A cathodic stripping voltammetric method for nanomolar concentrations of labile and total iron and zinc in soil solutions

Abstract

Linear sweep cathodic stripping voltammetric methods were modified to measure labile and total concentrations of Fe³⁺ and Zn²⁺ in the nanomolar range in soil solutions. Labile concentrations of Fe (25–220 nmol/L) and Zn (37–208 nmol/L) were measured in 0.5 mL aliquots of filtered (0.4 μm) distilled water extracts (solution:soil ratio= 1) of four agricultural soils. After decomposition of complexed forms of the metals by evaporation of the solutions in HNO₃, total soluble Fe and Zn were measured. Labile Fe comprised approximately 1% of total soluble Fe, while labile Zn comprised 13–43% of total Zn in the four soil solutions. The methods provide a linear range of 5 ‐100 nmol/L and sufficient precision to detect concentrations of labile and total Fe and Zn likely to occur in soil solutions.     

饲料添加剂中微量游离铜的极谱测定

提出在H2O4-EDTA-KNO3-明胶体系中以单扫描极谱测定饲料添加剂中微量游离铜的方法.用硝酸浸取法提取试样中的游离铜.铜的极谱峰电位为-0.2V(相对饱和甘汞电极).铜浓度在0.1～100μg/mL范围内与峰电流呈良好的线性关系.检出限为0.04 μg/mL,RSD为3.3%,加标回收率为97%.该方法简便、快速、测定精度好,可用于实际样品的测定.     

在表面活性剂存在下泰尔登的电分析化学特性研究

在ｐＨ７．００缓冲溶液中，当有０．００２０％ＯＰ存在时，泰尔登在－１．９５Ｖ产生一灵敏极谱波，利用此波可测定痕量泰尔登，检测下限为５．４×１０￣（－９）ｍｏｌ／Ｌ。用恒电位库仑法，计时库仑法和循环伏安法测得反应电子数为２，吸附量为１．１７×１０￣（－１０）ｍｏｌ／ｃｍ￣２，扩散系数为４．３×１００￣（－５）ｃｍ￣２／ｓ。     

微分脉冲催化极谱法测定乳牛全血硒

采用美国２７３Ａ型电化学分析系统，根据ＳｅＳＯ３２－－ＫＩＯ３氧化还原反应原理，用微分脉冲催化极谱法测定了奶牛全血痕量硒。此法最低检出极限０．１μｇ／Ｌ，线性范围０．５～５．０μｇ／Ｌ，回收率９２．６０％～１０３．００％。硒标准溶液和饲料重复测定值的变异系数分别为１．５％和２．２％。奶牛全血硒的测定值符合饲料梯度添加试验，其精密度和准确度均高。     

Multiple use of plants: Studies on selenium incorporation in some agricultural species for the production of organic selenium compounds

The technique of spraying plants with inorganic forms of selenium can be employed for phytochemical production of organic selenium compounds. Fractionation of the plant material makes it possible to produce a highly concentrated and well defined selenium supplement with potential use in animal and human nutrition. The fractionation also gives opportunities to combine production of organic selenium compounds with other products, for example plant fibres. Multiple use of plants can contribute to a more efficient utilization of land area (in comparison to monocultures solely adapted to food production). It also gives the opportunity to develop systems suitable for long term fixation of carbon, as long as the plant material is not reoxidised to carbon dioxide. Plant fibres could provide raw material for the production of paper or building materials in combination with the production of organic selenium compounds preferentially accumulated in another fraction of the processed plant.     

除草剂甲磺隆残留分析的极谱法测定

采用示波极谱法研究了甲磺隆的极谱吸附波及其性质。在0.4mL冰醋酸和0.5mL1mol·L-1醋酸-醋酸钠介质中甲磺隆于-1.20V(vs.SCE)处产生一波形较好的二阶导数极谱波。在此实验条件下,甲磺隆浓度在7.8×10-7～1.30×10-3mol·L-1范围内与导数波峰电流(Ip)呈良好线性关系。检出限为2.60×10-7mol·L-1。本方法用于测定污水模拟体系中甲磺隆的回收率可达95.78%,土壤蔬菜残留的分析测定也较理想。     

蛋白质的电化学特性研究

研究了蛋白质的极谱特性 .在 p H值为 2 .6 6的 B- R缓冲溶液中 ,当有 0 .0 70 mol/ L KCl存在时 ,BSA在 - 1.90 V左右产生一良好的极谱波 ,利用此波可测定微量的 BSA,线性范围为 4 .5× 10 - 8～ 2 .0× 10 - 6mol/ L,检测下限为 2 .7× 10 - 8mol/ L.所提出的方法不经任何预处理可直接测定血清中的蛋白质 .     

Monitoring of the photochemical degradation of metamitron and imidacloprid by micellar electrokinetic chromatography and differential-pulse polarography

The photochemical degradation of metamitron (4-amino-4,5-dihydro-3-methyl-6-phenyl-1,2,4-triazin-5-one) and imidacloprid (1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine) has been investigated by differential-pulse polarography (DPP) and micellar electrokinetic chromatography (MEKC); the degradation pathways of these pesticides were elucidated and their degradation products proposed. The electrochemical study of imidacloprid by DPP at different pH values demonstrated the occurrence of two different reduction processes; at pH 6.8, two peaks at −0.90 V and −1.38 V, respectively, were obtained, which are related to the photochemical reduction processes. The photochemical degradation of imidacloprid caused by sunlight was polarographically monitored and its degradation products elucidated. The polarographic reduction of deaminometamitron (obtained by photochemical reduction of metamitron) yielded two peaks at −0.62 and −1.37 V, which are related to the reduction of the CN bonds. The effect of sunlight on the reduction of metamitron was monitored by DPP, and an increase of the concentration of the degradation products was observed with time. MEKC with UV-visible detection was used to separate the pesticides and the products of their photochemical degradation, which were identified in combination with DPP. © 1999 Society of Chemical Industry     

TNR Detection by Oscillographic Derivative Polarography

The detecting method for low concentration of TNR by derivative polarography was proposed. Quantitative detection was carried out at selected polargraphic peaks,-0.5 V and -0.75 V. The relative standard curve, linear range and detection limit were obtained. Meanwhile, interference and recovery experiments were also studied and experimental conditions were optimum. The results show that this method have a wide linear range and lower detection limit.     

锌(Ⅱ)-邻菲啰啉络合物线扫极谱法测定血清白蛋白的研究

利用线扫极谱法研究了锌(Ⅱ)-邻菲啰啉(Phen)二元络合物与人血清白蛋白(HSA)的相互作用并建立了以Zn(Ⅱ)-Phen二元配合物为电化学探针测定HSA的分析测试方法。在最佳条件下,还原峰电流的降低值与人血清白蛋白的浓度2.0~20.0mg/L范围内呈线性关系,线性回归方程为ΔIp″(nA)=140.3C(mg/L)+1981.06(ni=16,γ=0.996),检测限为1.301mg/L(3σ)。应用该法测定了模拟样品和健康人血清样品中蛋白质的含量,结果令人满意。