碳质金矿中金的化学物相分析方法改进

为了解决碳质金矿金化学物相分析结果与选矿试验结果不符的问题,基于岩矿鉴定和测试结果对分析流程进行改进。方法改进后测试项目包括裸露金和半裸露金、有机碳石墨包裹金、碳酸盐包裹金、褐铁矿包裹金、黄铁矿包裹金、石英和硅酸盐包裹金6项。有机碳石墨包裹金选用Na_2S_2O_3–CuCl_2–NH_4OH–NH_4Cl体系为浸金剂,取代I_2–NH_4I体系,该体系中金的测定采用铜置换原子吸收法。裸露金半裸露金、有机碳石墨包裹金和黄铁矿包裹金的相和为82.34%,与选矿试验金精矿实际回收率(75.83%)基本吻合。改进后的方法适合碳质金矿金化学物相分析。     

YL—110型流动注射测金装置的研制

研制了一台流动注射测金装置。该装置由一台四道蠕动泵，两支转阀，一支８５３１纤维分离富集柱和有关电路组成一个整体，靠蠕动泵自动输送试样溶液，酸洗液和金洗脱液，使金在Ф×４０ｍｍ的微型纤维柱上富集，由控制电路控制旋转阀切换切换自动完成柱平衡，进样，洗，脱过程，金洗脱液自动送入原子上分光光度计测定金。８５３１纤维是金的良好吸附剂，具有选择性容量大的优点。试样经王水分解后可直接进样测定。该装置与原子吸收分     

YL－110型流动注射测金装置的研制

研制了一台流动注射测金装置。该装置由一台四道蠕动泵、两支旋转阀，一支８５３１纤维分离富集柱和有关电路组成一个整体，靠蠕动泵自动输送试样溶液，酸洗液和金洗脱液，使金在Φ３×４０ｍｍ的微型纤维柱上富集，由控制电路控制旋转阀切换自动完成柱平衡，进样，洗涤，洗脱过程，金洗脱液自动送入原子吸收分光光度计测定金。８５３１纤维是金的良好吸附剂，具有选择性容量大的优点。试样经王水分解后可直接进样测定。该装置与原子吸收分光光度计联用测定金。金的特征浓度可达０．６ｎｇ／ｍＬ每小时可测定４０～６０次。用本装置分析０．１６μｇ／ｍＬ金溶液，ＲＳＤ为０．８％。用于分析化探样品，铜精矿，电解铜等试样中金，得到满意的结果。     

离子交换分离富集原子吸收法测定岩矿中微量金

采用410#呱啶树脂分离富集金,研究了410#呱啶树脂吸附金的介质、解吸剂的种类,优化选择了吸附介质的浓度、解吸液的浓度、解吸时间等条件,建立了410#呱啶树脂分离富集-硫脲解脱用原子吸收法测定金的方法。方法的检出限为0．1μg／g,测定结果的相对标准偏差为1．41％-6．49％（Ft=7）,回收率为97％-107％。     

电感耦合等离子体质谱(ICP-MS)法测定元素活动态中的金

金的元素活动态是用来指示隐伏金矿床的有效方法,将各相态金完全提取、准确定量分析,可以清晰、明显地指示地壳深部金矿床的有效信息.金的元素活动态提取液经过王水处理后,采用泡塑吸附-硫脲解脱的方式将金分离富集,解脱溶液一般采用石墨炉原子吸收光谱(GF-AAS)法测定,该方法效率低、检出限高、精密度差,数据可信度降低.采用电感...     

超声波辅助-活性炭富集-火焰原子吸收光谱法测定岩石矿物中的金

在战略性性矿产资源中,金一直都是极其紧缺且重要的元素。目前岩石矿物测定金使用较广泛的方法主要为火试金重量法、活性炭富集-原子吸收光谱法。然而这两种方法分析步骤都比较繁琐,受环境条件影响大,测样周期长,不适合大批量分析测试任务。本文通过超声波辅助,基于超声空化效应,活性炭在超声空化所产生的局部高温、高压、冲击波、微射流等加强传质作用下,能快速高效地对样品中的金离子进行富集的原理,建立一种独特的活性炭富集方法,改进过滤方式,运用火焰原子吸收光谱仪测定金的新方法。通过对9个金矿石成分标准物质GBW(E)070012a、GBW07807a、GBW07808b、GBW07300a、GBW07809b、GBW07297a、GBW07298a、GBW07299a、GBW07810进行实验对比分析,优化方法中活性炭用量,超声波频次与功率、时间、溶液温度等实验条件。研究确定活性炭用量为0.5g后金的回收率趋于稳定;超声波频次和时间设定为100kHZ,20min不仅测定数据准确且能较大幅度缩短工作时间;溶液温度控制在20℃为宜。在优化条件下,方法验证测定得出金的质量浓度在0~20mg/L范围内校准曲线方程为Abs=0.01958K+0.000642,相关系数（R2）为1.0000,以金矿石标准物质GBW(E)070012a平行测定12次计算得出方法检出限（MDL）为0.02248ug/g;以GBW07807a等8个金矿石标准物质进行精密度和正确度方法实验,相对误差（RE）为0.23%~1.50%,相对标准偏差（RSD）为0.43%~3.65%。与国家标准方法进行比对实验,实验证明新方法满足岩石矿物中金的分析要求。     

化学蒸气发生-电感耦合等离子体原子发射光谱法测定地质样品中痕量金

地质样品经盐酸-硝酸(3+1)混合酸溶解,活性炭分离富集后,于90℃用12g.L-1硼氢化钠溶液(溶于0.5g.L-1氢氧化钠溶液中)作还原剂,用化学蒸气发生-电感耦合等离子体原子发射光谱法测定其中痕量的金。金的质量浓度在1 500μg.L-1以内与其发射强度呈线性关系,方法的检出限(3s)为0.59μg.L-1。方法用于测定2个标准物质(GBW 07289和GBW 07291)中金含量,测定值与认定值相符。     

三辛胺从盐酸介质中萃取金（Ⅲ）

三辛胺(TOA)从盐酸介质中萃取、富集金,已应用于原子吸收光谱法测定金,其高灵敏度及选择性使该方法成为金的十分理想的测定方法。本文考查了TOA从盐酸介质中萃取金(Ⅲ)的机理,试图对金(Ⅲ)的萃取分离及测定提供理论依据。 TOA系Fluka进口分装,使用时按计算量配成所需浓度的CCl_4溶液;HAuCl_4用纯金(99.99%)制备;NaCl为基准试剂;其它试剂均不低于分析纯。水相由HAuCl_4-HCl-NaCl配     

水浴加热密闭溶样石墨炉原子吸收光谱法测定化探样品中的痕量金

以王水、氟化钾、Fe3+溶液为溶剂,对化探样品进行水浴加热分解1.5 h,经泡沫塑料吸附后,于90℃以上硫脲溶液中解吸20 min,然后采用石墨炉原子吸收光谱仪测定其中的金含量。对仪器分析条件进行了优化。金的质量分数在0.1~100.0 ng/g范围内与吸光度呈良好的线性,线性相关系数r2=0.999 3,检出限为0.100 ng/g。该方法对金标准物质测定结果的相对标准偏差为5.96%~9.25%(n=12),对国家一级标准物质进行分析,测定结果与标准值相符合。该方法满足1∶50 000化探样品中痕量金的分析要求。     

电感耦合等离子体原子发射光谱法(ICP-AES)测定金红石中TiO_2的含量

建立了用盐酸-氢氟酸作溶剂,使除金红石以外的其它钛矿物分解,过滤后残渣经过氧化钠熔融,水提取,沉淀过滤分离大量的钠离子及其它元素后,经盐酸溶解,用ICP-AES法测定金红石原矿、中矿、尾矿中TiO2的含量。对测定钛的条件及共存元素的干扰情况进行了研究,加标回收率为99.88%~101.00%;相对标准偏差为0.86%~7.9%。方法简单快速,易于掌握。测定元素的含量范围为0.01%~30%。     

The separation–preconcentration and determination of ultra-trace gold in water and solid samples by dispersive liquid–liquid microextraction using 4-ethyl-1(2-(4-(4-nitrophenyl)piperazin-1-yl)acetyl)thiosemicarbazide) as chelating agent and flame atomic absorption spectrometry

A selective separation and preconcentration method for the determination of gold ions in water and ore samples has been developed using dispersive liquid–liquid microextraction, followed by flame atomic absorption spectrometry. 4-Ethyl-1(2-(4-(4-nitrophenyl)piperazin-1-yl)acetyl)thiosemicarbazide) (NPPTSC) has been used for the first time as new chelating reagent. A mixture of ethanol (dispersive solvent) and carbon tetrachloride (extraction solvent) was used. Some parameters affecting the extraction procedure including the type and volume of the extracting and dispersive solvents, HNO₃ concentration, the chelating agent amount, volume of sample, and foreign ions have optimized. Also, the complex formation between gold ions and the ligand has been investigated in a methanol–water solution (1:1) using UV–visible spectrometry. The spectrophotometric titration data showed that of Au–NPPTSC complex composition was found to be 3:2. After optimizing the instrumental and experimental parameters, we achieved a detection limit of 1.5 µg L^?1, a preconcentration factor of 50, and a linear dynamic range of 10.0–400.0 µg L^?1. The relative standard deviation obtained 2.1% at 50 µg L^?1 for gold ions (n = 10). The proposed method was successfully performed for the determination of gold in certified reference material, environmental water, and ore samples.     

Automated Method for the Selective Determination of Gold by On-Line Solvent Extraction and Reversed Micellar-Mediated Luminol Chemiluminescence Detection

A new method based on the direct coupling of on-line solvent extraction with chemiluminescence (CL) of luminol in reverse micelles is proposed for the determination of gold(III) in a reverse-flow injection system. In the on-line process, gold(III) is extracted from aqueous hydrochloric acid solution with tri-n-octylphosphine oxide in chloroform, followed by separation through a microporous Teflon membrane. A reversed micellar system of cetyltrimethylammonium chloride-water (buffered with sodium carbonate)-6:5 (v/v) chloroform-cyclohexane was used as a medium for the CL reaction. Linear calibration for gold was established over the concentration range 10-5000 ng ml⁻¹ and the detection limit was 1 ng ml⁻¹. Much higher tolerable levels of potential interfering metal ions were achieved for the present on-line procedure. The present method was applied to the analysis of industrial samples of silver-based alloy.     

Cloud point extraction and preconcentration of gold in geological matrices prior to flame atomic absorption determination

Brilliant green was used as a complexing agent in cloud point extraction (CPE) and applied for selective preconcentration of trace amounts of gold in geological matrices. The analyte in the initial aqueous solution was acidified with hydrochloric acid (0.1 M) and octylphenoxypolyethoxyethanol (Triton X-114) was added as a surfactant. After phase separation, based on the cloud point separation of the mixture, the surfactant rich phase was diluted with methanol and the analyte determined in the surfactant rich phase by flame atomic absorption spectrometry (FAAS). After optimization of the complexation and extraction conditions, a preconcentration factor of 31 was obtained for only 10 mL of sample. The analytical curve was linear in the range of 3–1000 ng mL⁻¹ and the limit of detection was 1.5 ng mL⁻¹. The proposed method was applied to the determination of gold in geological samples.     

Determination of mercury in air by means of computerized flow constant-current stripping analysis with a gold fibre electrode

Mercury in air was determined after collection in potassium permanganate or sodium carbonate solution. The mercury concentration in these solutions was determined in a computerized flow potentiometric stripping analyzer with a 10-μm gold fibre working electrode, a glassy carbon reference electrode and a platinum counter electrode. After sample electrolysis for 1–10 min, stripping was done in a 1 mg l^?1 gold(III) solution in 0.01 M nitric acid/0.01 M sodium nitrate with a constant stripping current of 0.50 μA. Results obtained for flue gas samples were in good agreement with results from cold-vapor atomic absorption spectrometry.     

Determination of riboflavin in pharmaceutical products by automatic discrete-sample analysis

A procedure for the determination of iron, copper, nickel, cobalt, manganese and chromium down to 0.01 μg g^-1 in sodium calcium silicate glass, sodium borosilicate glass, sodium carbonate and calcium carbonate is described. The analytical procedure depends on the separation at pH 6 of the metal diethyldithiocarbamates into isobutyl methyl ketone, and their determination by flameless atomic absorption spectrometry, with a Massmann-type graphite furnace. The limiting factors on the detection limits attainable are discussed and related to the purity of the acids used for sample solution, sample contamination during chemical separation and the sensitivity of the analytical technique.     

碱性氯化法破氰-碲共沉淀富集-电感耦合等离子体原子发射光谱法测定氰化退镀液中金含量

采用碱性氯化法氧化分解样品中氰化物,碲共沉淀法分离富集破氰溶液中的金,建立了电感耦合等离子体原子发射光谱法(ICP-AES)测定退镀液中金的分析方法. 在碱性条件下,使用次氯酸钠氧化分解退镀液中的氰化物,使其转化为二氧化碳和氮气,使用亚硫酸钠溶液中和破氰溶液中的余氯,消除氧化物对氰化物测试包的影响,可以简便快速判断退镀溶液破氰效果. 在3.6 mol/L盐酸介质中,12.5 mL碲溶液(2.5 g/L)和11.0 mL氯化亚锡溶液(1 mol/L)可定量沉淀5~500 μg金,50倍量的杂质元素不干扰测定. 金的质量浓度在0.05~25.00 mg/L范围内与其发射强度呈线性,线性回归方程为y=46.487x+0.343,相关系数r大于0.999 9,检出限为0.004 4 mg/L. 对实际样品进行准确度考察,测定结果的相对标准偏差(RSD, n=7)低于1.0%,加标回收率为96.9%~103.1%,实际样品测定结果与火试金法的对照结果一致性好.     

Modified Activated Carbon as Solid Phase Extraction Adsorbent for the Preconcentration and Determination of Trace As(III) in Environmental Samples by Graphite Furnace Atomic Absorption Spectrometry

A simple and selective method was developed for the preconcentration, separation, and determination of trace amounts of As(III) in an aqueous solution by solid phase extraction combined with graphite furnace atomic absorption spectrometry. Activated carbon (AC) was modified by sodium diethyldithiocarbamate (NaDDTC) and then used as a new, stable and easily prepared solid sorbent in a mini column for the extraction of As(III) in aqueous solution. Factors influencing the sorption and desorption of As(III), such as volume and concentration of eluent, sample pH, flow rate and effect of interfering ions on the recovery of As(III) have been systemically investigated. At pH 2.0 As(III) could be adsorbed quantitatively by NaDDTC‐AC, and then eluted completely with 2 mL of 3.0 mol·L^?1 HNO₃. The amount of eluted As(III) was measured using graphite furnace atomic absorption spectrometry. The detection limit of As(III) was 0.04 ng·mL^?1 with enrichment factor of 100 and the relative standard deviation (RSD, n=8) was 1.58% at 10 ng·mL^?1 level.     

Selective determination of ultra trace amounts of gold by graphite furnace atomic absorption spectrometry after dispersive liquid-liquid microextraction

A simple, rapid and sensitive method is proposed for selective determination of ultra trace amounts of gold from different samples. The method is based on highly efficient separation and pre-concentration of gold by dispersive liquid-liquid microextraction of gold followed by its determination with graphite furnace atomic absorption spectrometry. The pre-concentration procedure results in quantitative extraction of gold by victoria blue R from a 10-mL sample into fine droplets of chlorobenzene, with a sedimented volume of 25 microL. Then, 20 microL of 0.04% Pd(NO3)2, as chemical modifier, followed by 10 microL of the sedimented phase were consecutively pipetted into the same auto-sampler device and the content is injected into the graphite tube and the gold content is determined by graphite furnace atomic absorption spectrometry. After optimizing the extraction conditions and instrumental parameters, a pre-concentration factor of about 388 is obtained for the system. The analytical curve is linear in a concentration range of 0.03-0.5 ng mL(-1). The detection limit and relative standard deviation are 0.005 ng mL(-1) and 4.2%, respectively. The method was successfully applied to the extraction and determination of gold in tap water and silicate ore samples.     

Solid phase extraction of gold by sorption on octadecyl silica membrane disks modified with pentathia-15-crown-5 and determination by AAS

A simple and selective method for rapid and efficient concentration and determination of μg l⁻¹ levels of Au(III) ions in aqueous solution using octadecyl silica membrane disks modified by pentathia-15-crown-5 and flame atomic absorption spectrometry is presented. The influence of flow rates of eluent and sample solution, amount of ligand, types and least amount of eluent for elution of Au from disks were investigated. Break through volume and limit of detection of the membrane disks modified by 5 mg of the thiacrown ether was found to be 2.0 l and 1.0 μg l⁻¹, respectively. The effects of various cationic interferences on percent recovery of gold were studied. The method was successfully applied for the determinations of gold in some pharmaceutical samples and for the recovery of trace Au³⁺ ions from synthetic and water samples.     

Electrothermal atomic absorption spectrometry of elements after electrochemical deposition on graphite electrodes

The application of electrochemical deposition on graphite rods for separation and preconcentration prior to electrothermal atomic absorption spectrometry (a.a.s.) is examined. The metals to be determined are electrolyzed onto a graphite rod which is tehn transferred to a cup atomizer for a.a.s. Although only some of the element present in the solution is deposited on the surface of the graphite rod, favorable preconcentration rates are obtained. The method was tested on the determination of cadmium in aqueous solution. The precision is satisfactory for concentrations down to 5 × 10^?8 g l^?1 cadmium, and the detection limit is 4 × 10^?9 g l^?1.