Gold Nanoparticles and Sensor Technology for Sensitive Ethylene Detection

用于痕量乙烯濃度檢測的金納米傳感器技術

M.M. Blanke^a , R. Shekarriz^b

^aINRES - University of Bonn Auf dem Huegel 6, D-53121 Bonn Germany

^bFluid Analytics, Inc. West Linn, Oregon USA

Abstract
A new electrocatalytic sensor for continuous in-situ measurement of gaseous ethylene (C2H4) in air is presented. The measuring principle is based on ethylene oxidation on a gold-Nafion anode with weak sulphuric acid used as the electrolyte. The small ethylene molecules are trapped in the pores of the nanoporous gold matrix and partly consumed to produce the signal proportional to their concentration in air. The high surface area of the nanoporous gold catalyst renders high sensitivity and fast response in detection of ethylene in air making it particularly suitable for postharvest or plant physiology applications. In the current study, the accuracy was 96-98% with a standard deviation (SD) of 0.05-0.15 μl L-1 C2H4 and a variation coefficient of 0.5- 2%, when the calibration gas of 8 μl L-1 C2H4 was measured after calibration. The measuring range of the device is 0-50 μl L-1 C2H4 with an accuracy of ±5% of reading and displayed resolution of 1 nl L-1. For a 30-s measurement, the instrument draws a ca. 150 ml gas sample and appears suitable for measurement of individual fruit in an open or closed gas system, for continuous sampling or single gas samples. Temperature, humidity, CO2 (optional sensor) and another gas or ethylene analogue like MCP (optional sensor) are displayed concomitantly. The reproducibility of the C2H4 values was 93% with 3 subsequent measurements of a variety of fruits. The unit can be operated on mains or built-in battery providing up to 8 hours operation and weighs 4.5 kg. This makes it portable for in situ ethylene measurement after calibration with an external gas supply and is a better alternative to measurement of ethylene in the head space of a respiration chamber.

介紹了一種用于連續(xù)在線測量空氣中乙烯(C2H4)的新型電催化傳感器。測量原理是以軟硫酸為電解液，在金-鈉離子陽極上進行乙烯氧化。小乙烯分子被困在納米多孔金基質的孔隙中，部分被消耗以產(chǎn)生與其在空氣中濃度成比例的信號。納米多孔金催化劑的高表面積使其在空氣中檢測乙烯時具有高靈敏度和快速響應性，特別適用于采后或植物生理學應用。在本研究中，當標定后測得8μL L^-1 C2H4的標定氣體時，其準確度為96-98%，標準偏差(SD)為0.05-0.15μL-1 C2H4，變異系數(shù)為0.5-2%。該裝置ETH-1010N(Fluid Analytics lnc.)的測量范圍為0-50μl L^-1 (0-50ppm)C2H4，讀數(shù)精度為±5%，顯示分辨率為1 nl L^-1(1ppb)。對于30秒的測量，儀器抽取約150毫升的氣體樣品，并且似乎適合在開放或封閉的氣體系統(tǒng)中測量單個水果，用于連續(xù)取樣或單個氣體樣品。同時顯示溫度、濕度、二氧化碳(可選傳感器)和其他氣體或乙烯類似物，如1-MCP(可選傳感器)。通過對各種水果的3次后續(xù)測量，C2H4值的再現(xiàn)性為93%。該裝置可在電源或內置電池上運行，運行時間長達8小時，重量為4.5千克。這使得外部供氣校準后的現(xiàn)場乙烯測量變得方便，是呼吸室頂部空間乙烯測量的更好替代方法。

Keywords: ethylene, degreening, ethylene scrubber, flower induction, nanotechnology, fruit, 1-MCP, sensor technology, food supply chain

關鍵詞：乙烯；脫綠；乙烯脫除器；花卉誘導；納米技術；水果；1-MCP；傳感器技術；食品供應鏈