Chen Dawei, Zhao Yunfeng, Miao Hong, Wu Yongning
Key Laboratory of Food Safety Risk Assessment, Ministry of Health, China National Center for Food Safety Risk Assessment, Beijing 100021, China.
Key Laboratory of Food Safety Risk Assessment, Ministry of Health, China National Center for Food Safety Risk Assessment, Beijing 100021, China.
J Chromatogr A. 2014 Dec 29;1374:268-272. doi: 10.1016/j.chroma.2014.11.070.
This paper presents a new analytical method for the determination of rhodamine B (RB) residue in chili powder and chili oil based on a novel reversed-dispersive solid phase extraction (r-dSPE) and ultra high performance liquid chromatography–high resolution mass spectrometry (UHPLC–HRMS). Chili powder and chili oil samples were first extracted with acetonitrile/water (1:1, v/v) and acetonitrile, respectively. Then, RB from the extract was adsorbed to the polymer cation exchange (PCX) sorbent with the characteristics of ion exchange and reversed-phase retention. Subsequently, the analyte in PCX sorbent was eluted with ammonium hydroxide/methanol (1:99, v/v) through a simple unit device equipped with 1 mL syringe and 0.22 μm nylon syringe filter. All of the samples were analyzed by UHPLC–HRMS/MS on a Waters Acquity BEH C18 column with 0.1% formic acid and 4 mM ammonium formate in water/acetonitrile as the mobile phase with gradient elution. The matrix effect, recovery, and repeatability, within laboratory reproducibility, and the LODs and LOQs of the r-dSPE cleanup method were investigated. The method showed a good linearity (R2 > 0.999) in the ranges of 0.01–1 μg/L and 1–100 μg/L for the analyte. The LODs of RB for chili powder and chili oil samples were 0.5 μg/kg. The average recoveries of RB from the samples spiked at four different concentrations (2, 20, 500 and 5000 μg/kg) were in a range from 76.7 to 104.9%. Results showed that the proposed method was simple, fast, economical and effective for the determination of RB in chili powder and chili oil. Considering the excellent sorptive performance of PCX for RB, further work should be done to evaluate the usefulness of the PCX in r-dSPE for the clean-up and analyses of other trace-level alkaline contaminants.
本文提出了一种基于新型反相分散固相萃取（r-dSPE）和超高效液相色谱-高分辨率质谱（UHPLC-HRMS）测定辣椒粉和辣椒油中罗丹明B（RB）残留量的新分析方法。辣椒粉和辣椒油样品首先分别用乙腈/水（1:1，v/v）和乙腈进行萃取。然后，提取物中的RB通过离子交换和反相保留特性吸附到聚合物阳离子交换（PCX）吸附剂上。随后，通过配备1 mL注射器和0.22μm尼龙注射器滤器的简单装置，用氢氧化铵/甲醇（1:99，v/v）洗脱PCX吸附剂中的分析物。所有样品均在Waters Acquity BEH C18柱上，以0.1%甲酸和4 mM甲酸铵的水/乙腈溶液为流动相进行梯度洗脱，通过UHPLC-HRMS/MS进行分析。研究了r-dSPE净化方法的基质效应、回收率、重复性、实验室内重现性以及检测限（LOD）和定量限（LOQ）。该方法在分析物浓度为0.01-1μg/L和1-100μg/L范围内显示出良好的线性（R2>0.999）。辣椒粉和辣椒油样品中RB的LOD为0.5μg/kg。在四个不同浓度（2、20、500和5000μg/kg）加标样品中，RB的平均回收率为76.7%-104.9%。结果表明，所提出的方法用于测定辣椒粉和辣椒油中的RB简单、快速、经济且有效。考虑到PCX对RB具有优异的吸附性能，应进一步开展工作以评估PCX在r-dSPE中用于净化和分析其他痕量碱性污染物的实用性。
