X射线荧光光谱法分析镁砂的主次成分

采用镁砂标准样品作为校准样品,建立了熔融制样X射线荧光光谱法测定镁砂中MgO,Al2O3,SiO2,CaO,P2O5,Fe2O3的方法。采用熔融法为样品片和校准片的制备方法,选择四硼酸锂-偏硼酸锂（67＋33）为助熔剂,1.00mL LiBr溶液为脱模剂,熔融温度为1 100℃,熔融时间20min。对镁砂样品测定的相对标准偏差（RSD）小于3%,对不同镁砂标准样品进行测定,方法的测定结果与认证值相吻合。     

X射线荧光光谱法分析镁砂中的主次成分

采用镁砂标准样品作为校准样品,建立了熔融制样X射线荧光光谱法测定镁砂中MgO,Al2O3,SiO2,CaO,P2O5,Fe2O3的方法。采用熔融法为样品片和校准片的制备方法,选择四硼酸锂-偏硼酸锂(67+33)为助熔剂,1.00mL LiBr溶液为脱模剂,熔融温度为1 100℃,熔融时间20min。对镁砂样品测定的相对标准偏差(RSD)小于3%,对不同镁砂标准样品进行测定,方法的测定结果与认证值相吻合。     

电感耦合等离子体原子发射光谱法测定铬矿石中硅、铝、镁、铁

采用过氧化钠和氢氧化钠高温熔融铬矿石样品,以盐酸溶解熔块,合并溶液后用电感耦合等离子体原子发射光谱法测定样品中硅、铝、镁和铁的含量。选择212.412,308.215,285.213,238.204 nm分别作为硅、铝、镁、铁的分析谱线。用铬矿石标准样品配制标准溶液,对标准溶液的贮存方法进行了研究,对影响标准曲线稳定性的因素进行了讨论。SiO2、Fe2O3、Al2O3和MgO的线性范围依次为0.61%～14.64%,13.62%～27.74%,9.29%～15.17%和9.87%～21.49%。采用该法对铬矿石样品进行30d的连续测定,SiO2、Fe2O3、Al2O3和MgO测定值的相对标准偏差分别在0.51%～1.3%,0.45%～2.0%,0.50%～2.5%和1.4%～2.3%之间。     

碱熔-电感耦合等离子体原子发射光谱(ICP-AES)-内标法测定水泥标准物质中的氧化物含量

电感耦合等离子体原子发射光谱(ICP-AES)法与内标法的结合扩展了ICP-AES的分析范围。采用氢氧化钠熔融样品，ICP-AES-内标法测定各类水泥标准物质样品中SiO2、Al2O3、TFe2O3、MgO、TiO2等氧化物的含量。实验结果表明，标准物质测定值与标准值吻合，6次平行样品测定相对标准偏差小于1.4%。方法一次熔样，纵向测定主常量元素，操作简单，快速，准确，为水泥标准物质的研制提供了另一种定值方式。     

碱熔-标准物质法-电感耦合等离子体发射光谱(ICP-AES)法测定硅酸盐岩中10种主量元素

硅酸盐岩元素的准确测定是其地球化学分析研究的基础,其主量元素含量通常可以采用电感耦合等离子体发射光谱(ICP-AES)法测定,但其测定方法的系统性研究相对缺乏,尤其是样品前处理和基体干扰的有效消除两方面。前处理过程中,考察不同熔剂用量对硅酸盐岩样品的分解能力,发现当熔剂与样品比例达到6:1后,熔珠为纯色透明,经稀硝酸提取后溶液澄清,确定了硅酸盐岩前处理时熔剂与样品的最佳配比。测定过程中,通过考察基体匹配法和标准物质法两种基体干扰消除方法对测定结果的影响,发现当采用与岩性一致或者接近的标准物质绘制校准工作曲线时,基体干扰消除效果更好,更适用于测定硅酸盐岩10种主量元素含量。据此,建立了硅酸盐岩经偏硼酸锂熔融,稀硝酸振荡提取处理,以标准物质法绘制校准工作曲线,采用ICP-AES法同时测定SiO2、Fe2O3、Al2O3、CaO、K2O、MgO、Na2O、TiO2、P2O5、MnO 10种成分含量的方法。对岩石标准物质GBW07107进行分析测定,方法的相对标准偏差(RSD)为0.17%～0.75%,方法检出限为0.001%~0.016%,满足硅酸盐岩样品元素定量分析的要求,而且操作简单快速,环境污染小,适用于大批量样品分析。     

熔融制样-X射线荧光光谱法测定地质样品中的主次成分

以Li2B4O7,Li BO2和Li F(质量比为45:10:5)为混合熔剂,NH4NO3为氧化剂,Li Br为脱模剂,熔融制作样片,利用岛津1800型X射线荧光光谱分析仪,对土壤、水系沉积物、硅酸盐、白云岩等标准物质拟合校准曲线,建立了X射线荧光光谱法(XRF)同时测定岩石、土壤样品中主次量组分(Si O2,Al2O3,TFe2O3,Mg O,Ca O,K2O,Na2O,M n O,Ti O2,P2O5,Zn O)的快速分析方法。对样品制备以及分析测试过程中的条件(熔剂稀释比例、熔融温度及时间、测定电压电流以及脉冲高度分析)进行了优化,在优化的条件下,对GBW07105,GBW07401进行重复测定,相对标准偏差RSD2%,相对误差RE5%。同时对超基性岩、硅酸盐、沉积物、土壤等国家标准样品进行分析,结果与标准参考值有良好的一致性。     

熔融制样-X射线荧光光谱法测定锆钛矿中主次成分

锆钛矿是一种稀缺资源,也是一种战略性矿产,准确分析锆、钛及其共伴生有用有害元素含量对综合评价锆钛矿资源具有重要意义。本文采用稀释比1:20的四硼酸锂-偏硼酸锂混合熔剂,先700℃预氧化7min,再1050℃熔融19min制样,建立了熔融制样-X射线荧光光谱法测定锆钛矿中SiO2、Al2O3、Fe2O3、CaO、MgO、MnO、TiO2、K2O、Na2O、P2O5、ZrO211种主次成分的分析方法。该方法解决了锆钛矿石前处理过程中锆钛易水解,分析周期长的问题。采用标准样品加入光谱纯的方式配制锆钛矿的标准系列样品解决锆钛矿石标准样品不足的问题。本方法各组分的检出限在0.004~0.13%之间,各组分测定结果的相对标准偏差(RSD,n=12)在0.060~2.6%之间。采用本方法对实际样品进行测定,测定值与传统方法测定值一致,并具有操作简便,分析周期短的优点。     

X射线荧光光谱法测定钠冰晶石的主要化学成分

选用国家标准样品和高纯物质配制实验用标准样品,采用混合熔剂(67%Li2B4O7+33%LiBO2)熔融制样,使用X射线荧光光谱法测定钠冰晶石中SiO2、Fe2O3、MgO、CaO、K2O、TiO2、P2O5、Na、F、Al各组分的含量,实验结果表明,各组分的相对标准偏差(RSD)在0.57%~6.5%,与第三方实验室对比测定结果表明,方法可以满足工厂检测要求。     

X射线荧光光谱法测定硅石中主次量元素组分

以Li_2B_4O_7、LiBO_2和LiF(质量比为45∶10∶5)为混合熔剂,NH_4NO_3为氧化剂,LiBr为脱模剂,熔融制作样片,采用硅质砂岩、石英岩标准样品和配制标准样品作为校准样品,建立了熔融制样-X射线荧光光谱法(XRF)测定硅石中主次量成分(SiO_2、Al_2O_3、TFe_2O_3、MgO、CaO、K_2O、MnO、TiO_2、P_2O_5)的快速分析方法。对样品制备以及分析测试过程中的条件进行了优化,在最优条件下,对标准样品(GBW03112、GBW07835)进行重复测定,相对标准偏差RSD2%。同时对3个混合配制的硅石标准样品进行分析,结果与参考值无显著性差异。     

膜去溶-ICP-MS法测定高纯Eu_2O_3中14种痕量稀土杂质

研究了不需基体分离,膜去溶-ICP-MS法直接测定高纯Eu2O3中的14种痕量稀土杂质的分析方法。讨论了Eu基体产生的多原子离子对被测元素的质谱干扰。使用膜去溶后,待测元素灵敏度提高3倍左右,EuO/Eu产率从去溶前的0.016%降低为0.0007%。建立了Tm的数学校正方程,通过膜去溶结合数学校正可将Eu基体对Tm干扰完全消除。14种稀土杂质的检出限和(∑RE)为70 ng/L,测定下限和(∑RE)为0.54μg/g。对6N高纯Eu2O3样品进行了分析,样品回收率为96%~109%,RSD小于10%。所建立的方法对Eu2O3标准样品的测定结果与国家标准方法测定结果相一致。     

自行配制的系列标准样品应用于刚玉质耐火材料的X射线荧光光谱分析

用矾土标准物质、白云石标准样品、基准氧化铝及优级纯氯化钾和氯化钠作为基本材料,并应用Excel公式算法求得上述各物质的准确质量,配制成一组包括各被测组分的质量分数呈梯度分布的12种混合物,分别将上述各混合物置于铂-金坩埚中与无水四硼酸锂熔融,所得玻璃状熔块即为自制的一组供X射线荧光光谱分析刚玉质耐火材料用的系列标准样品。按所给的各分析通道的参数,测定了此类耐火材料中8项组分(即SiO2、Al2O3、MgO、Na2O、K2O、Fe2O3、CaO及TiO2)。另取基准氧化铝一份,按试验方法作空白试验,从而消除其中可能存在的痕量杂质的干扰。将所配制的系列标准样品应用于实样分析,所得8项组分的测定结果与用化学分析法所测得结果相符,其测定值的相对标准偏差(n=10)均小于12%。     

纳米负载型V_2O_5-WO_3/TiO_2催化剂碱中毒及再生研究

实验制备了陶瓷颗粒为骨架的纳米级V2O5-WO3/TiO2(C)催化剂。采用浸渍法模拟碱金属中毒,研究了中毒及再生对催化剂脱硝活性的影响,运用XRD、FT-IR、H2-TPR、XPS技术表征分析了碱金属对催化剂的失活作用。实验表明,碱金属能使催化剂活性降低,钾的毒性大于钠。FT-IR结果显示,催化剂以Lewis酸作为活性酸位。H2-TPR、XPS结果表明,钾的加入降低了催化剂的氧化能力,主要影响了催化剂表面的吸附氧。采用单纯的水洗方法并不能提高催化剂活性,而酸洗再生后催化剂在较高反应温度下活性得到较好的恢复。     

X射线荧光光谱法测定氧化铝中杂质元素

应用X-射线荧光光谱法测定了氧化铝中11种杂质成分（SiO2，Fe2O3，Na2O，K2O，CaO，TiO2，P2O5，ZnO，V2O5，Ga2O3，Cr2O3）。试样用四硼酸锂和偏硼酸锂作混合熔剂融熔制成玻璃状片形熔块。通过在高纯氧化铝中加入一定量的上述11种元素的纯氧化物配制成中间标准样品，并用此中间标准样品和纯氧化铝作为空白试样组成高、低标，制备了校正曲线。又用此中间标准样品与纯氧化铝按一定比例配制控制样品对分析过程进行质量控制。对所提出方法的精密度进行了考核，结果表明以上11种杂质成分测定结果的RSD值均小于10％。用4种标样对此方法的准确度进行验证，结果表明所得测定值与已知值之间的误差均符合标准规定。     

Atomic-absorption spectrometric determination of calcium, magnesium and potassium in leaf samples after decomposition with molten sodium hydroxide

The decomposition of standard leaf samples of varied origin and nature by fusion with sodium hydroxide in an open system has been studied. The use of sodium nitrate as an auxiliary agent facilitated the mineralization of most of the samples. The solutions obtained were analysed for calcium, magnesium and potassium by flame atomic-absorption spectrometry. The method is fast and quite precise, with absolute standard deviations of 0.04-0.13, 0.002-0.03 and 0.04-0.12% for calcium, magnesium and potassium contents of O.8-5.0, 0.13-0.48 and 0.36-2.2% respectively. The limits of detection (mug/ml) in the determination step were 0.10 for calcium, 0.011 for magnesium, and 0.09 for potassium.     

The use of microemulsion for determination of sodium and potassium in biodiesel by flame atomic absorption spectrometry

A new method for F AAS determination of sodium and potassium in biodiesel using water-in-oil microemulsion as sample preparation is proposed. The method was investigated for biodiesel produced from different sources, as soybean, castor and sunflower oil and animal fat and was also applied for vegetable oils. The optimized condition for microemulsion formation was 57.6% (w/w) of n-pentanol, 20% (w/w) of biodiesel or vegetable oil, 14.4% (w/w) of Triton X-100 and 8% (w/w) of water (aqueous standard of KCl or NaCl in/or diluted HNO₃). The optimized instrumental parameters were: aspiration rate of 2 mL min⁻¹ and the flame composition of 0.131 of C₂H₂/air ratio. For comparison purpose, the determination of sodium and potassium were also carried out according to European norms (EN 14108 and EN 14109, respectively). These norms are applied for determination of sodium and potassium in fatty acid methylic ester samples and consist in the sample dilution using organic solvent and determination by F AAS. The stability of microemulsified aqueous standards and samples was investigated and it was found to be stable for at least 3 days while the organic standard diluted with xylene showed a decrease around of 15% in the analytical signal in 1 h. The limits of detection were 0.1 μg g⁻¹ and 0.06 μg g⁻¹ and the obtained characteristic concentrations were 25 μg L⁻¹ and 28 μg L⁻¹ for sodium and potassium, respectively. The proposed method presented two times better limits of detection and better precision (0.4–1.0%) when compared with the dilution technique (1.5–4.5%). The accuracy of the method was evaluated through recovery tests and comparison with the results obtained by dilution technique. The recoveries ranged from 95% to 115% for biodiesel and 90% to 115% for vegetable oil samples. Comparison between the results obtained for biodiesel by both methods showed no significant differences at the 95% confidence level according to a Student's t-test. This study shows that the proposed method based on microemulsion as sample preparation can be applied as an efficient alternative for sodium and potassium determination in biodiesel samples.     

Mn_xCo_(3-x)O_4复合氧化物及改性催化剂催化分解N_2O

用共沉淀法制备了一组不同组成的MnxCo3-xO4尖晶石型复合氧化物,表面负载碱金属助剂制备改性催化剂,用于催化分解N2O.用X射线衍射(XRD)、N2物理吸附(BET)、红外光谱(FTIR)、扫描电镜(SEM)、H2程序升温还原(H2-TPR)、X射线光电子能谱(XPS)等技术表征催化剂结构.考察了复合氧化物组成、碱金属助剂类型、钾前驱物等制备参数对催化剂结构和催化活性的影响.结果表明:添加助剂K、Cs降低了催化剂表面Co、Mn元素的电子结合能,弱化了Co—O和Mn—O键,有利于氧物种的脱除,提高了催化剂活性.优化出了活性较高的催化剂K/Mn0.4Co2.6O4(K2CO3),有氧无水、有氧有水气氛400℃连续反应50 h,N2O转化率分别保持100%和74.2%,催化剂稳定性较高.     

Slurry sampling ETAAS determination of sodium impurities in optical crystals of potassium titanyl phosphate and potassium gadolinium tungstate

Slurry sampling ETAAS was successfully applied to the determination of sodium impurities in single crystals of potassium titanyl phosphate (KTP) and potassium gadolinium tungstate (KGW). Platform atomizers coated with titanium carbide or tungsten carbide, respectively, were used in order to avoid sensitivity drift due to the changes in the composition and the structure of the platform surface. Calibration curves with aqueous standards could be used for the KGW slurry (no matrix effects); analysis of KTP slurry required the standard additions method. The precision of the proposed method was better than 3% R.S.D. The results obtained by the present method showed a good agreement with those obtained by an independent method-flame AAS after sample digestion, which is an evidence for the good accuracy of the proposed method.     

Aqueous fluoride and the preparation of [99mTc(CO)3(OH2)3]+ and 99mTc-carborane complexes

A method for the preparation of eta5-metallocarborane complexes of technetium-99m in water was developed. The key to the procedure is the use of aqueous sodium or potassium fluoride, which prevents premature degradation of the Tc(I) starting material used to prepare the carborane complexes. Solid-phase extraction was used to purify Tc-metallocarboranes derived from both ortho and meta isomers, which were isolated in good to excellent yields in high radiochemical purities. In conjunction with these studies, a series of fluoride-based "kits" were developed to produce the key precursor [99mTc(CO)3(H2O)3]+ in the absence of any other stabilizing ligand. Using this approach, [99mTc(CO)3(H2O)3]+ could be prepared directly from 99mTcO4- under a range of pH values, including neutral pH, which affords the opportunity to develop one-pot labeling procedures for base-sensitive targeting vectors.     

Rapid high-performance liquid chromatography method for the analysis of sodium benzoate and potassium sorbate in foods

A rapid and reliable method is presented for the determination of the preservatives sodium benzoate and potassium sorbate in fruit juices, sodas, soy sauce, ketchup, peanut butter, cream cheese, and other foods. The procedure utilizes high-performance liquid chromatography (HPLC) followed by UV diode array detection for identification and quantitation of the two preservatives. Liquid samples were prepared by diluting 1 ml of the sample with 10 ml of an acetonitrile/ammonium acetate buffer solution. Samples of viscous or solid foods were prepared by blending the sample with the same buffer solution in a 1:5 ratio followed by a dilution identical to liquid samples. All samples were filtered to remove particulate matter prior to analysis. The HPLC determination of the preservatives was performed using a reversed-phase C18 column and UV detection at 225 nm for sodium benzoate and 255 nm potassium sorbate. The percentage of preservative in the sample was calculated by external standard using authentic sodium benzoate and potassium sorbate. Apple juice, apple sauce, soy sauce, and peanut butter, spiked at 0.10 and 0.050% for both sodium benzoate and potassium sorbate, yielded recoveries ranging from 82 to 96%. The method can detect 0.0010% (10 mg/l) of either preservative in a juice matrix.     

Ion-Selective Electrode Determination of Sodium and Potassium in Blood and Urine

Abstract

The Beckman Electrolyte 2 Analyzer (E2A) has been studied for its response to sodium and potassium content in various laboratory prepared pH-adjusted mixtures of metal chlorides in the absence and presence of albumin and α-, β-and γ -globulins. These mixtures also included MITS, a Mock Ionic Test Serm, containing sodium chloride (15OmM), potassium chloride (4mM), calcium chloride (1mM) and magnesium chloride (1mM). Results for sodium and potassium are often low for these non-clinical standards.

Responses have also been studied for patient blood serum and urine samples. Some comparisons have been made with data obtained by flame photometry. The blood serum data obtained with the Electrolyte 2 Analyzer are statistically compared with those obtained by flame photometry.