JP4340376B2 - Molecular film and non-electrolytic substance detection method - Google Patents
Molecular film and non-electrolytic substance detection method Download PDFInfo
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Description
【0001】
【発明の属する技術分野】
本発明は、辛味や甘味を呈する非電解物質を高感度に検出するための技術に関する。
【0002】
【従来の技術】
飲食物等の味の評価を行うために、脂質等からなる分子膜をセンサとして用いる方法が従来から提案されている。
【0003】
このような目的で使用されている従来の分子膜は、例えばPVC(ポリ塩化ビニル)等の高分子材と、脂質(例えば第四級アンモニウム塩)等の両親媒性物質または苦味物質と、可塑材とを所定の割合で混合して膜状に形成したものであり、液に浸けたときにその液内の物質成分に応じて膜電位が変化する。
【0004】
このような分子膜の応答特性は、一般的に各味物質に対して顕著な選択性を有していないため、検査対象に含まれる味物質を分析するような場合には、分子膜の成分の混合比や物質が異なる複数の分子膜を用いて同一の検査対象を測定し、得られた測定結果から検査対象に含まれる各味物質の量等を解析していた。
【0005】
【発明が解決しようとする課題】
しかしながら、従来の分子膜を用いた検査では、非電離質の辛味物質や甘味物質の検出感度が低く、特に、辛味物質については全く検出することができないという問題があった。
【0006】
本発明は、この問題を解決して、非電解物質の検出を高感度に行える分子膜および非電解質検出方法を提供することを目的としている。
【0007】
【課題を解決するための手段】
前記目的を達成するために、本発明の請求項1の分子膜は、高分子材と、電荷をもたない第1可塑剤と、電荷をもつ第2可塑剤とを所定の割合で混合して形成され、前記第2可塑剤と逆極性の電荷を有する脂質の吸着によって膜電位が変化する。
【0008】
また、本発明の請求項2の分子膜は、請求項1の分子膜において、
前記高分子材約800mgに対して、前記第1可塑剤が400〜3000μl、前記第2可塑剤が1〜20μlの割合で含まれていることを特徴としている。
【0009】
また、本発明の非電解物質検出方法は、
前記請求項1記載の分子膜を用いて、液中の非電解物質を検出する非電解物質検出方法であって、
前記検出対象の非電解物質を含まない第1基準液に前記分子膜を浸けて、膜電位を測定する第1測定段階と、
前記第1基準液と同質の液に前記分子膜と反対の極性の電荷をもつ脂質が添加された第2基準液に前記分子膜を浸ける段階と、
前記第2基準液に浸けた前記分子膜を前記第1基準液に浸けて、膜電位を測定する第2測定段階と、
前記第1測定段階で得られた膜電位と前記第2測定段階で得られた膜電位の差を基準値として求める段階と、
前記分子膜を洗浄する段階と、
前記洗浄した分子膜を前記第1基準液に浸けて、膜電位を測定する第3測定段階と、
前記第2基準液に添加した脂質と同物質が添加された検査対象液に前記分子膜を浸ける段階と、
前記検査対象液に浸けた前記分子膜を前記第1基準液に浸けて、膜電位を測定する第4測定段階と、
前記第3測定段階によって得られた膜電位と前記第4測定段階によって得られた膜電位の差を検査値として求める段階と、
前記基準値と検査値とから、前記検査対象液中の非電解物質を検出する段階とを含むことを特徴としている。
【0010】
【発明の実施の形態】
以下、図面に基づいて本発明の実施の形態を説明する。
図1は、本発明の実施の形態の非電解物質検出方法を行うためのシステムを示している。
【0011】
このシステムは、基準液や検査対象液等を入れるための容器11と、参照電極12と、分子膜センサ15と、参照電極12の電位を基準として分子膜センサ15の電位を検出する電圧検出器20と、電圧検出器20の出力をディジタル値に変換するA/D変換器21と、A/D変換器21の出力に対する記憶、演算等の処理を行うための演算装置22と、演算装置22の処理結果を出力する出力装置22とによって構成されている。
【0012】
参照電極12および分子膜センサ15は、容器11に入れた液体に浸けて使用するものであり、参照電極12の表面は、液体内の脂質等に反応しないように、KCl(塩化カリウム)100mmolを寒天で固定した緩衝層13で覆われており、上端にリード線12aが接続されている。
【0013】
また、分子膜センサ15は、アクリル等の基材16の表面に分子膜17がその一面側を露呈させた状態で固定されており、その反対面には、参照電極12の緩衝層13と同等の緩衝層18を介して電極19が設けられており、この電極19にリード線15bが接続されている。
【0014】
この分子膜17は、従来の分子膜のように種々の味物質に応答することがないように脂質や苦味物質を含まず、電荷を持たない第1可塑材と、電荷をもつ第2可塑剤と、膜のベースとなる高分子材とを所定の割合で混合して作製したものである。
【0015】
例えば、高分子材PVC(ポリ塩化ビニル)と、第1可塑剤として電荷をもたないDOPP(ジオクチルフェニルフォスフォネート)と、第2可塑剤としてマイナスの電荷をもつDOPPモノエステル体とを混合したもの約800mgを、THF10ccに溶解し、平底の容器(例えば直径85mmのシャーレ)に移し、これを均一な加熱されたプレート上で約30度Cに2時間保って、THFを揮散させることで、厚さ約200μmの分子膜17を得ている。
【0016】
また、高分子材、第1可塑剤、第2可塑剤の混合割合いは、高分子材約800mgに対して、第1可塑材が400〜3000μl、第2可塑材が1〜20μlにしており、このように作製した分子膜17に対しては、塩味物質、酸味物質、旨味物質、甘味物質、苦味物質、渋味物質および辛味物質の基本味物質は吸着せず、脂質分子のみが吸着性を示すことが確認されている。
【0017】
即ち、この分子膜17は、従来の分子膜とは全く異なり、基本の味物質に対して応答性が無く、液中の脂質に対してのみ応答性を有している。
【0018】
なお、実際の測定の際には、測定条件等が変わらないように、支持材(図示せず)によって基準電極12と分子膜センサ15の間隔を一定にしている。
【0019】
参照電極12の電位を基準とする分子膜17の膜電位は、電圧検出器20によって検出され、その膜電位がA/D変換器21によってディジタル値に変換されて演算装置22へ出力され、記憶、演算処理がなされ、その処理結果が出力装置23から出力される。
【0020】
次に、この分子膜17と前記システムを用いて検査対象液内の辛味物質や甘味物質等の非電解物質を検出するための非電解物質検出方法の手順を、図2のフローチャートにしたがって説明する。
【0021】
なお、この検出方法では、検出対象の非電解物質を含まず、人の唾液に相当する無味の第1基準液と、この第1基準液と同質の液体に、分子膜17と反対の極性(前記したように第2可塑剤がマイナス)の電荷をもつ脂質、例えばプラス電荷のTOMA(トリオクチルメチルアンモニウムクロリド)を所定濃度(1ppm)で添加した第2基準液とを用いている。第1基準液としては、例えばKCl(塩化カリウム)30mM+酒石酸0.3mM溶液を用いている。
【0022】
また、検査対象液にも、第2基準液と同様に、分子膜17と反対の極性の電荷をもつ脂質TOMAを同一濃度で添加している。
【0023】
始めに、参照電極12および分子膜センサ15を第1基準液に浸けて、膜電位Vaを測定して記憶する(S1:第1測定段階)。
【0024】
次に、参照電極12および分子膜センサ15を第2基準液に所定時間浸けてから(S2)、第1基準液に戻して、膜電位Vbを測定して記憶する(S3:第2測定段階)。
【0025】
そして、第1測定段階で得られた膜電位Vaと第2測定段階で得られた膜電位Vbの差ΔV=Vb−Vaを基準値として算出して記憶してから(S4)、参照電極12および分子膜センサ15を洗浄する(S5)。
【0026】
この洗浄には、例えば30パーセントエタノール+100mMHClの洗浄液を用いている。
【0027】
次に、洗浄した参照電極12および分子膜センサ15を再び第1基準液に浸けて、膜電位Vcを測定して記憶してから(S6:第3測定段階)、脂質が添加されている検査対象液に所定時間浸ける(S7)。
【0028】
そして、この検査対象液に浸けた参照電極12および分子膜センサ15を第1基準液に戻して、膜電位Vdを測定して記憶する(S8:第4測定段階)。
【0029】
続いて、第3測定段階によって得られた膜電位Vcと第4測定段階によって得られた膜電位Vdの差ΔV′を検査値として算出して記憶する(S9)。
【0030】
最後に、基準値ΔVと検査値ΔV′とから、脂質の吸着に対する検査対象液中の物質の影響度Pを求める(S10)。
【0031】
なお、この影響度Pは、例えば次の演算によって求める。
P=(ΔV′/ΔV)−1
【0032】
図3は、高分子材PVC約800mgに対して、第1可塑材(DOPP)が1000μl、第2可塑材(DOPPのモノエステル体)が10μlの割合で混合して形成した分子膜17を用いて、以下の6種類のサンプル液A〜Fについて、上記処理を1サンプル当たり5回ずつ行って平均を求めた結果を示している。
【0033】
サンプル液A(辛味):KCl(30mM)+酒石酸(0.3mM)+カプサイシン(10μM)
サンプル液B(塩味):KCl(300mM)+酒石酸(0.3mM)
サンプル液C(酸味):KCl(30mM)+酒石酸(3.0mM)
サンプル液D(甘味):KCl(30mM)+酒石酸(0.3mM)+蔗糖(1M)
サンプル液E(旨味):KCl(30mM)+酒石酸(0.3mM)+MSG(10mM)
サンプル液F(苦味):KCl(30mM)+酒石酸(0.3mM)+塩酸キニーネ(0.1mM)
なお、これらのサンプル液は人の感じる領域の中間の濃度に設定している。
【0034】
図3から明らかなように、非電解物質を含むサンプル液A、Dについての影響度Pは負の値で、しかもその絶対値は他のサンプル液の影響度の絶対値より格段に大きい。
【0035】
したがって、上記検出方法を用いることで、非電解物質を高感度に検出することができる。
【0036】
ここで、辛味や甘味の非電解物質を含むサンプル液A、Dのように、影響度Pが負になるということは、基準値ΔVより検査値ΔV′の方が小さいということであり、これは、第2基準液に分子膜17を浸けたときの液中物質の吸着度合いより、検査対象液に分子膜17を浸けたときの液中物質の吸着度合いの方が少ないということを示している。
【0037】
前記したように、分子膜17は基本的な味物質自体に感応せず、脂質(TOMA)にのみ感応するから、上記の吸着度合いの減少は、添加したTOMAの分子膜17への吸着を、辛味物質や甘味物質が抑制していることを示している。
【0038】
なお、辛味物質による脂質(TOMA)の吸着抑制作用は、液中で辛味物質自体が脂質(TOMA)に結合することによって生じ、甘味物質による脂質(TOMA)の吸着抑制作用は、甘味物質が分子膜17の表面を覆って辛味物質の分子膜への吸着を妨害していることによって生じるものと推測される。
【0039】
この分子膜17に対する脂質(TOMA)の吸着抑制作用は、塩味物質を含むサンプル液B、旨味物質を含むサンプル液E、苦味物質を含むサンプル液Fでも現れているが、その程度は非電解物質を含むサンプル液A、Dに比べて格段に低い。
【0040】
また、塩味物質を含むサンプル液Cのように、影響度Pが正になるということは、基準値ΔVより検査値ΔV′の方が大きいということであり、これは第2基準液に分子膜17を浸けたときの液中物質の吸着度合いより、検査対象液に分子膜17を浸けたときの液中物質の吸着度合いの方が大きいということを示している。つまり、塩味物質には、分子膜17に対する脂質の吸着を増長させる作用があることになる。
【0041】
このように、基本の味物質に対する応答性をもたない分子膜17を用いることで、検査対象液に添加された脂質の分子膜への吸着に対する味物質の影響度を把握することができる。
【0042】
また、成分が未知の検査対象液に対して上記測定を行ったときに、大きなマイナスの影響度Pが得られた場合、その検査対象液に大きな分子の非電解物質が含まれている可能性が高いと予想でき、逆にプラスの影響度Pが得られた場合には、その検査対象液に大きな分子の非電解物質が含まれている可能性が低いと予想できる。また、小さな分子の非電解質が含まれているとも予想される。それは、小さな分子の非電解質は、添加される脂質と疎水結合し、添加された脂質の疎水性がほどよく強くなり、分子膜への吸着が強くなると考えられるからである。
【0043】
また、予め非電解物質の濃度が異なる複数のサンプル液について前記測定を行って非電解物質の濃度と影響度との関係を求めておけば、非電解物質の濃度が未知の検査対象液に対して得られた影響度から、その検査対象液に含まれる非電解物質の濃度を求めることができる。
【0044】
このように、上記方法によれば、従来では全く検出することができなかった辛味物質や感度が不足していた甘味物質のような非電解物質を、他の味物質よりも高感度に検出することができる。
【0045】
なお、分子膜17の第1可塑剤(DOPP)を400μlより少なくすると、添加した脂質に対する感度が著しく低下してしまい、3000μl以上では膜化できなくなる。また、第2可塑剤(DOPPのモノエステル体)が1μlより少ない場合や、20μlより多い場合でも、添加した脂質に対する感度が著しく低下することが確認されており、前記したように、高分子材約800mgに対して、第1可塑材が400〜3000μl、第2可塑材が1〜20μlの割合で混合形成した分子膜が、辛味や甘味を呈する非電解物質の検査に最適なものとなる。
【0046】
なお、前記説明では、分子膜17の第2可塑剤がマイナスの電荷をもち、その反対のプラスの極性の電荷をもつ脂質を基準液および検査対象液に添加していたが、逆に第2可塑剤としてプラスの電荷をもつ分子膜を用い、マイナスの電荷をもつ脂質を基準液および検査対象液に添加してもよい。
【0047】
【発明の効果】
以上説明したように、本発明の分子膜は、高分子材と、電荷をもたない第1可塑剤と、電荷をもつ第2可塑剤とを所定の割合、即ち、高分子材約800mgに対して、第1可塑剤が400〜3000μl、第2可塑剤が1〜20μlの割合で混合して形成され、前記第2可塑剤と逆極性の脂質の吸着によって膜電位が変化するように構成されているので、従来の分子膜に比べて基本味物質に対する応答性が極めて低い代わりに、第2可塑剤と逆極性の電荷をもつ脂質の吸着の程度だけを選択的に検出することができ、この脂質の吸着に対する味物質の影響度を検出することができる。
【0048】
また、本発明の非電解物質検出方法は、前記分子膜を検出対象の非電解物質を含まない第1基準液に浸けたときの膜電位と、この第1基準液と同質の液に分子膜と反対の極性の電荷をもつ脂質を添加した第2基準液に浸けてから第1基準液に浸けたときの膜電位との差を基準値として求め、さらに分子膜を第1基準液に浸けたときの膜電位と、前記脂質が添加された検査対象液に分子膜を浸けてから第1基準液に浸けたときの膜電位との差を検査値として求め、基準値と検査値とから検査対象液中の非電解物質を検出している。
【0049】
このため、従来では全く検出できなかった辛味物質や感度が不足していた甘味物質を含む非電解物質を高感度に検出することができる。
【図面の簡単な説明】
【図1】実施形態の検出方法を実施するための検査システムの構成を示す図
【図2】実施形態の検出方法の手順を示すフローチャート
【図3】実際のサンプル液に対する検出結果を示す図
【符号の説明】
11 容器
12 参照電極
13 緩衝層
15 分子膜センサ
16 基材
17 分子膜
18 緩衝層
19 電極
20 電圧検出器
21 A/D変換器
22 演算装置
23 出力装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for detecting a non-electrolytic substance exhibiting pungent taste and sweetness with high sensitivity.
[0002]
[Prior art]
In order to evaluate the taste of foods and drinks, a method using a molecular film made of lipid or the like as a sensor has been proposed.
[0003]
Conventional molecular films used for such purposes include polymer materials such as PVC (polyvinyl chloride), amphiphiles or bitter substances such as lipids (eg, quaternary ammonium salts), plastics, and the like. A material is mixed at a predetermined ratio to form a film, and when immersed in a liquid, the film potential changes according to the substance components in the liquid.
[0004]
Such molecular membrane response characteristics generally do not have a significant selectivity for each taste substance, so in the case of analyzing a taste substance contained in a test object, the component of the molecular film The same test object was measured using a plurality of molecular films having different mixing ratios and substances, and the amount of each taste substance contained in the test object was analyzed from the obtained measurement results.
[0005]
[Problems to be solved by the invention]
However, the conventional inspection using a molecular film has a problem that the detection sensitivity of non-ionized pungent substances and sweet substances is low, and in particular, pungent substances cannot be detected at all.
[0006]
An object of the present invention is to solve this problem and provide a molecular film and a non-electrolyte detection method capable of detecting a non-electrolytic substance with high sensitivity.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a molecular film according to
[0008]
The molecular film of
The first plasticizer is contained in a ratio of 400 to 3000 μl and the second plasticizer is contained in a ratio of 1 to 20 μl with respect to about 800 mg of the polymer material.
[0009]
Further, the non-electrolytic substance detection method of the present invention includes:
A non-electrolytic substance detection method for detecting a non-electrolytic substance in a liquid using the molecular film according to
A first measurement step of measuring the membrane potential by immersing the molecular film in a first reference solution not containing the non-electrolytic substance to be detected;
Immersing the molecular film in a second reference liquid in which a lipid having a charge opposite to that of the molecular film is added to a liquid of the same quality as the first reference liquid;
A second measuring step of immersing the molecular film immersed in the second reference solution in the first reference solution and measuring a membrane potential;
Obtaining a difference between the membrane potential obtained in the first measurement step and the membrane potential obtained in the second measurement step as a reference value;
Washing the molecular film;
A third measurement step of immersing the washed molecular film in the first reference solution and measuring a membrane potential;
Immersing the molecular film in a test solution to which the same substance as the lipid added to the second reference solution is added;
A fourth measurement step of immersing the molecular film immersed in the inspection target liquid in the first reference liquid and measuring a membrane potential;
Obtaining a difference between the membrane potential obtained by the third measurement step and the membrane potential obtained by the fourth measurement step as an inspection value;
And a step of detecting a non-electrolytic substance in the inspection target liquid from the reference value and the inspection value.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a system for performing a non-electrolytic substance detection method according to an embodiment of the present invention.
[0011]
This system includes a container 11 for containing a reference liquid, a test target liquid, and the like, a reference electrode 12, a molecular film sensor 15, and a voltage detector that detects the potential of the molecular film sensor 15 based on the potential of the reference electrode 12. 20, an A / D converter 21 that converts the output of the
[0012]
The reference electrode 12 and the molecular film sensor 15 are used by immersing them in a liquid placed in a container 11, and the surface of the reference electrode 12 is filled with 100 mmol of KCl (potassium chloride) so as not to react with lipids in the liquid. It is covered with a buffer layer 13 fixed with agar, and a lead wire 12a is connected to the upper end.
[0013]
Further, the molecular film sensor 15 is fixed to the surface of a base material 16 such as acrylic with the molecular film 17 exposed on one side, and on the opposite surface, the molecular film sensor 15 is equivalent to the buffer layer 13 of the reference electrode 12. The
[0014]
This molecular film 17 includes a first plasticizer that does not contain lipids or bitter substances and has no charge, and a second plasticizer that has a charge, so as not to respond to various taste substances as in the conventional molecular film. And a polymer material to be a base of the film are mixed at a predetermined ratio.
[0015]
For example, polymer material PVC (polyvinyl chloride), DOPP (dioctylphenyl phosphonate) having no charge as the first plasticizer, and a DOPP monoester having a negative charge as the second plasticizer are mixed. About 800 mg of the product is dissolved in 10 cc of THF, transferred to a flat-bottomed container (for example, a petri dish having a diameter of 85 mm), and kept at about 30 ° C. for 2 hours on a uniform heated plate to volatilize THF A molecular film 17 having a thickness of about 200 μm is obtained.
[0016]
The mixing ratio of the polymer material, the first plasticizer and the second plasticizer is about 400 to 3000 μl for the first plastic material and 1 to 20 μl for the second plastic material with respect to about 800 mg of the polymer material. Basic molecular substances such as salty substances, sour substances, umami substances, sweet substances, bitter substances, astringent substances and pungent substances are not adsorbed to the molecular film 17 thus prepared, and only lipid molecules are adsorbed. It has been confirmed that
[0017]
That is, the molecular film 17 is completely different from the conventional molecular film, has no response to the basic taste substance, and has a response only to the lipid in the liquid.
[0018]
In the actual measurement, the distance between the reference electrode 12 and the molecular film sensor 15 is made constant by a support material (not shown) so that the measurement conditions and the like do not change.
[0019]
The membrane potential of the molecular film 17 based on the potential of the reference electrode 12 is detected by the
[0020]
Next, a procedure of a non-electrolytic substance detection method for detecting non-electrolytic substances such as pungent substances and sweet substances in the liquid to be inspected using the molecular film 17 and the system will be described with reference to the flowchart of FIG. .
[0021]
In this detection method, a non-electrolytic substance to be detected is included, a tasteless first reference liquid corresponding to human saliva, and a liquid of the same quality as the first reference liquid, with a polarity opposite to that of the molecular film 17 ( As described above, the second plasticizer is used with a negative charge) lipid, for example, a positive charge TOMA (trioctylmethylammonium chloride) added at a predetermined concentration (1 ppm). As the first reference solution, for example, KCl (potassium chloride) 30 mM + tartaric acid 0.3 mM solution is used.
[0022]
In addition, lipid TOMA having a charge opposite to that of the molecular film 17 is added to the liquid to be examined in the same concentration as the second reference liquid.
[0023]
First, the reference electrode 12 and the molecular film sensor 15 are immersed in the first reference solution, and the membrane potential Va is measured and stored (S1: first measurement stage).
[0024]
Next, after immersing the reference electrode 12 and the molecular film sensor 15 in the second reference solution for a predetermined time (S2), the reference electrode 12 and the molecular film sensor 15 are returned to the first reference solution, and the membrane potential Vb is measured and stored (S3: second measurement stage). ).
[0025]
Then, the difference ΔV = Vb−Va between the membrane potential Va obtained in the first measurement stage and the membrane potential Vb obtained in the second measurement stage is calculated and stored as a reference value (S4), and then the reference electrode 12 is used. Then, the molecular film sensor 15 is washed (S5).
[0026]
For this cleaning, for example, a cleaning solution of 30 percent ethanol + 100 mM HCl is used.
[0027]
Next, the cleaned reference electrode 12 and the molecular membrane sensor 15 are immersed again in the first reference solution, and the membrane potential Vc is measured and stored (S6: third measurement stage), and then the lipid is added. Immerse in the target liquid for a predetermined time (S7).
[0028]
Then, the reference electrode 12 and the molecular film sensor 15 immersed in the inspection target liquid are returned to the first reference liquid, and the membrane potential Vd is measured and stored (S8: fourth measurement stage).
[0029]
Subsequently, the difference ΔV ′ between the membrane potential Vc obtained in the third measurement stage and the membrane potential Vd obtained in the fourth measurement stage is calculated and stored as an inspection value (S9).
[0030]
Finally, from the reference value ΔV and the test value ΔV ′, the degree of influence P of the substance in the test target liquid on the adsorption of lipid is obtained (S10).
[0031]
In addition, this influence P is calculated | required by the following calculation, for example.
P = (ΔV ′ / ΔV) −1
[0032]
FIG. 3 uses a molecular film 17 formed by mixing about 800 mg of the polymer material PVC with a ratio of 1000 μl of the first plastic material (DOPP) and 10 μl of the second plastic material (DOPP monoester). For the following six types of sample liquids A to F, the above process is performed five times per sample, and the average is obtained.
[0033]
Sample solution A (pungency): KCl (30 mM) + tartaric acid (0.3 mM) + capsaicin (10 μM)
Sample solution B (salty): KCl (300 mM) + tartaric acid (0.3 mM)
Sample solution C (acidity): KCl (30 mM) + tartaric acid (3.0 mM)
Sample solution D (sweet): KCl (30 mM) + tartaric acid (0.3 mM) + sucrose (1 M)
Sample solution E (umami): KCl (30 mM) + tartaric acid (0.3 mM) + MSG (10 mM)
Sample solution F (bitter taste): KCl (30 mM) + tartaric acid (0.3 mM) + quinine hydrochloride (0.1 mM)
Note that these sample liquids are set to a concentration in the middle of the human-sensitive area.
[0034]
As is clear from FIG. 3, the influence degree P for the sample liquids A and D containing the non-electrolytic substance is a negative value, and the absolute value thereof is much larger than the absolute value of the influence degree of the other sample liquids.
[0035]
Therefore, non-electrolytic substances can be detected with high sensitivity by using the above detection method.
[0036]
Here, the negative influence P as in the sample liquids A and D containing pungent or sweet non-electrolytic substances means that the inspection value ΔV ′ is smaller than the reference value ΔV. Indicates that the degree of adsorption of the substance in the liquid when the molecular film 17 is immersed in the liquid to be inspected is less than the degree of adsorption of the substance in the liquid when the molecular film 17 is immersed in the second reference liquid. Yes.
[0037]
As described above, the molecular film 17 does not respond to the basic taste substance itself, but only to lipid (TOMA). Therefore, the decrease in the degree of adsorption described above causes the adsorption of the added TOMA to the molecular film 17. It shows that pungent substances and sweet substances are suppressed.
[0038]
The action of suppressing the adsorption of lipid (TOMA) by the pungent substance occurs when the pungent substance itself binds to the lipid (TOMA) in the liquid. It is presumed that it is caused by covering the surface of the film 17 and preventing adsorption of the pungent substance to the molecular film.
[0039]
The lipid (TOMA) adsorption suppressing action on the molecular film 17 appears in the sample liquid B containing a salty substance, the sample liquid E containing an umami substance, and the sample liquid F containing a bitter substance, but the degree thereof is a non-electrolytic substance. Compared to sample liquids A and D containing
[0040]
In addition, the positive influence P as in the sample liquid C containing a salty substance means that the inspection value ΔV ′ is larger than the reference value ΔV, which means that the molecular film is added to the second reference liquid. This indicates that the degree of adsorption of the substance in the liquid when the molecular film 17 is immersed in the liquid to be inspected is greater than the degree of adsorption of the substance in the liquid when 17 is immersed. That is, the salty substance has an action of increasing the adsorption of lipid to the molecular film 17.
[0041]
In this way, by using the molecular film 17 having no responsiveness to the basic taste substance, it is possible to grasp the degree of influence of the taste substance on the adsorption of the lipid added to the examination target liquid to the molecular film.
[0042]
In addition, when a large negative influence P is obtained when the above-described measurement is performed on a test target liquid whose components are unknown, there is a possibility that the test target liquid contains a large molecular non-electrolytic substance. In contrast, if a positive influence P is obtained, it can be predicted that there is a low possibility that a large molecular nonelectrolytic substance is contained in the liquid to be inspected. It is also expected to contain small molecule non-electrolytes. This is because the non-electrolyte of a small molecule is hydrophobically bonded to the added lipid, and the hydrophobicity of the added lipid is considered to be moderately strong and the adsorption to the molecular film is considered to be strong.
[0043]
In addition, if the above measurement is performed for a plurality of sample liquids having different concentrations of non-electrolytic substances and the relationship between the concentration of non-electrolytic substances and the degree of influence is obtained, the concentration of non-electrolytic substances in the liquid to be inspected is unknown. From the degree of influence obtained in this way, the concentration of the non-electrolytic substance contained in the inspection target liquid can be obtained.
[0044]
Thus, according to the above method, non-electrolytic substances such as pungent substances that could not be detected at all in the past and sweet substances that lack sensitivity are detected with higher sensitivity than other taste substances. be able to.
[0045]
If the first plasticizer (DOPP) of the molecular film 17 is less than 400 μl, the sensitivity to the added lipid is remarkably reduced, and if it is 3000 μl or more, it cannot be formed into a film. Moreover, even when the amount of the second plasticizer (DOPP monoester) is less than 1 μl or more than 20 μl, it has been confirmed that the sensitivity to the added lipid is significantly reduced. A molecular film formed by mixing 400 to 3000 μl of the first plastic material and 1 to 20 μl of the second plastic material for about 800 mg is optimal for the inspection of non-electrolytic substances exhibiting pungent taste and sweetness.
[0046]
In the above description, the second plasticizer of the molecular film 17 has a negative charge, and a lipid having a positive polarity opposite thereto is added to the reference solution and the test solution. A molecular film having a positive charge may be used as a plasticizer, and a lipid having a negative charge may be added to the reference solution and the test solution.
[0047]
【The invention's effect】
As described above, in the molecular film of the present invention, the polymer material, the first plasticizer having no electric charge, and the second plasticizer having electric charge are mixed at a predetermined ratio, that is, about 800 mg of the polymer material. On the other hand, the first plasticizer is formed by mixing at a ratio of 400 to 3000 μl and the second plasticizer at a ratio of 1 to 20 μl, and the membrane potential is changed by adsorption of lipid having a polarity opposite to that of the second plasticizer. Therefore, it is possible to selectively detect only the degree of adsorption of lipids having a charge opposite to that of the second plasticizer, instead of being extremely low in response to basic taste substances compared to conventional molecular membranes. The degree of influence of the taste substance on the adsorption of the lipid can be detected.
[0048]
The non-electrolytic substance detection method of the present invention is characterized in that the molecular film is immersed in a first reference liquid that does not contain the non-electrolytic substance to be detected, and the molecular film is in a liquid that is the same as the first reference liquid. The difference between the membrane potential when immersed in the first reference solution after soaking in the second reference solution to which a lipid having a charge opposite to the polarity is added is obtained as a reference value, and the molecular membrane is immersed in the first reference solution. The difference between the membrane potential when the lipid is added and the membrane potential when the molecular membrane is immersed in the first reference solution after immersing the molecular membrane in the solution to which the lipid is added is obtained as an inspection value. Detects non-electrolytic substances in the test liquid.
[0049]
For this reason, non-electrolytic substances including pungent substances that could not be detected at all in the past and sweet substances whose sensitivity was insufficient can be detected with high sensitivity.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an inspection system for carrying out a detection method of an embodiment. FIG. 2 is a flowchart showing a procedure of the detection method of the embodiment. FIG. 3 is a diagram showing detection results for an actual sample liquid. Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Container 12 Reference electrode 13 Buffer layer 15 Molecular film sensor 16 Base material 17 Molecular film 18
Claims (3)
前記検出対象の非電解物質を含まない第1基準液に前記分子膜を浸けて、膜電位を測定する第1測定段階と、
前記第1基準液と同質の液に前記分子膜と反対の極性の電荷をもつ脂質が添加された第2基準液に前記分子膜を浸ける段階と、
前記第2基準液に浸けた前記分子膜を前記第1基準液に浸けて、膜電位を測定する第2測定段階と、
前記第1測定段階で得られた膜電位と前記第2測定段階で得られた膜電位の差を基準値として求める段階と、
前記分子膜を洗浄する段階と、
前記洗浄した分子膜を前記第1基準液に浸けて、膜電位を測定する第3測定段階と、
前記第2基準液に添加した脂質と同物質が添加された検査対象液に前記分子膜を浸ける段階と、
前記検査対象液に浸けた前記分子膜を前記第1基準液に浸けて、膜電位を測定する第4測定段階と、
前記第3測定段階によって得られた膜電位と前記第4測定段階によって得られた膜電位の差を検査値として求める段階と、
前記基準値と検査値とから、前記検査対象液中の非電解物質を検出する段階とを含むことを特徴とする非電解物質検出方法。A non-electrolytic substance detection method for detecting a non-electrolytic substance in a liquid using the molecular film according to claim 1,
A first measurement step of measuring the membrane potential by immersing the molecular film in a first reference solution not containing the non-electrolytic substance to be detected;
Immersing the molecular film in a second reference liquid in which a lipid having a charge opposite to that of the molecular film is added to a liquid of the same quality as the first reference liquid;
A second measuring step of immersing the molecular film immersed in the second reference solution in the first reference solution and measuring a membrane potential;
Obtaining a difference between the membrane potential obtained in the first measurement step and the membrane potential obtained in the second measurement step as a reference value;
Washing the molecular film;
A third measurement step of immersing the washed molecular film in the first reference solution and measuring a membrane potential;
Immersing the molecular film in a test solution to which the same substance as the lipid added to the second reference solution is added;
A fourth measurement step of immersing the molecular film immersed in the inspection target liquid in the first reference liquid and measuring a membrane potential;
Obtaining a difference between the membrane potential obtained by the third measurement step and the membrane potential obtained by the fourth measurement step as an inspection value;
Detecting a non-electrolytic substance in the inspection target liquid from the reference value and the inspection value.
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