを固定している。また、前記サンプル液６には、さらにＡｕ電極４に対する酸化還元物質である微量（ここでは約１００ｎｍｏｌ／ｌ）のアスコルビン酸を含有させている。なお、後述するデータでは、Ａｕ電極４の電位を電位測定デバイス（ＩＳＦＥＴ、Ｃｈｅｍｉｃａｌ Ｃｈａｒｇｅ ｃｏｕｐｌｅｄ ｄｅｖｉｃｅ（ケミカルＣＣＤ）等）を用いて増幅した電位を表示するようにしている。 Therefore, an Au electrode is used as the working electrode 4, and P-DNA, which is a responsive substance, is immobilized on the surface of the working electrode 4 via a thiol group. The sample solution 6 further contains a trace amount (about 100 nmol / l) of ascorbic acid, which is a redox substance for the Au electrode 4. In the data to be described later, the potential obtained by amplifying the potential of the Au electrode 4 using a potential measuring device (such as ISFET or Chemical Charge coupled device (chemical CCD)) is displayed.
次に、このような構成した装置１を用いて実際に測定を行った実施例につき、データを参考にして説明する。 Next, an example of actual measurement using the apparatus 1 configured as described above will be described with reference to data.
図３は、Ａｕ電極の安定時間を、サンプル液（リン酸緩衝液）にアスコルビン酸を含有させた場合とさせていない場合で比較した出力電圧の時系列データを示している。なお、この測定では、再現性をみるために２チャンネル（ＣＨ１、ＣＨ２）で測定している。 FIG. 3 shows time series data of the output voltage in which the stabilization time of the Au electrode is compared between when the sample solution (phosphate buffer solution) contains ascorbic acid and when it is not. In this measurement, measurement is performed with two channels (CH1, CH2) in order to see reproducibility.
このデータからアスコルビン酸がない状態では、液交換前後のドリフトは１分間では測定に十分な程度には安定しない。しかもＣＨ１とＣＨ２で大きく電位が異なっていることから、再現性に乏しいことがわかる。一方、アスコルビン酸を入れた方は、ドリフト量、液交換時電位再現性ともに飛躍的に性能が向上していることがわかる。したがって、この方法を活用すれば、ドリフトが安定するまでの時間を大幅に短縮でき、また液交換時の電位再現性も改善して、ＤＮＡの定量・定性分析を迅速かつ正確に行うことができる。 From this data, in the absence of ascorbic acid, the drift before and after the liquid exchange is not stable enough for measurement in 1 minute. Moreover, since the potentials are greatly different between CH1 and CH2, it can be seen that the reproducibility is poor. On the other hand, it can be seen that the performance with the ascorbic acid drastically improved in both the drift amount and the potential reproducibility during liquid exchange. Therefore, if this method is used, the time until the drift stabilizes can be greatly shortened, and the potential reproducibility at the time of liquid exchange can be improved, so that the quantitative and qualitative analysis of DNA can be performed quickly and accurately. .
酸化還元物質の電位安定化機能を示す他のデータとして、図４、図５を挙げる。
図４はフェロシアン化カリウム添加によるＡｕ電極の電位変化を示す。また、図５に各種の酸化還元物質の追加によるＡｕ電極の出力濃度変化の濃度依存性を示す。
FIG. 4 and FIG. 5 are given as other data showing the potential stabilizing function of the redox substance.
FIG. 4 shows the change in potential of the Au electrode due to the addition of potassium ferrocyanide. FIG. 5 shows the concentration dependence of the change in the output concentration of the Au electrode due to the addition of various redox substances.
実験結果において、Ｋ３[Ｆｅ（ＣＮ）６]とＨ２Ｏ２の添加では、４５．５μｍｏｌ／ｌ〜６．７１ｍｍｏｌ／ｌの濃度範囲で飽和曲線型の濃度依存性を示した。これはその電子吸引性によりＡｕ薄膜（Ａｕ電極）中の電子を抜き取る為と考えられる。また、電子供与性のＫ４[Ｆｅ（ＣＮ）６]やアスコルビン酸の添加では５．５μｍｏｌ／ｌ〜５００μｍｏｌ／ｌの濃度範囲において出力減少が見られ、その後ほぼ飽和することが示された。このことは、これら酸化還元物質を大量に入れても飽和してその電位安定効果にそれ以上寄与することはなく、実際の測定では、少なくとも前記範囲（非飽和領域内）で用いることが必要であることを示している。 In the experimental results, the addition of K 3 [Fe (CN) 6 ] and H 2 O 2 showed a saturation curve type concentration dependency in the concentration range of 45.5 μmol / l to 6.71 mmol / l. This is thought to be due to extraction of electrons in the Au thin film (Au electrode) due to the electron withdrawing property. Further, it was shown that when electron donating K 4 [Fe (CN) 6 ] or ascorbic acid was added, the output decreased in the concentration range of 5.5 μmol / l to 500 μmol / l, and then almost saturated. This means that even if a large amount of these redox substances are added, they will saturate and do not contribute further to the potential stabilization effect. In actual measurement, it is necessary to use at least the above range (in the non-saturated region). It shows that there is.
その他，本発明は、各説明の構成を適宜組み合わせるなど、その趣旨を逸脱しない範囲で種々変形が可能である。 In addition, the present invention can be variously modified without departing from the spirit of the present invention, for example, by appropriately combining the configurations of the descriptions.
３ ・・・比較電極
４ ・・・作用電極（Ａｕ電極）
６ ・・・サンプル液
3 ... Comparative electrode 4 ... Working electrode (Au electrode)
6 ・ ・ ・ Sample liquid
Claims (5)
前記サンプル液に、前記測定対象物質とは反応しない酸化還元物質を含有させ、かつ、
前記酸化還元物質が、アスコルビン酸、フェロシアン化カリウム又はフェリシアン化カリウムであることを特徴とする定量及び／又は定性分析方法。 By immersing a working electrode, which is composed of an element capable of transferring electrons to and from the sample solution without being oxidized / reduced, and has a predetermined responsive substance immobilized on the surface thereof, in the sample solution. A method for quantifying and / or qualitatively analyzing a measurement target substance that is configured to measure a potential change of a working electrode, which is generated in response to the responsive substance, in the measurement target substance contained in the sample liquid,
The sample solution contains a redox substance that does not react with the substance to be measured ; and
The quantitative and / or qualitative analysis method characterized in that the redox substance is ascorbic acid, potassium ferrocyanide or potassium ferricyanide .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007183110A JP4936536B2 (en) | 2006-07-13 | 2007-07-12 | Quantitative and qualitative analysis methods |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2006193351 | 2006-07-13 | ||
| JP2006193351 | 2006-07-13 | ||
| JP2007183110A JP4936536B2 (en) | 2006-07-13 | 2007-07-12 | Quantitative and qualitative analysis methods |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2008039773A JP2008039773A (en) | 2008-02-21 |
| JP4936536B2 true JP4936536B2 (en) | 2012-05-23 |
Family
ID=39174922
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2007183110A Expired - Fee Related JP4936536B2 (en) | 2006-07-13 | 2007-07-12 | Quantitative and qualitative analysis methods |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4936536B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114486872B (en) * | 2022-01-27 | 2024-01-19 | 巨进科 | Semi-quantitative detection method and application of ascorbic acid in wheat flour |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3175022B2 (en) * | 1992-01-29 | 2001-06-11 | 東亜ディーケーケー株式会社 | pH measuring device and its calibration method |
| JP3175021B2 (en) * | 1992-01-29 | 2001-06-11 | 東亜ディーケーケー株式会社 | Method and apparatus for stabilizing the potential of a pH measurement electrode |
| JPH09138213A (en) * | 1995-11-15 | 1997-05-27 | Sangi Co Ltd | Immunosensor |
| RU2161653C2 (en) * | 1998-08-24 | 2001-01-10 | ФАРМАКОВСКИЙ Дмитрий Александрович | Method of quantitative electrochemical analysis of biological molecules |
| JP2004028887A (en) * | 2002-06-27 | 2004-01-29 | Yamaguchi Technology Licensing Organization Ltd | Development of cholesterol sensor utilizing molecule mold membrane and non-invasion cholesterol measuring method and equipment using the cholesterol sensor |
| JP2005077210A (en) * | 2003-08-29 | 2005-03-24 | National Institute For Materials Science | Biomolecule detecting element and nucleic acid analyzing method using it |
| JP4734234B2 (en) * | 2004-03-24 | 2011-07-27 | 独立行政法人科学技術振興機構 | Measuring method and system for detecting morphology and information related to biomolecules using IS-FET |
| JP3874772B2 (en) * | 2004-07-21 | 2007-01-31 | 株式会社日立製作所 | Biologically related substance measuring apparatus and measuring method |
| JP4604176B2 (en) * | 2004-08-17 | 2010-12-22 | 独立行政法人産業技術総合研究所 | Sensor device for measuring surface potential |
| JP4744910B2 (en) * | 2004-11-11 | 2011-08-10 | 株式会社堀場製作所 | Biosensor, multibiosensor, and multicomponent measurement system using the same |
-
2007
- 2007-07-12 JP JP2007183110A patent/JP4936536B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2008039773A (en) | 2008-02-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Alizadeh et al. | Selective determination of chloramphenicol at trace level in milk samples by the electrode modified with molecularly imprinted polymer | |
| O'Shea et al. | Chemically modified microelectrodes for capillary electrophoresis/electrochemistry | |
| CN101180403B (en) | Oxidizable species as an internal reference in control solutions for biosensors | |
| Brett et al. | Electrochemical sensing in solution—origins, applications and future perspectives | |
| Dilgin et al. | Electrocatalytic oxidation of sulphide using a pencil graphite electrode modified with hematoxylin | |
| Temerk et al. | Square wave cathodic adsorptive stripping voltammetric determination of the anticancer drugs flutamide and irinotecan in biological fluids using renewable pencil graphite electrodes | |
| Majidi et al. | Sensing L-cysteine in urine using a pencil graphite electrode modified with a copper hexacyanoferrate nanostructure | |
| Uludag et al. | Design and characterisation of a thin-film electrode array with shared reference/counter electrodes for electrochemical detection | |
| Omidinia et al. | Aptamer-based biosensor for detection of phenylalanine at physiological pH | |
| Gumpu et al. | Design and development of amperometric biosensor for the detection of lead and mercury ions in water matrix—a permeability approach | |
| US20210055260A1 (en) | Differential circuit for background correction in electrochemical measurements | |
| Medina-Sánchez et al. | On-chip electrochemical detection of CdS quantum dots using normal and multiple recycling flow through modes | |
| Li et al. | Molecularly imprinted electrochemical luminescence sensor based on enzymatic amplification for ultratrace isoproturon determination | |
| JP5215390B2 (en) | Electrochemical detection of silica species | |
| Hart et al. | Development of disposable amperometric sulfur dioxide biosensors based on screen printed electrodes | |
| Gross et al. | Nitrite/nitrate detection in serum based on dual-plate generator–collector currents in a microtrench | |
| Vasjari et al. | Amino acid determination using screen-printed electrochemical sensors | |
| US7198708B2 (en) | Electrochemical biosensor | |
| Chiu et al. | A disposable screen-printed silver strip sensor for single drop analysis of halide in biological samples | |
| Mori et al. | Amperometric detection with microelectrodes in flow injection analysis: theoretical aspects and application in the determination of nitrite in saliva | |
| JP4936536B2 (en) | Quantitative and qualitative analysis methods | |
| Tomčı́k et al. | Determination of pharmaceutical dosage forms via diffusion layer titration at an interdigitated microelectrode array | |
| González-López et al. | Electrochemical micropipette-tip for low-cost environmental applications: Determination of anionic surfactants through their interaction with methylene blue | |
| Bobrowski et al. | Catalytic adsorptive stripping chronopotentiometric determination of hexavalent chromium at a silver amalgam film electrode of prolonged application | |
| Torre et al. | A do-it-yourself electrochemical cell based on pencil leads and transparency sheets: Application to the enzymatic determination of histamine |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A711 | Notification of change in applicant |
Free format text: JAPANESE INTERMEDIATE CODE: A711 Effective date: 20100709 |
|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20100712 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A821 Effective date: 20100712 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20100720 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20111116 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20111206 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20120117 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20120207 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20120220 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20150302 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |