Exploiting Cork as Biosorbent Extraction Phase for Solid-Phase Microextraction to Determine 3-(4-Methylbenzylidene)camphor and 2-Ethylhexyl 4-(Dimethylamino)benzoate in River Water by Gas Chromatography-Mass Spectrometry

In this study, a method for the determination of 3-(4-methylbenzylidene)camphor (4-MBC) and 2-ethylhexyl 4-(dimethylamino)benzoate (OD-PABA) in river water samples employing cork as the SPME (solid-phase microextraction) fiber was developed. The extraction parameters optimized were pH, ionic strength and extraction time and temperature. For the extraction step, the sample pH was studied in univariate experiments while the extraction time, temperature and ionic strength were evaluated using a central composite design. The optimal extraction conditions were sample pH 4.0, extraction time 70 min, sample temperature 80 °C and sodium chloride concentration 6% (m v-1). The limits of quantification for 4-MBC and OD-PABA were 0.1 and 0.01 µg L-1, respectively. The linear correlation coefficients were greater than 0.97 for both analytes and the developed method showed recovery values between 67 and 107%. In an evaluation of the fiber-to-fiber reproducibility (fibers produced by different analysts), the relative standard deviation (RSD) was lower than 11% (n = 6).

本研究开发了一种以软木塞作为固相微萃取（solid-phase microextraction, SPME）纤维的分析方法，用于测定河水样品中的3-(4-甲基亚苄基)樟脑（4-MBC）与2-乙基己基4-(二甲氨基)苯甲酸酯（OD-PABA）。本研究优化的萃取参数包括pH值、离子强度、萃取时间及萃取温度：其中样品pH值采用单变量实验进行考察，萃取时间、温度与离子强度则通过中心复合设计进行评价。最终确定的最优萃取条件为：样品pH值4.0、萃取时间70 min、样品温度80 ℃、氯化钠浓度6%（m v-1）。两种目标分析物的定量限分别为0.1 μg L⁻¹和0.01 μg L⁻¹；两类分析物的线性相关系数均大于0.97，所建立方法的加标回收率介于67%~107%之间。在对不同分析师制备的纤维进行纤维间重现性评价时，相对标准偏差（RSD）小于11%（n=6）。