粮食中重金属铅镉电化学快速检测方法研究

建立一种基于稀酸提取技术实现粮食中铅镉同时测定的电化学快速检测方法。通过优化提取液的种类和底物液的成分,提高方法准确性和灵敏度,实现粮食中铅和镉同时检测,并且通过科学系统的评价方案对所建立的检测方法进行性能考察,提高检测方法的稳定性。该方法镉的检出限为0.005 mg/kg,定量限为0.012 mg/kg,铅的检出限0.002 mg/kg,定量限为0.004 mg/kg,回收率范围98%～120%,相对标准偏差均小于15%,可在15 min内完成2种元素的同时检测,检测效率高。     

氧化铝掺杂碳糊电极对浆果中铅的快速检测及其干扰分析

目的 开发氧化铝掺杂碳糊电极测定浆果中铅(Pb)的电化学快速检测方法。方法 以浆果为研究对象,采用制备的氧化铝掺杂修饰碳糊电极(alumina doped carbon paste electrode, Al₂O₃-CPE),以方波阳极溶出伏安法(square wave anodic stripping voltammetry, SWASV)检测其中的Pb(Ⅱ)。分析电极的检测性能,优化电解液组成,确定检测条件。通过比较匀浆/超声提取和湿法消解两种前处理,确定适宜浆果中Pb快速检测的前处理方法;并对浆果基质中主要干扰因素进行分析。结果 采用M醋酸:M醋酸钠=1.05的电解液,建立的SWASV检测Pb(Ⅱ)的线性范围为0.5～80.0μg/L,r²=0.9976。匀浆/超声提取-SWASV检测结果可达到湿法消解-电感耦合等离子体质谱法(inductively coupled plasma-mass spectrometry, ICP-MS)的95.05%～106.11%。K(Ⅰ)、Ca(Ⅱ)、Mg(Ⅱ)和花青素对Pb(Ⅱ)...     

金纳米颗粒修饰分子印迹电化学传感器快速检测蔬菜中吡虫啉含量

目的 将分子印迹技术、电化学技术和纳米颗粒修饰技术相结合,开发蔬菜中吡虫啉快速检测技术。方法 采用金纳米颗粒修饰玻碳电极提高其电子转移速率, 通过分子印迹技术在电极表面聚合膜材料制备电化学传感器,利用循环伏安法和差分脉冲法表征传感器性能,基于传感器对目标农药分子的特异性吸附建立农药快速检测方法。结果 以吡虫啉为模板分子,邻苯二胺为功能单体,基于金纳米颗粒修饰的玻碳电极构建了一种吡虫啉分子印迹电化学传感器,该传感器可实现对吡虫啉的特异性识别检测,在1.0×10-11~1.0×10-4 mol/L浓度范围内,吡虫啉线性关系良好,相关系数为0.9951,检出限 为3.3×10-12 mol/L,小白菜样品加标回收率为91.86%~102.25%,相对标准偏差为1.98%~3.19%。结论 本研究制备的传感器具有优良的选择性、重复性和稳定性,适用于蔬菜中吡虫啉的快速检测,为当前农残速测产品的开发提供了参考。     

基于纳米复合物修饰的纳米多孔金电化学传感器对大米中镉含量的检测

本文制备了功能化氧化石墨烯/壳聚糖/离子液体纳米复合物修饰的纳米多孔金电极(fGO/CS/IL/NPG/GCE),并运用于大米中Cd²⁺的检测。通过阳极溶出伏安法(Anodic Stripping Voltammetry, ASV),优化了Cd²⁺的检测条件,确定最佳的检测条件为功能化氧化石墨烯/壳聚糖/离子液体纳米复合物(fGO/CS/IL)滴加量为5μL,富集电位为-0.8 V,富集时间为100 s,缓冲液为pH=4的醋酸盐缓冲液(ABS)。在最佳检测条件下,结果表明,在100 nmol/L～1 000μmol/L浓度范围内,Cd²⁺的溶出峰电流与浓度具有良好的线性关系,曲线方程为：Current (μA)=2.296 C²⁺_Cd+2.225 (R²=0.990),最低检测限为100 nmol/L,电极具有良好的重复性和稳定性。     

原位快速检测重金属镉的研究进展

镉是一种对环境和人体健康有害的重金属,虽然基于原子吸收光谱仪和电感耦合等离子体质谱仪等大型仪器的常规检测方法准确度高,但不能满足快速现场检测和高通量筛查的需求。镉的原位快速检测技术,可以在粮食安全、农业物联网、生物育种和环境监测等领域提供一种新型、高效、实时的方法,特别是在筛选不同镉吸收和积累特性的植物品种方面具有很大的应用潜力。本文从检测技术原理和特点入手,总结了针对动植物体内重金属镉的快速原位检测的不同技术,如电化学传感技术、荧光传感技术、光学传感器技术等,及其在食品安全监测、风险评估和在生物体内的迁移、转化和积累等领域的研究进展、应用前景和发展方向,以期为相关的科研工作提供技术参考。     

蔬菜中农残快速检测方法的研究

以酶抑制率法快速检测蔬菜中有机磷和氨基甲酸酯类农药的原理为依据,采用一种新的进样方式,改良了原有农残快速检测技术的弊病,节省了检测的时间和试剂的用量。同时,该方法对几种主要禁用农药检出结果的准确度,达到了国标法所规定的最低检出限的要求。     

蔬菜硝酸盐快速检测方法的研究

以常见叶菜大白菜、小白菜、小油菜、波菜、芹菜为试材,依据NO3-与二苯胺在酸性介质(浓硫酸)中的显色反应,设计了一种建立在目视比色法基础之上,进行比色的一种快速检测叶菜中NO3-含量的方法。这种方法测定时间短、操作简便、快速,无需特殊处理和昂贵的仪器,用于半定量分析,准确度、精密度、灵敏度满足要求。     

电化学方法在食品化学污染物快速检测中的研究进展

近年来,食品化学污染物的有效控制与快速、灵敏检测受到了政府和民众的高度重视。传统的分析检测方法存在检测时间长、样品前处理复杂等缺点,难以满足实际检测的需求。电化学方法由于其仪器简单、分析速度快、检测灵敏度高等优点在食品化学性污染物检测方面越来越受到关注。本文介绍了电化学检测方法的主要类型及其基本原理,重点阐述了电化学分析方法在食品中重金属、农药、抗生素等化学残留物检测中的应用研究。最后,文章还对电化学方法在食品安全快速检测领域中的发展趋势进行了展望。     

电化学方法在食品化学污染物快速检测中的 研究进展

近年来,食品化学污染物的有效控制与快速、灵敏检测受到了政府和民众的高度重视。电化学方法由于其仪器简单、分析速度快、检测灵敏度高等优点在食品化学性污染物检测方面越来越受到关注。本文介绍了电化学检测方法的主要类型及其基本原理,重点阐述了电化学分析方法在食品中重金属、农药、抗生素等化学残留物检测中的应用研究。最后,文章还对电化学方法在食品安全快速检测领域中的发展趋势进行了展望。     

酶抑制法快速检测蔬菜中农药残留灵敏度与准确性的研究

本文对酶抑制法快速检测蔬菜中农药残留的灵敏度与准确性进行验证,分别使用酶抑制快速检测方法与气相色谱方法对10类50份蔬菜样品进行敌敌畏等10种有机磷农药残留量的检测。结果表明,蔬菜中农药残留的酶抑制快速检测方法灵敏度与准确性可以满足快检需求,其对50批次实际样品的检测结果与气相色谱方法检测结果基本相符,能够满足基层市场监管部门和果蔬市场监控蔬菜质量的需求。     

双酚A在离子液体修饰碳糊电极上的电化学行为及测定

制备1-氰乙基-3-甲基咪唑六氟磷酸盐离子液体修饰碳糊电极,研究双酚A（bisphenol A,BPA）在离子液体修饰碳糊电极上的电化学行为。结果表明,在0.1 mol/L B-R缓冲液（pH 10.0）中,BPA在0.415 V处产生一良好的氧化峰,具有明显的电催化增敏作用。BPA的氧化过程为伴随有质子转移的表面吸附控制的不可逆过程,其电极反应速率为0.32/s。建立了示差脉冲伏安法测定痕量BPA的方法,线性范围为3.0×10－7～6.0×10－5 mol/L,检出限为5.0×10－8 mol/L（RSN=3）。并将其用于奶瓶样品中迁移BPA的测定,结果表明该传感方法为直接电化学检测BPA提供了一种新的思路。     

功能化多壁碳纳米管修饰玻碳电极测定沙丁胺醇

制备多壁碳纳米管修饰玻碳电极,应用循环伏安法研究沙丁胺醇在修饰电极上的电化学行为。结果表明,碳纳米管修饰电极对沙丁胺醇的氧化有良好的电催化活性,在最佳测试条件下,氧化峰电位负移至0.601V,比裸玻碳电极负移90mV,氧化峰电流与沙丁胺醇浓度在2.09×10-7～2.27×10-6mol/L范围内呈良好线性关系,检出限达1.9×10-7mol/L。该电极具有良好的重现性和稳定性。     

基于氧化氮掺杂石墨烯修饰碳糊电极高灵敏测定辣椒素

采用一步水热合成法制备氧化氮掺杂石墨烯(nitrogen-doped graphene oxide,NGO),采用X射线光电子能谱,透射电子显微镜对其进行表征。采用滴涂法制备了氧化氮掺杂石墨烯修饰碳糊电极(nitrogen-doped graphene oxide/carbon paste electrode,NGO/CPE),研究辣椒素在NGO/CPE上的电化学行为,发现与裸碳糊电极相比,NGO/CPE能显著增加辣椒素的响应信号。优化了NGO质量浓度、富集时间、介质p H值等实验参数,利用差分脉冲伏安法对辣椒素进行测定,辣椒素氧化峰电流与其质量浓度在5.0~1 200μg/L范围内呈良好线性关系,检出限为2.0μg/L(RSN=3)。将本方法用于辣椒粉样品中辣椒素含量检测,结果与比色法基本一致。     

Determination of Ascorbic Acid in Commercial Juices,on a Modified Carbon Paste Electrode,by Using a Taguchi Experimental Design

In this paper, a simple and rapid analytical method development for ascorbic acid determination by using differential pulse voltammetry method on copper(II)-phthalocyanine carbon paste electrode is shown. For this, several parameters, such as copper(II)-phthalocyanine (gram)/carbon (gram)/Nujol (millilitre) ratio, supporting electrolyte, pH and some others have been studied. In order to know the copper(II)-phthalocyanine influence on voltammetry peak height, a comparison between the analytical behaviour of a chemically modified carbon paste electrode and a conventional carbon paste electrode was carried out. The experimental conditions have been optimised by means of the experimental design using the Taguchi methodology. The catalytic oxidation peak current showed a linear depending on the ascorbic acid concentration in the range between 0.88 and 10.03 mg L⁻¹, with the detection limit of 0.55 mg L⁻¹. The proposed procedure was successfully applied to the determination of ascorbic acid in fruit juices without previous preparation and was compared with HPLC method applied at the same samples previously filtered.     

Sensitive and Selective Determination of Riboflavin in Food and Pharmaceutical Samples Using Manganese (III) Tetraphenylporphyrin Modified Carbon Paste Electrode

A chemically modified electrode was constructed by incorporating manganese (III) tetraphenyl porphyrine into a carbon paste matrix. The modified electrode was used as a sensitive electrochemical sensor for measuring of riboflavin. The constructed electrode exhibited catalytic properties for the electro-oxidation of riboflavin and lowered the over potential for the oxidation of this compound; consequently, the corresponding peak currents of riboflavin increased significantly. The modified electrode showed a near-Nernstian behavior for electro-oxidation of riboflavin hence, it could be a suitable voltammetric sensor for the fast and easy determination of riboflavin. A linear response in concentration range 1.0 × 10^?8 – 1.0 × 10^?5 M was obtained with a detection limit of 8.0 × 10^?9 M (S /n = 3) for the determination of riboflavin. The electrode showed long-term stability and the standard deviation of the slope obtained after repeated calibration during a period of 3 months was 3.5% (n = 10). The modified electrode was used for differential pulse voltammetric determination of riboflavin in pharmaceutical and food samples.     

Simultaneous Electrochemical Determination of Caffeine and Vanillin by Using Poly(Alizarin Red S) Modified Glassy Carbon Electrode

Poly(alizarin red S) conducting polymer was prepared on glassy carbon electrode (GCE) surfaces, and the functionalized electrode was used for the simultaneous determination of caffeine (CAF) and vanillin (VAN). The peak potential separation for caffeine and vanillin was about 600 mV in 0.1 M acetate buffer solution (pH 4.0). The peak currents for the oxidation of both CAF and VAN are increased at poly(alizarin red S) (poly(ARS)) functionalized electrode, which makes it suitable for simultaneous detection of these compounds. The square wave voltanmmetry peak current of VAN was linear with the concentration of VAN from 0.5 to 250 μM in the presence of 250 μM CAF. The detection limit of VAN was found to be 0.06 μM in the presence of CAF. At the same time, the peak current of CAF was linear with the concentration of CAF from 10 to 450 μM with a detection limit of 0.8 μM (S/N = 3) in the presence of 30 μM VAN. The poly(ARS) functionalized GCE has good reproducibility and high stability. In addition, the proposed method was successfully applied to determine CAF and VAN in energy drink and vanilla sugar samples with good results.     

Square Wave Voltammetric Determination of Fomesafen Herbicide Using Modified Nanostructure Carbon Paste Electrode as a Sensor and Application to Food Samples

Cyclic and square wave voltammetric measurements were performed to deduce the electrochemical behavior of fomesafen herbicide on the prepared carbon nanotube paste electrodes. Fomesafen has created a well-defined cathodic peak at ?540 mV (vs. Ag/AgCl), but no corresponding oxidation peak has appeared on the reverse scan. The influence of the pH on the electro-reduction peak was tested at various pH values, and the E _p versus pH plot suggested that protons are involved in reduction process. Electrochemical studies showed that –NO₂ group was responsible for the reduction process. A linear relationship has been constructed in the concentration range of 0.30–40 mg/L. The limits of detection and quantification values were obtained as 0.089 and 0.297 mg/L, respectively. Fomesafen was determined in the presence of some well-known pesticides, and the extent of recoveries of 5 mg/L fomesafen in the presence of equal amounts of pesticides anilazine, pymetrozine, and triflumizole was 103.7 ± 0.9, 94.3 ± 0.4, and 97.9 ± 0.5 %, respectively (n = 3). The accuracy of the recommended method was further proved by the determination of fomesafen in spiked real samples such as apricot juice, cherry juice, and lake water with a relative error of ?4.2, ?2.8, and ?1.8 %, respectively. The obtained results suggest that the recommended method is sufficiently accurate, selective, and precise.     

离子液体修饰玻碳电极测定金银花中的总黄酮

用1- 丁基-3- 甲基咪唑六氟磷酸盐([BMIM]PF6)疏水性离子液体作修饰剂制作[BMIM]PF6- 修饰玻碳电极。在0.2mol/L 磷酸盐缓冲液(pH7.0)中,运用差示脉冲溶出伏安法(DPSV)研究木犀草素在修饰电极上的电化学行为,建立测定金银花中总黄酮含量的新方法。研究表明,该修饰电极降低了木犀草素的氧化还原峰电位,增大了其氧化还原反应的峰电流。木犀草素氧化峰电流与其浓度在1.0 × 10-10～1.6 × 10-8mol/L 范围内呈良好的线性关系,检出限达到3.2 × 10-11mol/L,回收率为98.7%～103.6%。该法操作简单、快速、灵敏、准确,可用于金银花中总黄酮的测定。     

纳米金修饰碳糊电极上沙丁胺醇的电化学研究

制备纳米金修饰碳糊电极,采用循环伏安法和方波伏安法研究沙丁胺醇(Sal)在修饰电极上的电化学行为。纳米金修饰碳糊电极与裸碳糊电极相比,显著提高Sal的氧化峰电流,氧化峰电位负移50mV,提高了测定Sal的灵敏度。实验表明：氧化峰电流与Sal浓度在0.471～64.2μmol/L范围内呈良好线性关系,检出限为0.15μmol/L(RSN=3)。对40.7μmol/L的Sal进行11次平行测定,RSD 1.7%。所建立的方法可用于血样和尿样中Sal含量的测定。