Kachoosangi Roohollah Torabi, Wildgoose Gregory G, Compton Richard G
Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, UK OX1 3QZ.
Analyst. 2008 Jul;133(7):888-95. doi: 10.1039/b803588a. Epub 2008 May 1.
A sensitive electroanalytical methodology for the determination of capsaicin using adsorptive stripping voltammetry (AdsSV) at a multiwalled carbon nanotube modified basal plane pyrolytic graphite electrode (MWCNT-BPPGE) is presented. This analytical method is then further developed using a multiwalled carbon nanotube screen-printed electrode (MWCNT-SPE) demonstrating the proof-of-concept that this approach can easily be incorporated into a sensing device which is both facile to use and inexpensive to produce. Capsaicin is the chemical responsible for the hot taste of chilli peppers, and measuring the concentration of capsaicin is an indicator of how hot any given chilli pepper, hot sauce and other related foodstuffs are. Standard additions plots for AdsSV of capsaicin at open circuit potential at a MWCNT-BPPGE exhibits two linear ranges, from 0.5 to 15 microM and from 15 to 60 microM. Using the first range of calibration curve, a detection limit of 0.31 microM (based on 3sigma) is obtained. The plot of standard additions of capsaicin determined using the disposable MWCNT-SPE shows a linear range between 0.5 and 35 microM and a detection limit of 0.45 microM. MWCNT-BPPGE and MWCNT-SPE are successfully utilized for the determination of capsaicin in real samples, such as a few commercially available hot pepper sauces, and the determined values are in excellent agreement and correlation with the average Scoville unit values reported in the literature for these sauces. To the best of our knowledge, this is the first electroanalytical method using MWCNT-BPPGE or MWCNT-SPE reported for the determination of capsaicin. This method offers advantages such as precision and objectivity over the well-known but potentially subjective Scoville method (based on organoleptic testing by human tasting panels) and is facile and inexpensive compared to existing HPLC methods.
本文介绍了一种灵敏的电分析方法，用于在多壁碳纳米管修饰的基面热解石墨电极（MWCNT-BPPGE）上采用吸附溶出伏安法（AdsSV）测定辣椒素。然后，使用多壁碳纳米管丝网印刷电极（MWCNT-SPE）进一步开发了该分析方法，证明了这种方法可以轻松集成到易于使用且生产成本低廉的传感设备中的概念验证。辣椒素是导致辣椒产生辣味的化学物质，测量辣椒素的浓度可指示任何给定辣椒、辣椒酱和其他相关食品的辣度。在MWCNT-BPPGE上，辣椒素在开路电位下的AdsSV标准加入图呈现两个线性范围，分别为0.5至15微摩尔/升和15至60微摩尔/升。使用校准曲线的第一个范围，获得了0.31微摩尔/升（基于3σ）的检测限。使用一次性MWCNT-SPE测定的辣椒素标准加入图显示线性范围为0.5至35微摩尔/升，检测限为0.45微摩尔/升。MWCNT-BPPGE和MWCNT-SPE成功用于测定实际样品中的辣椒素，如几种市售辣椒酱，测定值与文献报道的这些辣椒酱的平均史高维尔单位值具有极好的一致性和相关性。据我们所知，这是首次报道使用MWCNT-BPPGE或MWCNT-SPE测定辣椒素的电分析方法。与著名但可能主观的史高维尔方法（基于人类品尝小组的感官测试）相比，该方法具有精度和客观性等优点，并且与现有的HPLC方法相比，操作简便且成本低廉。
