| 摘要: | 本研究以超臨界二氧化碳流體法合成金奈米顆粒於石墨烯、多壁奈米碳管和碳黑上，尺寸大小接近10 nm，利用貴重儀器SEM、TGA、XRD、TEM分析其表面形貌、金屬含量、顆粒大小、均勻度等，與空氣中製程的金奈米顆粒來比較催化性質，搭配離子液體調配出催化及感測較為有利的組合。
離子液體與適當的碳材組合，電化學訊號獲得良好的改善，為了進一步提升感測電極的靈敏度及選擇性，將碳材、金奈米顆粒及離子液體三者相結合，當利用離子液體作為輔助時，陰離子主導了電化學感測行為，當不同的待測物與牽涉入的酵素，增益效果及行為也不盡相同，使用多種離子液體來做系統性的研究。
非酵素葡萄糖感測器，利用超臨界流體製備的金奈米顆粒比一般空氣中製備的均勻，催化性質較好。以石墨烯為載體的複合材料(不含離子液體)偵測葡萄糖，其電化學感測訊號略低於以多壁奈米碳管為載體者，透過結合離子液體BMPTFSI，進而改善了感測電極的電化學傳輸訊號。抗壞血酸所產生的干擾電流訊號小於5%。測試其重複使用性，應答電流並無太大的衰退情形。
非酵素過氧化氫感測器，運用不同種碳材修飾，其結果為石墨烯和多壁奈米碳管較敏感，碳黑較遜色。加入金奈米顆粒後的碳材擁有更高活性面積和金的催化效果，靈敏度得到提升。加入離子液體後對偵測H2O2的靈敏度都有提升的效果。輔以離子液體抑制氧氣干擾的現象十分有效，能緩解約五分之四的電流干擾訊號。
酵素葡萄糖感測器中，葡萄糖氧化?對親水性的離子液體在氧化還原時有很強的電荷轉移。利用不同離子液體固定葡萄糖酵素並存放在較嚴苛的環境下，室溫空氣環境中存放五天，選擇疏水性離子液體輔助電極有效保存酵素的活性在25℃。
酵素型果糖纈胺酸，使用輔以BMPTFSI離子液體之電極感測性質最佳，加入與人體血液中接近濃度的抗壞血酸、多巴胺和尿酸作為干擾物，仍然能維持97%的應答電流值，說明此三種物種在這裡不構成干擾。放置室溫25℃空氣環境中存放五天，活性排序為與酵素型葡萄糖感測器相同。
由實驗結果得知，對於不同的待測物可藉由石墨烯、金奈米顆粒及離子液體間的互相搭配，而達到最佳的偵測效果，與酵素良好的交互作用還能增加其穩定性及存放時效，顯示這三種材料運用於電化學
感測器上的可行性。
In this study, nanosized Au particles (approximately 10nm in diameter) are uniformly distributed on graphene, carbon nanotubes, and carbon black using a supercritical CO2 fluid (ScCO2). SEM, TGA, XRD, and TEM are adopted to examine microstructures, Au loading amounts, and crystalline of the composites. Compared with the conventional chemical deposition process, (the ScCO2) process produces electrodes with superior electrochemical sensing performance. It is also noted that incorporation of ionic liquids (ILs) in the electrode promotes its detection sensitivity.
To increase sensitivity and selectivity, catalytic gold nanoparticles have been loaded on appropriate carbon nanostructures combining with ionic liquid. It is found that the anions of ILs, instead of the cations dominate the electrochemical sensing performance. For various analysts (and thus various enzymes), different ILs should be used to optimize the electrode properties.
The ScCO2 fluid can highly disperse Au on the carbon supports, leading to an enhanced catalytic activity of Au toward enzymeless glucose sensor. With IL, the Au/graphene electrodes exhibited considerably greater sensing performance than that of the Au/MWCNT electrodes
this trend is opposite to that without IL incorporation. The interference current from AA was less than 5% of the glucose oxidation signal. The sensors have
satisfactory reproducibility and excellent stability.
Various different carbon materials to modify enzymeless H2O2 sensor, and the results indicate graphene and MWCNT are more sensitive than carbon black. Decorating Gold nanoparticle on carbon material could create high reaction area and lead to enhanced catalytic activity for electrochemical sensing. After incorporate with IL, promote the sensitivity of H2O2, and compress the interference of O2. Moreover, the most suitable IL could
release 80% interference current of O2.
Glucose oxidase immobilize on ScCO2Au/Graphene electrode have strong direct electron transfer in reoxide with hydrophilic IL toward enzyme glucose sensor. The electrode immobilize enzyme with different IL and storage in practical environment. As a result of selecting hydrophobic IL could keep enzyme activity in room temperature after five days.
The ScCO2Au/Graphene with BMPTFSI is the most suitable electrode to be an electrochemical fructose valine sensor. The proposed electrode can be performed without significant interference by AA, DA, UA at the concentration levels typically found in the human body and still keep 97% responsible current density for FV. The proposed electrode storage in practical environment after five days, and active series is the same with
enzyme glucose sensor.
To achieve the best detection results or increase stability of enzyme electrode and storage time by means of selecting graphene, gold nanoparticle, and proposed IL for differnet analyst. This study shows they making modify
electrode promising for practical applications. |
