Abstract: An electrochemical method for the determination of capsaicin was established using an unmodified screen-printed electrode. The effects of ethanol ratio, electrolyte solution variety, pH value and KCl concentration on the determination of capsaicin by cyclic voltammetry using the screen-printed electrode were studied. The feasibility of the method was tested by stability, precision, detection limit and recovery. Results showed that the optimal parameters for the determination of capsaicin by using this unmodified screen-printed electrode were as follows: 10% ethanol, pH 1 and 80 mmol/L KCl, and Britton-Robison, CH3COOH—CH3COONa and NaH2PO4—Na2HPO4 electrolyte solutions were all suitable for the determination of capsaicin. Linear calibration curve for capsaicin in the range of 0.80~107.72 μmol/L was obtained with a detection limit of 0.13 μmol/L. In addition, the method was of good stability, precision and recovery, which was consistent with the determination of capsaicin by HPLC. Therefore, this method could be used for the rapid determination of capsaicin.
 BENNETT D J, KIRBY G W. Constitution and biosynthesis of capsaicin[J]. Journal of the Chemical Society C: Organic, 1968, 4: 442-446.  ZHONG F, LIU Z, HAN Y, et al. Electrochemical sensor for sensitive determination of capsaicin using Pd decorated reduced graphene oxide[J]. Electroanalysis, 2019, 31(6): 1 182-1 188.  FATTORI V, HOHMANN M S N, ROSSANEIS A C, et al. Capsaicin: current understanding of its mechanisms and therapy of pain and other pre-clinical and clinical uses[J]. Molecules, 2016, 21(7): 844-876.  SHIN Y H, KIM J M, PARK K. The effect of capsaicin on salivary gland dysfunction[J]. Molecules, 2016, 21(7): 835-844.  O′NEILL J, BROCK C, OLESEN A E, et al. Unravelling the mystery of capsaicin: a tool to understand and treat pain[J]. Pharmacological Reviews, 2012, 64(4): 939-971.  SHARMA S K, VIJ A S, SHARMA M. Mechanisms and clinical uses of capsaicin[J]. European Journal of Pharmacology, 2013, 720(1-3): 55-62.  SATYANARAYANA M N. Capsaicin and gastric ulcers[J]. Critical Reviews in Food Science and Nutrition, 2006, 46(4): 275-328.  刘晓庚, 徐欣东, 刘琴, 等. 循环伏安法测定辣椒中辣椒碱的检测条件优化[J]. 食品工业科技,2020,41(4):218-223;228.  YARDIM Y, ENTÜRK Z. Electrochemical evaluation and adsorptive stripping voltammetric determination of capsaicin or dihydrocapsaicin on a disposable pencil graphite electrode[J]. Talanta, 2013, 112: 11-19.  GIBBS H A A, O'GARRO L W. Capsaicin content of West Indies hot pepper cultivars using colorimetric and chromatographic techniques[J]. HortScience, 2004, 39(1): 132-135.  ZHANG Q, HU J, SHENG L, et al. Simultaneous quantification of capsaicin and dihydrocapsaicin in rat plasma using HPLC coupled with tandem mass spectrometry[J]. Journal of Chromatography B, 2010, 878(24): 2 292-2 297.  GARCÉS-CLAVER A, ARNEDO-ANDRÉS M S, ABADÍA J, et al. Determination of capsaicin and dihydrocapsaicin in capsicum fruits by liquid chromatography-electrospray/time-of-flight mass spectrometry[J]. Journal of Agricultural and Food Chemistry, 2006, 54(25): 9 303-9 311.  PEÑA-ALVAREZ A, RAMÍREZ-MAYA E, ALVARADO-SUÁREZ L Á. Analysis of capsaicin and dihydrocapsaicin in peppers and pepper sauces by solid phase microextraction-gas chromatography-mass spectrometry[J]. Journal of Chromatography A, 2009, 1216(14): 2 843-2 847.  YANG Q, ZHU J, MA F, et al. Quantitative determination of major capsaicinoids in serum by ELISA and time-resolved fluorescent immunoassay based on monoclonal antibodies[J]. Biosensors and Bioelectronics, 2016, 81: 229-235.  MPANZA T, SABELA M I, MATHENJWA S S, et al. Electrochemical determination of capsaicin and silymarin using a glassy carbon electrode modified by gold nanoparticle decorated multiwalled carbon nanotubes[J]. Analytical Letters, 2014, 47(17): 2 813-2 828.  DE LEÓN ZAVALA E D, RODRÍGUEZ L M T, MONTES-ROJAS A, et al. Study of electrochemical determination of capsaicin and dihydrocapsaicin at carbon paste electrodes modified by β-cyclodextrin[J]. Journal of Electroanalytical Chemistry, 2018, 814: 174-183.  王燕. 基于碳材料的辣椒素电化学传感器的制备及应用研究[D]. 广州: 华南理工大学, 2017.  WANG Y, HUANG B B, DAI W L, et al. Sensitive electrochemical capsaicin sensor based on a screen printed electrode modified with poly(sodium 4-styrenesulfonate) functionalized graphite[J]. Analytical Sciences, 2017, 33(7): 793-799.  GB/T 21266—2007, 辣椒及辣椒制品中辣椒素类物质测定及辣度表示方法[S]. 北京: 中国标准出版社, 2007.  国家食品药品监督管理总局. 总局关于发布《食用油脂中辣椒素的测定》食品补充检验方法的公告(2018年第26号)[EB/OL]. (2018-02-27)[2020-02-16]. http://samr.cfda.gov.cn/WS01/CL0087/225540.html.  SØPSTAD S, IMENES K, JOHANNESSEN E A. Hybrid electrochemical sensor platform for capsaicin determination using coarsely stepped cyclic squarewave voltammetry[J]. Biosensors and Bioelectronics, 2019, 130: 374-381.  NASKAR H, GHATAK B, BISWAS S, et al. Electrochemical detection of capsaicin using yttrium oxide nanoparticles modified graphite paste electrode (Y2O3/GPE)[C]. 2019 IEEE International Symposium on Olfaction and Electronic Nose (ISOEN). Fukuoka: IEEE, 2019: 1-3.  WANG Y, HUANG B, DAI W, et al. Sensitive determination of capsaicin on Ag/Ag2O nanoparticles/reduced graphene oxide modified screen-printed electrode[J]. Journal of Electroanalytical Chemistry, 2016, 776: 93-100.  KACHOOSANGI R T, WILDGOOSE G G, COMPTON R G. Carbon nanotube-based electrochemical sensors for quantifying the ‘heat’of chilli peppers: the adsorptive stripping voltammetric determination of capsaicin[J]. Analyst, 2008, 133(7): 888-895.