金属固体中砷的测定探讨

原子荧光光谱法是一种优良的痕量分要技术，具有分析灵敏度高，干扰少，线性范围宽，可多元素同时分析等特点，己应用于许多领域。本文研究：探讨AFS-930型原子荧光仪测定金属固体中砷的测定。     

L-半胱氨酸预还原氢化物-原子荧光法测定氧化铜中砷

研究了氢化物发生-原子荧光光谱法测定高含量氧化铜中痕量砷的适宜条件,试验了不同酸介质和还原剂对测定砷的影响。在最佳条件下,砷的线性范围为0.1～40μg/L,检出限为0.075μg/L。样品分析结果的相对标准偏差为2.28%(n=11),加标平均回收率为96.4%。     

氢化物原子荧光光度法测定食品添加剂中砷含量的不确定度评定

依照GB 5009.76-2014,选取代表性样品,从标准溶液溯源,探索测定食品添加剂中砷含量的数学模型,对检测过程中引入的不确定度进行了分类和量化,系统全面地评定了各个不确定度分量,并给出了运用该方法检测的不确定度评定结果。     

液相色谱-原子荧光光谱法测定饲料中的无机砷及其他砷形态

建立了饲料中4种砷形态的(即As(Ⅲ)、As(Ⅴ)、MMA、DMA)的液相色谱-原子荧光光谱(LC-AFS)测定方法。利用1%的三氯乙酸提取饲料中的砷化合物,经过液相色谱分离,原子荧光光谱仪测定。该方法前处理条件温和,能防止砷化合物在提取过程中转化而造成的假阳性。饲料中的4种砷形态的加标回收率为90.2%～105.1%,相对标准偏差(RSD)≤5.8%。方法定量限As(Ⅲ):0.007 mg/kg,As(Ⅴ)0.023 mg/kg,MMA:0.010 mg/kg,DMA:0.010 mg/kg。本方法选择性好,能够有效的消除基体干扰。可作为饲料中无机砷检测的确证方法。     

微波消解-原子荧光法测定食品中的砷

目的:建立测定食品中砷的微波消解原子荧光法。方法:采用微波消解处理样品,原子荧光法分析测定。结果:砷标准系列浓度在(0~8.0)ng/ml范围内线性关系良好。本方法检出限为0.11 ng/ml样品中砷回收率为88.0%~93.2%,具有简便、快速、灵敏、准确的特点。结论:本方法测定结果令人满意,具有一定的实用价值。     

原子荧光光谱法测定蔬菜中微量砷

采用混酸消解样品,通过探讨消化剂、盐酸浓度、硼氢化钾浓度对测定砷的影响,优化实验条件建立了氢化物发生原子荧光法测定中蔬菜微量砷的含量。该方法灵敏简便、快速准确。砷的检出限为0.047μg/L,线性范围0～80μg/L:样品分析结果的相对标准偏差为3.78%,回收率为94.8%～105.2%。     

双道原子荧光光度计同时测定食品中砷和铅的方法研究

在食品检测中,砷和铅作为有害元素经常同时被作为食品中的必测卫生指标。按照国标检测,测定砷和铅反应介质不一致,砷和铅同时测定的矛盾一直困扰着人们。而本文通过反复试验,选择合适的条件,就可以同时测定砷和铅．避免了繁杂的重复性操作．节省了测定时间。该方法简便快速、稳定性好、适用性强、结果准确可靠。     

原子荧光法烟叶土壤砷的测定

本文应用原子荧光法测定了福建省不同地区烟叶土壤中的砷,对仪器条件和试剂使用进行研究,得到检出限为0.079μg/L,相对标准偏差1.45%,加标回收率为92%-105%,结果表明该法操作简便,准确度高,精密度好。     

原子荧光法烟叶土壤砷的测定

本文应用原子荧光法测定了福建省不同地区烟叶土壤中的砷,对仪器条件和试剂使用进行研究,得到检出限为0.079μg/L,相对标准偏差1.45%,加标回收率为92%～105%,结果表明该法操作简便,准确度高,精密度好.     

原子荧光法烟叶土壤砷的测定

本文应用原子荧光法测定了福建省不同地区烟叶土壤中的砷,对仪器条件和试剂使用进行研究,得到检出限为0．070μg／L,相对标准偏差1．45％,加标回收率为92％～105％,结果表明该法操作简便,准确度高,精密度好。     

原子荧光法测定生态地球化学调查土壤样品中的砷、汞

研究了原子荧光法测定生态地球化学调查样品中的砷、汞的测量条件。As、Hg方法的检出限分别为0.2mg/kg和0.0042mg/kg。As的相对标准偏差(RSD)为≤4.10%,Hg相对标准偏差(RSD)为≤6.38%,方法的各项指标完全满足生态地球化学调查样品检测的要求。     

Quantifying effects of pH and surface loading on arsenic adsorption on NanoActive alumina using a speciation-based model

Arsenic (As) poses a significant water quality problem and challenge for the environmental engineers and scientists throughout the world. Batch tests were carried out in this study to investigate the adsorption of As(V) on NanoActive alumina. The arsenate adsorption envelopes on NanoActive alumina exhibited broad adsorption maxima when the initial As(V) loading was less than a 50 mg g⁻¹ sorbent. As the initial As(V) loading increased to 50 mg g⁻¹ sorbent, a distinct adsorption maximum was observed at pH 3.2–4.6. FTIR spectra revealed that only monodentate complexes were formed upon the adsorption of arsenate on NanoActive alumina over the entire pH range and arsenic loading conditions examined in this study. A speciation-based adsorption model was developed to describe arsenate adsorption on NanoActive alumina and it could simulate arsenate adsorption very well in a broad pH range of 1–10, and a wide arsenic loading range of 0.5–50 mg g⁻¹ adsorbent. Only four adjustable parameters, including three adsorption constants, were included in this model. This model offers a substantial improvement over existing models in accuracy and simplification in quantifying pH and surface loading effects on arsenic adsorption.     

Study of arsenic(V) adsorption on bone char from aqueous solution

Arsenic is a toxic element and may be found in natural waters as well as in industrial waters. Leaching of arsenic from industrial wastewater into groundwater may cause significant contamination, which requires proper treatment before its use as drinking water. The present study described the removal of As(V) on bone char in batch studies conducted as a function of pH, dosage of adsorbent, and contact time. Kinetics revealed that uptake of As(V) ion by bone char was very rapid in the first 30min and equilibrium time was independent of initial As(V) concentration. And the adsorption process followed a first-order kinetics equation. The arsenic removal was strongly dependent on pH and dosage of adsorbent. Fourier transform infrared spectra of bone char before and after As(V) adsorption demonstrated that Ca-OH functional group plays an important role for As(V) ions removal, and the mechanisms of the removal of As(V) on bone char was complex mechanism where both co-precipitation and ion exchange. The results suggested that bone char can be used effectively for the removal of As(V) ion from aqueous solution.     

Using response surface methodology to assess the effects of iron and spent mushroom substrate on arsenic phytotoxicity in lettuce (Lactuca sativa L.)

The effects of iron (Fe) and spent mushroom substrate (SMS) arsenic (As) phytotoxicity towards lettuce in artificial soils were investigated to separate the adverse soil parameters relating to As toxicity using a response surface methodology. SMS induced the root elongation of lettuce in both control and As-treated soils. However, in phytotoxicity test using a median effective concentration (EC₅₀) of As, Fe and the interaction between both parameters (Fe*SMS) significantly affected EC₅₀, which explained 71% and 23% of the response, respectively. The refined model was as follows: EC₅₀ of As (mg kg⁻¹) = 10.99 + 60.03 × Fe − 10.50 × Fe*SMS. The results confirmed that the soil parameters relating to the As mobility in soils were important factors affecting its toxicity. In conclusion, Fe significantly reduced the As phytotoxicity. However, although SMS enhanced the root elongation, SMS in As-treated soils decreased EC₅₀ of As on the root growth via its interaction with Fe. Despite the limitations of the artificial soils and range of parameters studied, the application of this statistical tool can be considered a powerful and efficient technique for interpretation and prediction of the complicated results caused by the interactions between many factors within the soil environments.     

Effect mechanism of arsenic on the growth of ultrafine tungsten carbide powder

Arsenic element refines W powders significantly during the hydrogen reduction process of tungsten oxide in our previous studies. In this paper, the nanocrystalline WC-As composite powders were prepared by carbonization of nano W-As composite powders and the effects of arsenic on the growth of WC powder were discussed in detail. The prepared samples were characterized by X-ray diffraction, differential scanning calorimetric analysis, scanning electron microscope, transmission electron microscope, X-ray photoelectron spectroscopy and Inductively Coupled Plasma. The results showed that arsenic appropriately raised the initial temperature of carbonization, significantly accelerated carbonization reaction process and shorten the reaction time. Moreover, WC-As composite powders merged and grew up directly without particle expansion and cracking. And the nano WAs₂ particles attached to WC grain boundaries and hindered the growth of WC grain through grain boundary migration. The above two effects resulted in the WC-As composite powders prepared at 1300?°C for 2?h with the average size of about 121?nm in diameter.     

QuEChERS/高效液相色谱测定食品中15种多环芳烃

建立了检测食品中15种多环芳烃(PAHs)的QuEChERS/高效液相色谱分析方法。样品经正己烷超声萃取,浓缩后用乙腈溶解,采用含100 mg PSA和100 mg C18填料粉进行净化。净化后,采用高效液相色谱-荧光检测器进行分析测定。在最优化色谱条件下,15种PAHs在1.0~100μg/L范围内,线性关系良好,方法检出限(S/N=3)为0.1~0.9μg/kg,方法的定量限(S/N=10)为0.3~3.0μg/kg。回收率在65~120%,相对标准偏差(RSD)小于15%。该方法具有数据可靠、简便快速,灵敏度高,适合于食品中多环芳烃的测定。     

Distribution of arsenic in groundwater in the area of Chalkidiki, Northern Greece

An integrate study aiming at the occurrence and distribution of arsenic in groundwater in the area of Chalkidiki, Northern Greece has been carried out. Groundwater samples from public water supply wells and private wells were analysed for arsenic and other quality parameters (T, pH, EC, Ca, Mg, Na, K, Cl, HCO(3), NO(3), SO(4), B, Fe, Mn). Arsenic showed high spatial variation; ranged from 0.001 to 1.840mg/L. Almost 65% of the examined groundwaters exhibit arsenic concentrations higher than the maximum concentration limit of 0.010mg/L, proposed for water intended for human consumption. Correlation analysis and principal component analysis were employed to find out possible relationships among the examined parameters and groundwater samples. Arsenic is highly correlated with potassium, boron, bicarbonate, sodium, manganese and iron suggesting common geogenic origin of these elements and conditions that enhance their mobility. Three groups of groundwater with different physicochemical characteristics were found in the study area: (a) groundwater with extremely high arsenic concentrations (1.6-1.9mg/L) and high temperature (33-42 degrees C) from geothermal wells, (b) groundwater with relatively high arsenic concentrations (>0.050mg/L), lower temperatures and relatively high concentrations of major ions, iron and manganese and, (c) groundwater with low arsenic concentrations that fulfil the proposed limits for dinking water.     

The effect of nanocrystalline magnetite size on arsenic removal

Higher environmental standards have made the removal of arsenic from water an important problem for environmental engineering. Iron oxide is a particularly interesting sorbent to consider for this application. Its magnetic properties allow relatively routine dispersal and recovery of the adsorbent into and from groundwater or industrial processing facilities; in addition, iron oxide has strong and specific interactions with both As(III) and As(V). Finally, this material can be produced with nanoscale dimensions, which enhance both its capacity and removal. The objective of this study is to evaluate the potential arsenic adsorption by nanoscale iron oxides, specifically magnetite (Fe₃O₄) nanoparticles. We focus on the effect of Fe₃O₄ particle size on the adsorption and desorption behavior of As(III) and As(V). The results show that the nanoparticle size has a dramatic effect on the adsorption and desorption of arsenic. As particle size is decreased from 300 to 12 nm the adsorption capacities for both As(III) and As(V) increase nearly 200 times. Interestingly, such an increase is more than expected from simple considerations of surface area and suggests that nanoscale iron oxide materials sorb arsenic through different means than bulk systems. The desorption process, however, exhibits some hysteresis with the effect becoming more pronounced with small nanoparticles. This hysteresis most likely results from a higher arsenic affinity for Fe₃O₄ nanoparticles. This work suggests that Fe₃O₄ nanocrystals and magnetic separations offer a promising method for arsenic removal.     

Effect of contact order on the adsorption of inorganic arsenic species onto hematite in the presence of humic acid

The speciation of aqueous and adsorbed As forms of arsenic (As) is a major environmental concern in the presence of humic acid (HA). The speciation during As adsorption process by the effect of contact order were evaluated in various equilibrated ternary systems consisting of As, HA and hematite. One ternary system was composed of the preequilibrated As(III)- or As(V)-HA complex, with the subsequent addition of hematite ((As-HA)-hematite system), and the other consisted of the preequilibrated HA-hematite, with the addition of As(III) or As(V) (As-(HA-hematite) system). The presence of HA led to a decrease in the As adsorption, opposite to cationic adsorption. The order of the amounts of As adsorption were found to follow as: As(V)-hematite>hematite-(As(V)-HA)>As(V)-(HA-hematite)>As(III)-hematite>hematite-(As(III)-HA)>As(III)-(HA-hematite). Free As(V) and As-HA complex were preferentially adsorbed onto the hematite surface. The immobilization of As can come from adsorbed HA on mineral surfaces, and formation of As-HA complex, following their slow kinetics.     

砷的乳状液膜分离与分光光度测定研究

研究了表面活性剂，液体石蜡，内相反萃剂，油内比和料液中盐酸，ＫＩ浓度等条件对分离，富集砷的影响，确定了兰１１３Ａ－液体石蜡－煤油－ＮａＯＨ液膜体系最佳组成和其它最适实验条件。分离后的砷用ＤＤＴＣ－Ａｇ法测定，多种常见共存离子不影响砷的分离和测定；对实样品用标准加入法测定，回收率９７．６％，相对标准偏差为１５％。