A dual-wavelength resonance light scattering ratiometry of biopolymer by its electrostatic interaction with surfactant

A dual-wavelength resonance lighting scattering (DW-RLS) ratiometry is developed to detect anion biopolymer based on their bindings with cation surfactant. Using the interaction of Hyamine 1622 (HM) with fish sperm DNA (fsDNA) as an example, a dual-wavelength resonance light scattering (DW-RLS) ratiometric method of DNA was constructed. In Britton-Robinson buffer controlled medium, fish sperm DNA (fsDNA) could interact with Hyamine 1622 (HM), displaying significantly enhanced RLS signals. By measuring the RLS signals characterized at 300.0 nm (I_300.0) and the RLS intensity ratio (I_276.0/I_294.0), respectively, fsDNA over a wide dynamic range of content could be detected. Typically, when HM concentration is kept at 6.0 × 10⁻⁵ mol l⁻¹, using I_300.0 could detect fsDNA over the range of 50-2000 ng ml⁻¹ with the limit of 3.0 ng ml⁻¹, while using I_276.0/I_294.0 could detect fsDNA over the range of 0.5-2500 ng ml⁻¹ with the limit of 0.05 ng ml⁻¹. Thus the latter so-called DW-RLS ratiometry is obviously superior to the former one. Based on the measurements of I_300.0 and I_276.0/I_294.0 data, a Scatchard plot concerning the interaction between HM and fsDNA could be constructed and thus the binding number (n) and binding constant (K) could be available with the values of 13.5 and 1.35 × 10⁵ mol⁻¹ l, and 11.9 and 1.65 × 10⁵ mol⁻¹ l, respectively.     

氢化物发生-原子荧光光谱法测定淡水鱼中砷和汞

应用AFS820双道原子荧光光度计同时测定鱼肉、鱼骨中的砷和汞含量,样品采用湿消解法和干灰化法。结果表明,砷和汞在鱼骨中富集量高于鱼肉。该方法对砷、汞的检出限均小于0.06μg/L,RSD（n=5）：砷〈4.8%、汞〈6.2%,回收率分别为90%—118%和92%—115%。     

鱼粉中掺杂豆粕的可见和近红外反射光谱分析研究

探讨了基于可见和近红外反射光谱分析技术检测鱼粉中是否掺有植物饼粕的可行性。收集了我国常用的鱼粉和豆粕,将豆粕按不同浓度掺杂到鱼粉中制备试验样本,分别进行了定性和定量分析研究。定性分析用206个样本作为校正集,103个样本作为检验集,选择合适的光谱预处理方法和光谱范围建立了定性判别分析模型,模型对外部检验集的正确判断率为96.12％。定量分析用掺杂有豆粕的130个鱼粉样本作为校正集,65个鱼粉样本作为检验集,采用偏最小二乘法(PLS)建立了定量分析模型。以变量标准化处理(SNV)与二阶导数(2, 4, 4, 1)相结合处理效果最佳,其预测值和测量值的决定系数R2和标准差SEC分别为0.989 0和1.539 0;检验集进行外部验证的决定系数R2和标准差SEP分别为0.988 8和1.786 0,RPD为8.61。结果表明,利用近红外光谱分析技术可以成功检测鱼粉中豆粕的存在和含量。