Biuck HABIBI
,
Mehri ABAZARI
,
Mohammad Hossien POURNAGHI-AZAR
催化学报
doi:10.1016/S1872-2067(11)60438-5
A simple and sensitive electrochemical detection of caffeine (CAF) using a single-walled carbon nanotubes on carbon-ceramic electrode (SWCNT/CCE) is reported. CAF was oxidized at the surface of the modified electrode to produce an anodic peak at 1.38 V versus the saturated calomel electrode in 0.01 mol/L, pH 1.7 H2SO4 solution in cyclic voltammetry. The experimental parameters, namely, type of electrolyte, pH value, and amount of SWCNTs casted, were optimized. Using the optimum conditions, the anodic peak current in differential pulse voltammetry was linear with CAF concentration in the range of 2.5×10-7-1.0×10-4 mol/L. The detection limit was 1.2×10-7 mol/L (S/N=3). The modified electrode exhibited good stability and can be easily regenerated. The relative standard deviation of the peak current obtained for a 5.0×10-5 mol/L CAF solution was 3.0%. The influence of some important biological compounds, namely, ascorbic acid, do-pamine, and uric acid and addictive compounds like codeine, morphine, and acetaminophen on the CAF anodic peak current was examined. The method was successfully applied for the determination of CAF in some practical samples.
关键词:
caffeine
,
electrocatalysis
,
electrochemical determination
,
single-walled carbon nanotube
,
carbon-ceramic electrode
常怀春
,
郭兴家
,
张来启
高分子材料科学与工程
合成了咖啡因印迹酚醛吸附树脂,采用静态和动态吸附法考察了分子识别特性。Scatchard分析表明,咖啡因印迹酚醛吸附树脂具有特定的高亲和性结合位点,其离解常数和最大吸附量为Kd1=26.8 mg/L,Qmax1=13.7 mg/g,低亲和性结合位点的离解常数和最大吸附量为Kd2=114 mg/L,Qmax2=28.5 mg/g。在动态条件下,浓度为400 mg/L的咖啡因溶液以3BV/h的流速流经树脂床时,在第26BV出现穿透;用1 mol/L的盐酸以1.5 BV/h的流速进行洗脱,在4BV的洗脱率达到97.5%。
关键词:
咖啡因
,
分子印迹
,
酚醛吸附树脂
,
分子识别
常怀春
,
陈凤清
高分子材料科学与工程
采用静态吸附法研究了自制咖啡因印迹酚醛吸附树脂(CIPS)和非印迹酚醛吸附树脂(NIPS)对咖啡因的吸附.结果表明,在一定的温度和浓度范围内CIPS和NIPS对咖啡因的吸附数据符合Freundlich方程,说明吸附为优惠吸附;对吸附数据进行数学处理,求得了咖啡因在CIPS和NIPS上的吸附焓变在-19 kJ/mol～-31 kJ/mol范围,表明咖啡因与酚羟基的作用力为氢键作用,吸附是放热过程;求得的自由能变和熵变为负值,说明吸附过程是自发进行的.
关键词:
分子印迹聚合物
,
酚醛吸附树脂
,
咖啡因
,
吸附
,
热力学
