Verma Santosh K, Deb Manas K
School of Studies in Chemistry, Pt. Ravishankar Shukla University, Raipur 492 010, Chhattisgarh, India.
J Agric Food Chem. 2007 Oct 17;55(21):8319-24. doi: 10.1021/jf071344c. Epub 2007 Sep 25.
The diffuse reflectance Fourier transform spectroscopic (DRS-FTIR) method, using potassium bromide matrix, has been developed for the one-drop microdetermination of sulfite in beverage samples. The present method is very simple, rapid, and precise for the determination of sulfite. The nanogram level of sulfite determination is based on the selection of a quantitative analytical peak at 495 cm (-1) among the three observed vibrational peaks obtained by diffuse reflectance Fourier transform infrared spectroscopy (DRS-FTIR). As little as a single drop of sample is sufficient for quantitative analysis of sulfite. The limit of detection (LOD) and the limit of quantification (LOQ) of the method are found to be 8 and 40 ng of SO 3 (2-) 0.1 g (-1) of KBr matrix, respectively. The linear range of the method (LR) as well as the LOD based on the concentration of sulfite in the solution are 5-500 and 0.8 microg/mL, respectively. The precision in terms of standard deviation and relative standard deviation value at a level of 100 ng of SO 3 (2-) 0.1 g (-1) of KBr for n = 10 are found to be 2 ng of SO 3 (2-) and 2.3%, respectively. The relative standard deviation ( n = 10) for the determination of sulfite in beverage samples available in the local market was observed to be in the range of 2.4-7.8%. The method is free from interionic effects of foreign species. No sample pretreatment is required in this method. The proposed method avoids the requirement of large numbers and bulk amounts of reagents. The method is well-suited to the need of green chemistry.
采用溴化钾基质的漫反射傅里叶变换光谱法（DRS-FTIR）已被开发用于饮料样品中亚硫酸盐的单滴微量测定。本方法测定亚硫酸盐非常简单、快速且精确。亚硫酸盐的纳克级测定基于在漫反射傅里叶变换红外光谱（DRS-FTIR）获得的三个观察到的振动峰中选择495 cm⁻¹处的定量分析峰。仅一滴样品就足以进行亚硫酸盐的定量分析。该方法的检测限（LOD）和定量限（LOQ）分别为8和40 ng SO₃²⁻/0.1 g KBr基质。基于溶液中亚硫酸盐浓度的方法线性范围（LR）以及LOD分别为5 - 500和0.8 μg/mL。当n = 10时，在100 ng SO₃²⁻/0.1 g KBr水平下，以标准偏差和相对标准偏差值表示的精密度分别为2 ng SO₃²⁻和2.3%。观察到当地市场上可得的饮料样品中亚硫酸盐测定的相对标准偏差（n = 10）在2.4 - 7.8%范围内。该方法不受外来物种的离子间效应影响。此方法无需样品预处理。所提出的方法避免了大量试剂的需求。该方法非常适合绿色化学的需求。
