摘要
文中建立了测定食品中Cu的二元双波长可见吸收光谱(DWO-VIS)法。在pH 6.86的Tris-盐酸缓冲介质中,丽春红S与Cu(Ⅱ)发生反应,在可见光区生成具有一个明显正吸收峰和一个明显负吸收峰的离子缔合物。最大正吸收波长和最大负吸收波长分别为445 nm和510 nm。Cu(Ⅱ)在0.06~1.6 mg/L(正吸收,445 nm)、0.04~1.6 mg/L(负吸收,510 nm)和0.03~1.6 mg/L(DWO-VIS,445 nm+510 nm)内遵从朗伯-比尔定律,表观摩尔吸光系数(κ)分别为8.70×10~3(正吸收法)、2.04×10~4(负吸收法)和2.92×10~4(DWO-VIS法)L/(mol·cm),定量限分别为0.62、0.38和0.26 mg/100 g。还探讨了吸收光谱特征、适宜反应条件及共存物质的影响。双波长法用于饼干、面条及奶粉中Cu的测定,加标回收率为97.9%~102%,相对标准偏差RSD(n=5)为2.5%~2.8%。
A new dual-wavelength visible absorption spectroscopy method （DWO-VIS） for quantifying copper content in food was established. In tris-hydrochloric acid buffer medium of pH 6.86, ponceau S reacted with copper （ Ⅱ） to form an ion association complex with has a positive absorption peak and a negative absorption peak in the visible area. The maximum positive absorption wavelength and the maximum negative absorption wavelength were located at 445 nm and 510 nm respectively. Copper（ Ⅱ ） obeys Lombard Beer＇s law in the mass concentration range of 0.06 - 1.6 mg/L（positive absorption,445 nm） and 0.04 - 1.6 mg/L（ negative absorption,510 nm） and 0.03 - 1.6 mg/L （DWO-VIS ,445 nm ＋ 510 nm） respectively. Their apparent molar absorptivity （K） were 8.70 × 103（positive ab- sorption method） and 2.04 × 104 （ negative absorption method） and 2.92 ×104 （ DWO-VIS method） L/（ mol · cm）, respectively. The limit of quantitation were 0.62,0.38 and 0.26 rag/100 g respectively. The absorption spectral characteristic and optimum reaction conditions and effect of the coexistence material were studied. The dual-wave- length visible absorption spectroscopy method was applied to determine the content of copper in biscuits and noodles and milk powder with spiked recoveries and relative standard deviation （RSD） （n = 5） found were in the ranges of 97.9% - 102% and 2.5% -2.8% respectively.
作者
江虹
吴征真
王芳
冉纯民
曾庆瑞
程乙真
JIANG Hong;WU Zheng-zhen;WANG Fang;RAN Chun-min;ZENG Qing-rui;CHENG Yi-zhen(College of Chemistry and Chemical Engineering, Collaborative Innovation Center for Green Development in Wuling Mountain Areas, Yangtze Normal University, Chongqing 408100,China)
出处
《食品与发酵工业》
CAS
CSCD
北大核心
2018年第1期253-257,共5页
Food and Fermentation Industries
基金
重庆市教委科技基金资助项目(KJ1401226)
长江师范学院科技基金资助项目(2016CXX088)
关键词
CU
丽春红S
双波长-可见吸收光谱法
copper
ponceau S
dual-wavelength visible absorption spectroscopy method
