201035544 六、發明說明： 【發明所屬之技術領域】 本發明係關於一種化學感測器，尤指一種用於 檢測尼古丁之安培式化學感測器。 【先前技術】 測量尼古丁的方式有分光光度法、極譜儀法 〇 (polargraphic)、色譜分析法及直接式原子吸收光譜 法（indirect atomic absorption spectrometric)等，然 而上述分析方式皆需耗費時間、且操作方式較為複 雜，樣品皆須進行前處理。近年來普遍開始利用電 化學法進行化學物質檢測，該檢測方法快速、成本 低且無需進行樣品前處理，對於自動在線監控 (automatic on-line monitoring)及即時债測（in situ 0 measurements)有重大的幫助。其中電化學即是探 討化學反應與電荷轉移之間的關係，利用電位調整 電極表面電子能量，使電活性物種與電極發生電荷 轉移。 除此之外，許多研究學者也對於生物感測器 (biosensor)及電化學式生物感測器產生很大的興 趣，開始研究其相關電極材料、修飾物質及其測定 的方法，隨著奈米碳管（carbon nanotube)的發現， 4 201035544 也選擇利用奈米碳管修飾電極的方式來解決電化 學所產生的相關問題。 利用電化學方式量測尼古丁最早是由1981年 Efstathiou等人提出電位式（potentiometric)偵測 方法，利用離子選擇交換電極直接測量出不需經由 純化的菸葉中尼古丁，但因為電極極易受到其他物 質干擾，例如重金屬鋰、鈉、鉀、鈣、鎂、NH4+、 pyridine H+，等，造成測量终草樣品時準確性和再 現性不精準；於1987年Matsue等人提出利用化學 修飾法修飾電極，將0.025 wt%的Nafion溶液利用 微滴揮發（solvent casting)方式修飾在玻璃碳電極 表面上，於室溫下揮發乾燥成薄膜後，將經由尼古 丁化學飾法所修飾的玻碳電極放置在待測溶液 中’普待測溶液中存有（ferrocenyl-methyl) trimethyl- ammonium ion (FA+)物質時，施予一操 作電壓’可得基礎的氧化電流（background oxidation current)與氧化波峰（〇xidati〇I1 peak)，藉由尼古 丁對於FA會產生抑制氧化波峰電流（peak current) 的特性，間接的計算出尼古丁的濃度。 目前最常使用量測尼古丁的方法，包括安培法 與循環伏安法’其中安培法的方式是由Yang et al 等人於2004年所提出，利用尼古丁對膽鹼氧化酶 201035544 (choline oxidase )的抑制化學反應之原理，·間接 測量尼古丁的濃度；另一種測量尼古丁方式為伏 特安培法（voltammetric techniques)，Suffredini 等 人於2005年提出直接測量尼古丁化學物質的方 法，利用摻侧鑽石電極（boron-doped diamond electrode)測量尼古丁在水溶液中的電化學反應， Suffredini利用尼古丁氧化反應產生電流作為製備 〇 化學感測器’其操作電壓為+1 ·2 V vs. Ag/AgCl，所 得的尼古丁偵測極限為0.5 mg/mL，且最佳的PH值 為 8.0。 然而隨著奈米材料的發展，且奈米碳管具有高 的化學穩定性、高表面積、良好的電傳導性質、機 械性質管狀的結構等特性，逐漸將奈米碳管修 飾電極的原理應用至許多技術中。且因為奈米尺寸 〇 的氧化㈣粒表面積大、良㈣雜践在電化學 及電刀析領域備$關注，藉由該材料作為電極修飾 劑的化于感，則器’用於尼古丁濃度的偵測在國内外 仍未見報導。右 为繼於此，本發明期望利用奈米碳管 的特性提出一蘇&# 種能於低工作電壓直接量測尼古丁 的 ' 在有效時間内，達到高靈敏度以及較低 的偵測柽限。 6 201035544 【發明内容】 本發明的目的之一是提供一種高靈敏度的化 子感則器’其中該化學感測器可用來檢測尼古丁的 濃度。 本發明的目的之二是提供多層壁奈米碳管修 飾玻璃電極的製備方法，該多層壁奈米碳管 内含有 三氧化二鋁包覆二氧化矽奈米顆粒複合物之薄膜。 0 本發明提供一種化學感測器，包括玻璃碳 電極，其特殊處在於該玻璃碳電極表面塗覆有 多層壁奈米碳管，該多層壁奈米碳管具有多孔 性結構，可增加其表面積及導電性，且經過修 飾之玻璃碳電極表面可增加電子傳遞速度及 電催化氧化還原的效果。 上述化學感測器的製備方法，係將多層壁 》 奈米碳管和含具有多孔性結構的奈米顆粒混合均 勻，得到多層壁奈米碳管溶液，將該溶液修飾到 玻璃碳電極表面，即得到所需之感測器，可用於偵 測尼古丁之濃度。 上述之化學感測器，可在0 4V至〇 85v 之低工作電壓下直接偵測尼古丁濃度’且因在 玻璃碳電極表面上修飾多層壁奈米碳管，可藉 此防止電極毒化反應的產生。 7 201035544 上述之化學感測器，以多層壁奈米碳管· 二氧化二鋁包覆二氧化矽奈米顆粒複合物修 飾於玻璃碳電極表面，具有高靈敏度及低偵測 極限’分別可達126.247 μΑ/mM及1.42 μΜ。 本發明另提供一種玻璃碳電極，該玻璃碳電 極以多層壁奈米碳管_三氧化二銘包覆二敦化 矽奈米顆粒複合物修飾於表面，可用於尼古丁 及各種化學物質化學感測器的偵測。 上述之玻璃碳電極，藉由多層壁奈米碳管 可與多孔性奈米顆粒結合，以增加其表面積及 導電性，並防止電極毒化反應的產生。 本發明所提供之化學感測器，可以低成本及短 時間内進行尼古丁濃度的檢測，其中所使用的電極 是經過多層壁奈米碳管-三氧化二鋁包覆二氧化矽 奈米顆粒複合物修飾玻璃碳電極，主要是藉由多層 壁奈米碳管可使電極具抗毒化及提供高穩定性，該 電極的製備方法簡單且無須樣品前處理，可以當作 種良好的尼古丁化學感測器的偵測。經過修飾的 玻璃碳電極和未經過任何薄膜修飾之玻璃碳電極 相比，多層壁奈米碳管_三氧化二鋁包覆二氧化矽奈 米顆粒複合物修飾玻璃碳電極較玻璃碳電極，可有 較低的應答時間、高靈敏度以及較低的偵測極限。 8 201035544 經過多層壁奈米碳管修飾的玻璃碳電極電流 比未添加多層壁奈米碳管修飾玻璃碳電極的穩定 性更高、訊號再現性高、線性範圍增加，以上敘述 皆顯不多層壁奈米碳管非常適合做為催化尼古 丁，製備尼古丁化學感測器的材料。 【實施方式】 0 本發明的目的係建立在一種感測器上進行尼 古丁濃度量測，其中電化學電極係藉由奈米顆粒複 合物修飾玻璃碳電極所形成之奈米碳管，該奈米碳 S具有间化學穩定性、高表面積、良好的電傳導性 質、機械性質以及管狀的結構等特性，可作為電化 學安培法使用之工作電極，且此製備方法成本低 廉，操作簡單、快速且樣品無需前處理。 》 本發明之其他特色及優點將於下列實施範例 中被進一步舉例與說明，而該實施範例僅作為辅助 說明，並非用於限制本發明之範圍。 實施例一：製備多層壁奈米碳管_三氧化二鋁包覆 二氧化石夕奈米顆粒修飾玻璃碳電極 1.玻璃碳電極之前處理 首先將玻璃碳電極以去離子水沖洗表面，用拭 9 201035544 〜鏡紙擦乾，以0.3 μιη的氧化鋁粉進行拋光’再以乾 淨的去離子水清洗之，接著使用顆粒較細的〇.〇5 μιη 的氧化鋁粉進行拋光，並以去離子水清洗及拭淨 後，用丙酮沖洗電極表面數次，最後再以乾淨的去 離子水在超音波下震盪兩分鐘，以拭鏡紙擦乾備用 即可，如此處理後的電極以確保電極表面無任何物 質殘留。 ❹ 2.工作電極的製備 將20 mg/mL多層壁奈米碳管加入於1 wt. %， pH值2的三氧化二鋁包覆二氧化矽奈米顆粒水溶 液中，經超音波震盪後，可得到一黑色均勻懸浮液； 再將玻璃碳電極浸入多層壁奈米碳管-三氧化二鋁 包覆二氧化矽奈米顆粒水溶液中60分鐘，使得奈米 顆粒能吸附在玻璃碳電極表面上，最後利用去離子 〇 水沖洗電極周圍的絕緣樹脂數次，在室溫下自然乾 燥30分鐘，即可完成多層壁奈米碳管-三氧化二鋁 包覆二氧化矽奈米顆粒修飾玻璃碳電極的製備。 3.偵測條件與方式 將製備好的工作電極，藉由場發射式掃描式電 子顯微鏡(Field emission-scanning electron microscope, FE-SEM)觀察表面形貌，在加速電壓為 3KV，放大倍數為30,000倍的條件下，觀察多層壁 201035544 奈米碳管·三氧化4包覆二氧切奈来顆粒複合 物薄膜的表面形貌。 4.結果 圖1(a)與圖1(b)分別為未經過自组裝的方式修 飾於玻璃碳電極之FESEM表面形貌圖與玻璃碳電 極浸入pH2之1 wt%三氧化二铭包覆二氧化石夕奈米 顆粒水溶液60分鐘後，於室溫下乾燥之1^兕馗表 面形貌圖。比較圖1⑷與圖1(b)，可以看出圖丨⑻ 表面上二氧化二鋁包覆二氧化矽奈米顆粒均句的覆 蓋於玻璃碳電極的表面。 另外，將玻璃碳電極浸入pH2之i wt%多層壁 奈米碳管-二氧化二鋁包覆二氧化矽奈来顆粒之水 溶液中60分鐘’得到圖1(c),由圖中可以清楚的看 到多層壁奈米碳管與三氧化二鋁包覆二氧化矽奈米 顆粒複合物均勻的修饰於玻璃碳電極上。 經由FESEM之結果顯示，本發明成功的將多 層壁奈米碳管-二氧化二鋁包覆二氧化梦奈米顆粒 複合物以自組裝的方式修飾於玻璃碳電極上；且發 現多層壁奈米碳管-三氧化二鋁包覆二氧化矽奈米 顆粒複合物為多孔性的結構，有助於電化學實驗中 多層壁奈米碳管和溶液的電子交換，並希望藉多層 壁奈米碳管優異之導電性質，幫助電子快速傳遞， 11 201035544 產生電權化之效果，而且多層碳壁管的添加會增加 其比表面積進而造成電流訊號增加。 實施例二：偵測尼古丁的電化學行為 為了製作化學感測器，我們須偵測奈米碳管對 於尼古丁化學物質是否能進行催化氧化反應，並從 中了解經修飾後電極對於尼古丁的催化活性與當 〇 其反應時對於電極表面所造成的影響，及評估測量 修飾電極偵測尼古丁所使用的操作電位。 1. 工作電極系統 a. 工作電極（working electrode，WE) ··直徑 3 mm 的玻璃碳電極（Glassy Carbon Electrode， GCE) (CHI 104, CH Instruments, Inc.) b. 參考電極(reference electrode，RE) ·· ^ Ag/AgCl(3M KC1) (Metrohm) c. 輔助電極（counter electrode，CE):白金電極 (Metrohm) d. 電化學測試槽：裝盛待測溶液，可裝盛容量 為 10-90mL (Metrohm) 2. 偵測條件與方式 本實施例欲了解多層壁奈米碳管-三氧化二鋁 包覆二氧化矽複合物薄膜修飾玻璃碳電極對於尼 12 201035544 古丁的氧化能力’將翻電極、玻璃碳電極、三氧化 二銘包覆：氧切奈米顆粒複合物修飾之玻璃碳 電極及多層壁奈米碳管·三氧化二銘包覆二氧化石夕 複合物薄膜修飾玻璃碳電極等四種電極’在〇至 0.85 V操作電位範圍下，將四種電極放置於m PBS(PH8.G)中’則猶環伏安法以5GmV/s的掃 描速率對尼古了崎彳貞測掃描。 3.結果 圖2(a)與（b)分別為銷電極於〇1MpBS(pH8) =入10 μΜ尼古丁與未加人尼古丁掃描之循環伏 文圖（c)與⑷为別為玻璃碳電極於〇丄mpbs (ρΗ8) :入10 μΜ尼古丁與未加入尼古丁掃描之循環伏 安圖’·⑷與(f)分別為三氧化二鋁包覆二氧化矽奈米 > 顆粒複合物修飾之玻璃碳電極於0.1 M PBS (pH8) 加入ίο μΜ尼古丁與未加人尼古丁掃描之循環伏 安圖’（g)與(h)分別為多層壁奈米碳管-三氧化二銘 包覆氧化梦奈米顆粒複合物修飾之玻璃碳電極 於0.1 M PBS (pH8)加人ι〇μΜ尼古丁與未加入尼 古丁掃描之循環伏安圖。 由圖2(g)上可以觀察到多層壁奈米碳管_三氧 化一鋁包覆二氧化矽奈米顆粒複合物修飾玻璃碳 電極對於10 μΜ尼古丁的循環伏安曲線，在〇4v 13 201035544 時有明顯的氧化電流I生；由圖2(e)上可清楚的觀 察到玻璃碳電極料1〇 —《古丁的循環伏安曲 線，在0.5 V才有明顯的氧化電流產生；且多層壁 奈米碳管-二氧化二鋁包覆二氧化矽奈米顆粒複合 物修飾玻璃碳電極的背景電流明顯得高於其它電 極，這是由於多層壁奈米碳管的高表面積和多孔性 結構所致。 由本實驗中發現經由多層壁奈米碳管_三氧化 二鋁包覆二氧化矽奈米顆粒複合物修飾的玻璃碳 電極，會使得尼古丁陽極波鋒電位往負向電位平移 至0.65 Vvs. Ag/AgC卜使得整體操作電壓下降，並 且使電流訊號增加。故由此可得知在經由多層壁奈 求碳管-三氧化二鋁包覆二氧化矽奈米顆粒複合物 修飾玻璃碳電極，可使尼古丁在電極表面加速電子 傳遞反應，因此只需在較低電位下即對尼古丁產生 氧化反應，是具有良好的電催化活性。 另外’由圖3顯示，利用多層壁奈米碳管三 氧化二銘包覆二氧化梦奈米顆粒複合物修飾的玻 璃碳電極’於0.1 MPBS (pH8)添加尼古丁和未添 加尼古丁之線性掃描伏安圖。隨著尼古丁濃度的增 加，其中氧化電流亦會隨之增加，且氧化電位可在 約0.65 V vs· Ag/AgCl下被觀察到；且由插圖中可以 201035544 看出尼古丁濃度在5 μΜ至45 μΜ之間對於氧化電 流為成正比關係，因此我們可以清楚知道多層壁奈 米碳管能夠有效率的從電極表面轉移電子到溶液 中。 實施例三：偵測尼古丁濃度 在經循環伏安圖以及線性掃描伏安圖譜中選 出最適操作電位後，將玻璃碳電極、三氧化二鋁包 覆一氧化梦奈米顆粒複合物修飾之玻璃碳電極、多 層壁奈米碳管-三氧化二鋁包覆二氧化矽奈米顆粒 複合物修飾玻璃碳電極等三種電極，利用安培法進 行尼古丁濃度測試。 1. 偵測條件與方式 在0.7 V(vs Ag/AgCl)的操作電壓，分別將玻璃 碳電極、二氧化二鋁包覆二氧化矽奈米顆粒複合物 修飾之玻璃碳電極、多層壁奈米碳管-三氧化二鋁包 覆一氧化梦奈米顆粒複合物修飾玻璃碳電極等= 種電極，置於0.1MPBS(PH8.0)的溶液中，每兩分 鐘添加不同濃度的尼古丁，藉由電流訊號計算出尼 古丁的濃度。 2. 結果 由圖4得知，圖4 (a)、圖4 (b)、圖4 (c)分別 15 201035544 在玻璃碳電極、三氧化上鋁包覆二氧化矽奈米顆粒 複合物修飾之玻璃破電極、多層壁奈米碳管-三氧化 二鋁包覆二氧化矽奈米顆粒複合物修飾之玻璃碳 電極下，加入不同濃度尼古丁所得之安培圖。由圖 4可清楚得知，當玻璃碳電極表面經由多層壁奈米 碳管修飾後’電流訊號明顯的高於其他兩種電極材 料，且經由多層壁奈米破管修飾的玻璃碳電極，其 電流訊號增加後都能保持一穩定的水平狀態。另 外’可以藉由此實驗計算出，玻璃碳電極、三氧化 二銘包覆二氧化矽奈米顆粒複合物修飾之玻璃碳 電極與多層壁奈米碳管-三氧化二鋁包覆二氧化石夕 奈米顆粒複合物修飾之玻璃碳電極的靈敏度分別 為0.679、0.663及126.247 μΑ/mM，偵測極限分別 為1.57、2.98、及1.42 μΜ，因此可以得知’當加 入多層壁奈米碳管時，相較於玻璃碳電極其靈敏度 可提高190倍左右，可以偵測到較低的濃度。而多 層壁奈米碳管-三氧化二鋁包覆二氧化矽奈米顆粒 複合物修飾玻璃碳電極之應答時間小於7秒，而其 他兩者電極則小於12秒，這也證明了多層壁奈米 碳管的確可增加電極比表面積，相對減少偵測尼古 丁之應答時間。 圖4之插圖為玻璃碳電極、三氧化二鋁包覆二 16 201035544 氧化砍奈米 '顆粒複合物修飾之玻璃碳電極、·多層壁 奈米碳爹-三氧化二鋁包覆二氧化矽奈米顆粒複合 物修飾玻璃碳電極偵測不同濃度尼古丁之校正曲 線。 綜合以上所有結果，我們可以了解多層壁奈米 碳管-二氧化一紹包覆一氧化秒奈米顆粒複合物修 飾玻璃碳電極對於催化尼古丁的反應的確是有迅 〇 速增加電流訊號的能力，靈敏度高且可偵測到更低 的濃度，應答時間小於7秒，是一種能有效偵測尼 古丁之化學感測器。 實施例四：電極毒化反應 在電化學實驗中，有時會因為工作電壓的不合 適，而造成訊號衰退的現像，故我們將針對經由奈 米顆粒複合物修飾之玻璃碳電極進行試驗，以證明 不會產生過大的操作電壓而致電極毒化反應。 1·偵測條件與方式 在0·7 V操作電壓下’分別將玻璃碳電極、多 層壁奈米碳管•三氧化二鋁包覆二氧化矽奈米顆粒 修飾玻璃碳電極置入含有〇 ] M pBS (pH 8 〇)的攪 拌溶液中，持續穩定反應1〇〇〇秒後，加入1〇 μΜ 的尼古丁進行電化學反應並持續監測電流訊號。 201035544 2 ·結果 . 由圖5中顯示，隨著尼古丁的加入而產生電 流，圖5 (a)、圖5 (b)分別為玻璃碳電極、多層壁 不米妷管-二氧化二鋁包覆二氧化矽奈米顆粒修飾 之玻璃碳電極下偵測尼古丁之安培反應紀錄圖，可 得知有添加多層壁奈米碳管所產生的電流較無添 〇加的只有單純玻璃碳電極的電流訊號為更增大，此 外，由圖5中我們也可以看出多層壁奈米碳管三氧 化二鋁包覆二氧化矽奈米顆粒修飾玻璃碳電極測 量尼古丁，經1000秒之後訊號衰退105%，玻璃碳 電極則衰退28.6%，由此可以顯示出多層壁奈米碳 管-三氧化二鋁包覆二氧化矽奈米顆粒修飾玻璃碳 電極有顯著的對於尼古丁氧化反應具抗污染毒化 及操作穩定。 ) 以上的結果可以顯示出奈米複合薄膜修飾電 極相當適合用作對尼古丁化學感測器，也證明操作 電壓不會產生過大而致電極毒化反應。 雖然别述的描述及圖不已揭不本創作之較佳 實施例，必須瞭解到各種增添、修改和取代可能使 用於本創作較佳實施例，而不會脫離如所附申請專 利範圍所界定的本創作原理之精神及範圍。熟悉該 201035544 技藝者將可體會本創作可能使用於报多形式、結構 和材料的修改。因此，本文於此所揭示的實施例於 所有觀點，應被視為用以說明本創作，而非用以限 制本創作。本創作之範圍應由後附申請專利範圍所 界定’並涵蓋其合法均等物’並不限於先前的描述。 201035544 【圖式簡單說明】 圖1顯示不同電極之FESEM表面形貌圖，其 中圖1 (a)係為未經修飾之玻璃碳電極之FESEM表 面形貌圖；圖1(b)係三氧化二鋁包覆二氧化矽奈米 顆粒修飾玻璃碳電極之FESEM表面形貌圖；圖1 (c) 係多層壁奈米碳管-三氧化二鋁包覆二氧化矽奈米 〇 顆粒修飾玻璃碳電極之FESEM表面形貌圖。 圖2顯示不同電極之循環伏安圖，其中圖2 (a) 與（b)係為鉑電極於pH 8的0.1 M PBS溶液中加入 10 μΜ尼古丁與未加入尼古丁掃描之循環伏安圖； (c)與（d)係為玻璃碳電極於pH 8的0.1 M PBS溶液 中加入10 μΜ尼古丁與未加入尼古丁掃描之循環伏 安圖；（e)與（f)係為三氧化二鋁包覆二氧化矽奈米顆 粒複合物修飾之玻璃碳電極於pH 8的0.1 M PBS溶 液中加入ΙΟμΜ尼古丁與未加入尼古丁掃描之循環 伏安圖；（g)與（h)係為多層壁奈米碳管·三氧化二鋁 包覆二氧化矽奈米顆粒複合物修飾之玻璃碳電極於 pH 8的0.1 M PBS溶液中加入10 μΜ尼古丁與未加 入尼古丁掃描之循環伏安圖。 圖3係為本發明多層壁奈米碳管-三氧化二鋁 包覆二氧化矽奈米顆粒複合物修飾之玻璃碳電極於 201035544 ' pH 8的0.1 M PBS溶液中，分別加入不同濃度的尼 古丁之線性掃描伏安圖，其中（a)未加入尼古丁；（b) 加入 5 μΜ ; (c)加入 10 μΜ ; (d)加入 15 μΜ ; (e)加 入25 μΜ ; (f)加入35 μΜ ; (g)加入45 μΜ之線性掃 描伏安圖。 圖4(a)未經修飾之玻璃碳電極；（b)三氧化二 鋁包覆二氧化矽奈米顆粒修飾玻璃碳電極；（c)多層 〇 壁奈米碳管-三氧化二鋁包覆二氧化矽奈米顆粒修 飾玻璃碳電極於pH 8的0.1 M PBS溶液中，偵測尼 古丁不同濃度之安培圖。 圖5(a)未經修飾之玻璃碳電極；（b)多層壁奈 米碳管-三氧化二鋁包覆二氧化矽奈米顆粒修飾玻 璃碳電極，於pH 8的0.1 M PBS溶液中，在0.7 V vs. Ag/AgCl的操作電壓下加入10 μΜ尼古丁反應1000 〇 秒之安培反應記錄圖。 【主要元件符號說明】 21201035544 VI. Description of the Invention: [Technical Field] The present invention relates to a chemical sensor, and more particularly to an amperometric chemical sensor for detecting nicotine. [Prior Art] The methods for measuring nicotine include spectrophotometry, polarography, chromatographic analysis, and direct atomic absorption spectrometry. However, the above analysis methods take time and The operation method is complicated, and the samples must be pretreated. In recent years, electrochemical methods have been widely used for chemical substance detection. The detection method is fast, low in cost and does not require sample preparation. It is significant for automatic on-line monitoring and in situ 0 measurements. s help. Electrochemistry is the relationship between chemical reaction and charge transfer. The potential is used to adjust the electron energy on the surface of the electrode to cause charge transfer between the electroactive species and the electrode. In addition, many researchers have also developed great interest in biosensors and electrochemical biosensors, and began to study their related electrode materials, modifying substances and their determination methods, along with nanocarbon. The discovery of carbon nanotubes, 4 201035544 also chose to use nanocarbon tubes to modify the electrodes to solve the problems associated with electrochemistry. The electrochemical measurement of nicotine was first proposed by Efstathiou et al. in 1981. The potentiometric detection method was used to directly measure nicotine in tobacco leaves without purification, but because the electrodes were highly susceptible to other substances. Interference, such as heavy metals such as lithium, sodium, potassium, calcium, magnesium, NH4+, pyridine H+, etc., causes inaccuracies in the accuracy and reproducibility of the measurement of the final grass sample; in 1987 Matsue et al. proposed to modify the electrode by chemical modification. The 0.025 wt% Nafion solution was modified on the surface of the glassy carbon electrode by solvent casting, and after evaporation to a film at room temperature, the glassy carbon electrode modified by the nicotine chemical decoration method was placed in the solution to be tested. When a (ferrocenyl-methyl) trimethyl- ammonium ion (FA+) substance is present in the solution to be tested, an operating voltage 'applied to the background oxidation current and the oxidation peak (〇xidati〇I1 peak) ), indirect calculation of the characteristic of suppressing the oxidation peak current by the nicotine for FA The concentration of nicotine. At present, the most commonly used methods for measuring nicotine include amperometric and cyclic voltammetry. The method of amperometric method is proposed by Yang et al et al. in 2004, using nicotine for choline oxidase 201035544 (choline oxidase). The principle of inhibiting chemical reactions, indirectly measuring the concentration of nicotine; another method of measuring nicotine is voltammetric techniques, Suffredini et al. proposed a method for direct measurement of nicotine chemicals in 2005, using a side-doped diamond electrode (boron- Doped diamond electrode) measures the electrochemical reaction of nicotine in aqueous solution. Suffredini uses the nicotine oxidation reaction to generate electric current as a preparation chemical sensor. The operating voltage is +1 · 2 V vs. Ag/AgCl, and the resulting nicotine detection limit. It is 0.5 mg/mL and the optimum pH is 8.0. However, with the development of nanomaterials, and the carbon nanotubes have high chemical stability, high surface area, good electrical conductivity, mechanical properties, tubular structure, etc., gradually apply the principle of carbon nanotube modified electrode to Many technologies. And because of the nanometer size 氧化 oxidation (four) grain surface area, good (four) miscellaneous in the field of electrochemistry and electrospinning, pay attention to the use of this material as an electrode modifier, then the device 'for nicotine concentration The detection has not been reported at home and abroad. Right now, the present invention contemplates utilizing the characteristics of the carbon nanotubes to propose a Su &# capable of directly measuring nicotine at low operating voltages, achieving high sensitivity and low detection limits in an effective time . 6 201035544 SUMMARY OF THE INVENTION One object of the present invention is to provide a highly sensitive chemisensor, wherein the chemical sensor can be used to detect the concentration of nicotine. Another object of the present invention is to provide a method for preparing a multilayered wall carbon nanotube-modified glass electrode comprising a film of a cuprous oxide-coated cerium oxide nanoparticle composite. The present invention provides a chemical sensor comprising a glassy carbon electrode, in particular, the surface of the glassy carbon electrode is coated with a multi-layered wall carbon nanotube having a porous structure to increase the surface area thereof. And the conductivity, and the surface of the modified glassy carbon electrode can increase the electron transport speed and the effect of electrocatalytic redox. The above chemical sensor is prepared by mixing a multi-walled carbon nanotube and a nanoparticle having a porous structure to obtain a multi-layered wall carbon nanotube solution, and modifying the solution to the surface of the glassy carbon electrode. The desired sensor is obtained for detecting the concentration of nicotine. The above-mentioned chemical sensor can directly detect the nicotine concentration at a low operating voltage of 0 4V to 〇85v and can prevent the generation of the poisoning reaction by modifying the multi-walled carbon nanotube on the surface of the glassy carbon electrode. . 7 201035544 The above-mentioned chemical sensor is modified on the surface of glassy carbon electrode by multi-layered wall carbon nanotubes and aluminum oxide coated cerium oxide nanoparticle composite, which has high sensitivity and low detection limit. 126.247 μΑ/mM and 1.42 μΜ. The invention further provides a glassy carbon electrode which is modified on the surface by a multi-layered wall carbon nanotube_three-oxide two-layer coating, and can be used for nicotine and various chemical chemical sensors. Detection. The above glassy carbon electrode can be combined with porous nanoparticle by a multi-walled carbon nanotube to increase its surface area and conductivity, and to prevent the formation of an electrode poisoning reaction. The chemical sensor provided by the invention can detect the concentration of nicotine at low cost and in a short time, wherein the electrode used is a composite of a plurality of layers of carbon nanotubes-aluminum oxide coated with cerium oxide nano particles. The modified glassy carbon electrode is mainly used to make the electrode anti-toxic and provide high stability by the multi-layered wall carbon nanotube. The preparation method of the electrode is simple and does not require sample preparation, and can be used as a good nicotine chemical sensing. Detection. The modified glassy carbon electrode is compared with the glassy carbon electrode without any film modification, and the multi-walled carbon nanotube-alumina-coated cerium oxide nanoparticle composite modified glassy carbon electrode is more than the glassy carbon electrode. Low response time, high sensitivity and low detection limits. 8 201035544 The glassy carbon electrode current modified by multi-walled carbon nanotubes has higher stability, higher signal reproducibility and increased linear range than the multi-walled nanocarbon tube modified glassy carbon electrode. Nano carbon tubes are very suitable as materials for the preparation of nicotine chemical sensors for catalyzing nicotine. [Embodiment] The purpose of the present invention is to establish a nicotine concentration measurement on a sensor, wherein the electrochemical electrode is a carbon nanotube formed by modifying a glassy carbon electrode by a nanoparticle composite, the nanocarbon S has the characteristics of chemical stability, high surface area, good electrical conductivity, mechanical properties and tubular structure. It can be used as a working electrode for electrochemical amperometric method, and the preparation method is low in cost, simple in operation, fast and no need for samples. Pre-processing. The other features and advantages of the present invention are further exemplified and described in the following examples, which are intended to be illustrative only and not to limit the scope of the invention. Example 1: Preparation of multi-layered wall carbon nanotubes_Al2O3 coated dioxide SiO2 granules modified glassy carbon electrode 1. Glass carbon electrode before treatment First, the glassy carbon electrode was rinsed with deionized water, and wiped 9 201035544 ~ Mirror paper dried, polished with 0.3 μηη alumina powder' and then cleaned with clean deionized water, then polished with finely divided 〇.〇5 μιη alumina powder and deionized After washing and wiping the water, rinse the surface of the electrode with acetone several times, and then shake it with clean deionized water for 2 minutes under ultrasonic waves. Dry it with a mirror paper and leave it as needed. The electrode thus treated ensures the surface of the electrode. No substance remains. ❹ 2. Preparation of working electrode 20 mg / mL multi-walled carbon nanotubes were added to 1 wt. %, pH 2 of aluminum oxide coated cerium oxide nanoparticle aqueous solution, after ultrasonic shock, A black uniform suspension can be obtained; the glassy carbon electrode is immersed in the multi-walled carbon nanotube-alumina coated cerium oxide nanoparticle aqueous solution for 60 minutes, so that the nanoparticle can be adsorbed on the surface of the glassy carbon electrode. Finally, the insulating resin around the electrode is rinsed several times with deionized water, and dried naturally at room temperature for 30 minutes to complete the multi-walled carbon nanotube-alumina coated cerium oxide nanoparticle modified glassy carbon. Preparation of the electrode. 3. Detection conditions and methods The prepared working electrode was observed by a field emission-scanning electron microscope (FE-SEM) with an acceleration voltage of 3 kV and a magnification of 30,000. Under the conditions of multiple times, the surface morphology of the multi-wall 201035544 nano-carbon tube·three-oxide-coated dioxetine particle composite film was observed. 4. Results Fig. 1(a) and Fig. 1(b) show the FESEM surface topography modified with glass-carbon electrode without self-assembly and 1 wt% oxidized by glassy carbon electrode immersed in pH2. After 60 minutes of the aqueous solution of the cerium oxide cerium nanoparticles, the surface topography of the dried 于 于 。 。 Comparing Fig. 1 (4) with Fig. 1 (b), it can be seen that the surface of the glassy carbon electrode is coated on the surface of the glassy carbon electrode on the surface of the layer (8). In addition, the glass carbon electrode is immersed in an aqueous solution of i wt% multi-walled nanotubes of carbon dioxide-alumina coated with cerium oxide nanoparticle for 60 minutes to obtain Figure 1 (c), which can be clearly seen from the figure. It was found that the multi-layered wall carbon nanotubes and the alumina-coated cerium oxide nanoparticle composite were uniformly modified on the glassy carbon electrode. The results of FESEM show that the present invention successfully modified the multi-layered wall carbon nanotube-alumina coated dioxide monoxide particle composite on the glassy carbon electrode in a self-assembled manner; Carbon tube-alumina coated cerium oxide nanoparticle composite is a porous structure, which facilitates the electron exchange of multi-walled carbon nanotubes and solution in electrochemical experiments, and hopes to borrow multi-wall nanocarbon The excellent electrical conductivity of the tube helps the electrons to transfer quickly. 11 201035544 The effect of electrification is achieved, and the addition of multi-layer carbon wall tubes increases the specific surface area and thus increases the current signal. Example 2: Detecting the electrochemical behavior of nicotine In order to make a chemical sensor, we must detect whether the carbon nanotubes can catalyze the oxidation of nicotine chemicals, and learn about the catalytic activity of the modified electrode for nicotine. The effect on the electrode surface when 〇 is reacted, and the measurement of the operating potential used by the modified electrode to detect nicotine is evaluated. 1. Working electrode system a. Working electrode (WE) · Glass-carbon electrode with a diameter of 3 mm (Glassy Carbon Electrode, GCE) (CHI 104, CH Instruments, Inc.) b. Reference electrode (RE ·· ^ Ag/AgCl(3M KC1) (Metrohm) c. Auxiliary electrode (CE): Platinum electrode (Metrohm) d. Electrochemical test tank: loaded with the solution to be tested, can hold a capacity of 10- 90mL (Metrohm) 2. Detection conditions and methods This embodiment is to understand the multi-walled carbon nanotube-alumina coated cerium oxide composite film modified glass carbon electrode for Ni 12 201035544 Gudin's oxidation ability 'will turn Electrode, glassy carbon electrode, bismuth oxide coating: glassy carbon electrode modified by oxygen chevron granule composite and multi-layered wall carbon nanotubes · oxidized bismuth oxide coated quartz dioxide composite film modified glass carbon electrode Wait for the four electrodes to place the four electrodes in m PBS (PH8.G) at the operating potential range of 0.85 V. The helium ring voltammetry is rugged to the Nico at a scan rate of 5 GmV/s. Test scan. 3. Results Figure 2 (a) and (b) respectively for the pin electrode at 〇1MpBS (pH8) = 10 μΜ nicotine and un-human nicotine scan cyclic voltagram (c) and (4) for the glassy carbon electrode 〇丄mpbs (ρΗ8): Cyclic voltammograms of 10 μΜ nicotine and no nicotine scans········································· Electrode in 0.1 M PBS (pH 8) was added to ίο μΜ nicotine and cyclic voltammograms without scanning with nicotine '(g) and (h) respectively for multi-walled nanotubes - Oxidation of oxidized Mengnai The particle composite modified glassy carbon electrode was added to 0.1 M PBS (pH 8) with human 〇μ〇 nicotine and a cyclic voltammogram without the addition of nicotine scan. From Figure 2(g), the cyclic voltammetry curve of 10 μΜ nicotine can be observed in a multi-walled nanotubes-aluminum-aluminum-coated aluminum dioxide-coated nanoparticle composite modified glassy carbon electrode at 〇4v 13 201035544 When there is a significant oxidation current I; it can be clearly seen from Fig. 2(e) that the glassy carbon electrode material 1〇-"the cyclic voltammetry curve of the gudin, the obvious oxidation current is generated at 0.5 V; and the multi-layer wall The background current of the modified carbon nanotube electrode modified by the carbon nanotube-alumina coated cerium oxide nanoparticle composite is significantly higher than that of other electrodes due to the high surface area and porous structure of the multilayered wall carbon nanotube. To. From this experiment, it was found that the glassy carbon electrode modified by the multi-walled carbon nanotube-alumina-coated cerium oxide nanoparticle composite will shift the nicotine anode wave front potential to the negative potential to 0.65 Vvs. Ag/ AgC causes the overall operating voltage to drop and the current signal to increase. Therefore, it can be known that the modification of the glassy carbon electrode by the carbon nanotube-alumina coated cerium oxide nanoparticle composite through the multilayer wall can accelerate the electron transport reaction of the nicotine on the electrode surface, so At low potential, it produces an oxidation reaction to nicotine and has good electrocatalytic activity. In addition, as shown in Fig. 3, the glassy carbon electrode modified with the double-walled nanotube carbon nanotubes was coated with the oxidized Monaco granule complex, and the linear scan volts of nicotine and nicotine were added in 0.1 MPBS (pH 8). Antu. As the concentration of nicotine increases, the oxidation current also increases, and the oxidation potential can be observed at about 0.65 V vs· Ag/AgCl; and the concentration of nicotine in the illustration can be seen from 201035544 at 5 μΜ to 45 μΜ. There is a proportional relationship between the oxidation currents, so we can clearly know that multi-walled carbon nanotubes can efficiently transfer electrons from the electrode surface to the solution. Example 3: Detecting the concentration of nicotine After selecting the optimum operating potential in the cyclic voltammogram and the linear sweep voltamogram, the glassy carbon electrode and the aluminum oxide coated with the oxidized monocyte granule complex modified glassy carbon Electrode, multi-walled carbon nanotube-alumina coated with cerium oxide nanoparticle composite modified glass carbon electrode and other three electrodes, using the amperometric method for nicotine concentration test. 1. Detection conditions and methods at 0.7 V (vs Ag/AgCl) operating voltage, glass carbon electrode, alumina coated with cerium oxide nanoparticle composite modified glass carbon electrode, multi-layered wall nano Carbon tube-aluminum oxide coated with monoxide granule composite modified glass carbon electrode, etc. = electrode, placed in 0.1M PBS (pH 8.0) solution, adding different concentrations of nicotine every two minutes, by The current signal calculates the concentration of nicotine. 2. The results are shown in Fig. 4. Fig. 4 (a), Fig. 4 (b), and Fig. 4 (c) respectively 15 201035544 modified with a glassy carbon electrode and aluminum oxide coated with cerium oxide nanoparticle composite An amperometric diagram obtained by adding different concentrations of nicotine under a glassy carbon electrode modified by a glass-breaking electrode, a multi-layered wall carbon nanotube-aluminum oxide-coated cerium oxide nanoparticle composite. It can be clearly seen from Fig. 4 that when the surface of the glassy carbon electrode is modified by the multilayered wall carbon nanotube, the current signal is significantly higher than the other two electrode materials, and the glassy carbon electrode modified by the multilayer wall nanotube is The current signal can maintain a stable level after it is increased. In addition, it can be calculated from this experiment that the glassy carbon electrode, the oxidized cerium oxide nanoparticle composite modified glassy carbon electrode and the multi-walled nanocarbon tube-alumina coated dioxide The sensitivity of the glass-carbon electrode modified by the granules of granules was 0.679, 0.663 and 126.247 μΑ/mM, respectively, and the detection limits were 1.57, 2.98, and 1.42 μΜ, respectively. Therefore, it can be known that 'when multi-walled carbon nanotubes are added At the same time, the sensitivity can be increased by about 190 times compared with the glassy carbon electrode, and a lower concentration can be detected. The response time of the multi-walled carbon nanotube-alumina-coated cerium oxide nanoparticle composite modified glassy carbon electrode is less than 7 seconds, while the other two electrodes are less than 12 seconds, which also proves the multi-layer wall The carbon nanotubes do increase the specific surface area of the electrode and relatively reduce the response time of detecting nicotine. The illustration in Fig. 4 is a glassy carbon electrode, a cupric oxide coated two 16 201035544 oxidized cannamid' granule composite modified glassy carbon electrode, a multi-layered nanocarbon 爹-aluminum oxychloride coated cerium oxide The calibration curve of different concentrations of nicotine was detected by the rice particle composite modified glassy carbon electrode. Based on all the above results, we can understand that the multi-walled carbon nanotube-dioxide-coated oxidized second nanoparticle composite modified glassy carbon electrode is indeed capable of rapidly increasing the current signal for catalyzing the reaction of nicotine. High sensitivity and low concentration detection, response time less than 7 seconds, is a chemical sensor that can effectively detect nicotine. Example 4: Electrode poisoning reaction In electrochemical experiments, sometimes the signal is degraded due to the inappropriate working voltage, so we will test the glassy carbon electrode modified by the nanoparticle composite to prove No excessive operating voltage is generated and the electrode is poisoned. 1. Detection conditions and methods: At the operating voltage of 0·7 V, respectively, the glassy carbon electrode, the multi-walled carbon nanotubes, the aluminum oxide coated cerium oxide nanoparticle modified glassy carbon electrode, and the ruthenium After stirring for 1 sec. in a stirred solution of M pBS (pH 8 〇), 1 〇μΜ of nicotine was added for electrochemical reaction and the current signal was continuously monitored. 201035544 2 ·Results. As shown in Figure 5, the current is generated with the addition of nicotine. Figure 5 (a) and Figure 5 (b) are glass carbon electrodes, multi-walled non-rice tube - alumina coating The erbium reaction record of nicotine was measured under the glass carbon electrode modified by cerium oxide nanoparticle. It can be seen that the current generated by adding the multi-walled carbon nanotubes is less than the current signal of the simple glassy carbon electrode. In order to increase, in addition, we can also see in Figure 5 that the multi-walled carbon nanotubes of Al2O3 coated cerium oxide nanoparticle modified glassy carbon electrode measure nicotine, after 10 seconds, the signal decays by 105%. The glassy carbon electrode is degraded by 28.6%, which shows that the multi-walled carbon nanotube-Al2O3 coated cerium oxide nanoparticle modified glassy carbon electrode has significant anti-pollution and stable operation for nicotine oxidation reaction. . The above results show that the nanocomposite film modified electrode is quite suitable for use as a nicotine chemical sensor, and it is also proved that the operating voltage does not cause excessive electrode poisoning reaction. It is to be understood that the various embodiments of the present invention are not to be construed as a The spirit and scope of this creative principle. Those skilled in the art of 201035544 will appreciate that this creation may be used to modify multiple forms, structures, and materials. Therefore, the embodiments disclosed herein are intended to be illustrative of the present invention and not to limit the present invention. The scope of this creation should be defined by the scope of the appended patent application and encompasses its legal equivalents and is not limited to the foregoing description. 201035544 [Simple description of the diagram] Figure 1 shows the FESEM surface topography of different electrodes. Figure 1 (a) is the FESEM surface topography of the unmodified glassy carbon electrode; Figure 1 (b) is the third oxidation FESEM surface topography of aluminum-coated cerium oxide nanoparticle modified glassy carbon electrode; Figure 1 (c) Multilayer wall carbon nanotube-alumina coated cerium oxide nano cerium particle modified glassy carbon electrode FESEM surface topography. Figure 2 shows the cyclic voltammograms of the different electrodes. Figure 2 (a) and (b) are cyclic voltammograms of a platinum electrode in a 0.1 M PBS solution at pH 8 with 10 μM nicotine and no nicotine scan; c) and (d) a glassy carbon electrode in a pH of 0.1 M PBS solution with 10 μΜ nicotine and a cyclic voltammogram without nicotine scanning; (e) and (f) are coated with aluminum oxide The cerium oxide nanoparticle composite modified glassy carbon electrode was added with ΙΟμΜ nicotine and a cyclic voltammogram without nicotine scanning in 0.1 M PBS solution at pH 8; (g) and (h) were multi-wall nanocarbon Tube·Al2O3 coated cerium oxide nanoparticle composite modified glassy carbon electrode A cyclic voltammogram of 10 μΜ nicotine and no nicotine scan was added to a pH 8 0.1 M PBS solution. 3 is a glass carbon electrode modified by a multi-walled nanocarbon tube-aluminum oxide coated cerium oxide nanoparticle composite according to the present invention, and different concentrations of nicotine are added to a solution of pH 3 in 0.1 M PBS at 201035544. Linear scan voltammograms, (a) no nicotine added; (b) 5 μΜ; (c) 10 μΜ; (d) 15 μΜ; (e) 25 μΜ; (f) 35 μΜ; (g) Add a 45 μΜ linear sweep voltammogram. Figure 4 (a) unmodified glassy carbon electrode; (b) aluminum oxide coated ruthenium dioxide nanoparticle modified glassy carbon electrode; (c) multi-layered niobium carbon nanotube-alumina coated The cerium oxide nanoparticle-modified glassy carbon electrode was used to detect the amperage at different concentrations of nicotine in a 0.1 M PBS solution at pH 8. Figure 5 (a) unmodified glassy carbon electrode; (b) multi-layered wall carbon nanotube-alumina coated cerium oxide nanoparticle modified glassy carbon electrode in 0.1 M PBS solution at pH 8, Add an amperometric reaction record of 10 μΜ nicotine for 1000 sec at an operating voltage of 0.7 V vs. Ag/AgCl. [Main component symbol description] 21