超声波-酸浸-火焰原子吸收光谱法测定烟叶中微量钙和镁

盐酸为浸提剂,超声波提取空气-乙炔火焰原子吸收光谱法测定烟叶样品中的微量钙、镁。与干法、湿法处理样品进行对照实验,三者间无显著性差异,超声波-酸浸法处理的精密度和回收率略优;测定了国家烟草标准样品GBW08514和GBW08515中钙、镁的含量,其结果与标准值相符;检测了9个2003年度湖南烟叶中的Ca、Mg含量,钙的校准曲线线性范围为0.0-5.0mg/L,线性相关系数是1.0000,方法检出限为0.1602mg/L,回收率为98.9%-101.5%,相对标准偏差≤0.28%;镁的校准曲线线性范围为0.0-0.8mg/L,线性相关系数为0.9992,检出限为0.0039mg/L,回收率为98.5%-102.6%,相对标准偏差≤0.36%;此法快速、安全,适合烟叶中钙、镁的快速检测。     

火焰原子吸收光谱法测定饲料中钙

建立了直接利用测定饲料中磷的样品分解液 ,采用火焰原子吸收分光光度法测定饲料中钙的分析方法。在吸收波长 4 2 2 .7nm处 ,Ca2 + 在 0— 15μg/ m L范围内符合比耳定律 ,回归方程为 A=0 .0 6 44C+0 .0 0 6 3,相关系数 r=0 .9996 ;以 3SA/ S计 ,检出限为 0 .0 5μg/ m L;RSD<3%。加标回收率在 98%— 111%之间 ,应用统计学 F检验法验证方法准确度 ,表明本法和国标法相比无显著差异。方法用于饲料中钙的测定 ,简便、快捷、准确。     

分光光度法测定铋系超导材料中钙

在pH=10.6的NH3-NH4Cl缓冲溶液中,钙离子和酸性铬蓝K显色,于498nm波长处以试剂空白作参比,测定该显色液的吸光度。建立了铋系超导前驱粉(Bi2Sr2Ca2Cu3Ox)中直接测定钙含量的方法。试样中大量存在的锶不干扰测定,用柠檬酸溶液作掩蔽剂,消除了铜的干扰。ε=9.0×103L·mol-1·cm-1,Ca在0—50μg·25mL-1范围内吸光度和浓度有良好的线性关系,回归系数r=0.9994。对合成样品进行6次测定,相对误差为-0.93%。对两种实际样品分别进行6次测定,RSD分别为1.63%和1.19%。     

共振光散射法测定三聚氰胺

应用共振散射光谱技术建立三聚氰胺检测新方法。三聚氰胺可使甲醇体系在567nm处的共振散射光明显增强。在优化实验条件下,体系的ΔI值与三聚氰胺的浓度在0.7—16.0mg/L之间具有良好的线性关系,线性方程为ΔIRLS=40.53C(mg/L)-2.64,r=0.9993;检出限为0.21mg/L;样品加标回收率为92.6%—102.3%。方法灵敏,操作简便,分析成本低,用于奶粉中三聚氰胺的测定,结果满意。     

四溴荧光黄反射散射光度法测定血清白蛋白

在pH=3.0的B-R缓冲介质中,人血清白蛋白(HSA)与四溴荧光黄(TBF)结合,形成TBF-HSA复合物并被石蜡微晶吸萃,以试剂空白参比,在555nm处产生一灵敏的反射散射吸收峰。HSA的浓度在0.0—1.2mg/L范围内与555nm处的反射散射吸收值呈良好的线性关系。方法对HSA的检出限为0.058mg/L,本方法灵敏,可用于人血清样品中蛋白质的测定。     

原子吸收光谱法测定硫酸盐型卤水中钙

加入BaCl2消除SO_4~(2-)的干扰,原子吸收光谱法测定硫酸盐型卤水中的钙。方法检出限为4.8mg/L(稀释100倍样品)。回收率为96%—98%。RSD(n=12)=1.6%,方法操作简单、灵敏度高、实用性强。     

火焰原子吸收光谱法测定粤东第一温泉中钾、钠、钙、锰和锌

用火焰原子吸收光谱法测定粤东第一温泉源头水中的钾、钠、钙、锰和锌。测定结果为 :钾 2 .5 5 4mg/ L、钠 2 4 2 .0 mg/ L、钙 74 .4 0 mg/ L、锰 1 .0 78mg/ L、锌 0 .96 0 0 mg/ L,RSD1 .2 1 %— 2 .5 6 %,回收率 98.3%— 1 0 1 .1 %。     

钙黄绿素-Pd2+荧光光度法测定甲基对硫磷

报道了甲基对硫磷的荧光光度测定方法.在pH=7.4的缓冲溶液中钙黄绿素有荧光,Pd2+与其反应使其荧光消失.由于甲基对硫磷与Pd2+形成的配合物比钙黄绿素-钯配合物更稳定,加入后可使钙黄绿素游离出来而重显荧光,激发波长和发射波长分别位于492nm和512nm,测得游离的钙黄绿素荧光强度与甲基对硫磷浓度在1.0×10-7-1.2×10-6mol/L范围内呈良好的线性关系,检出限为5×10-8mol/L,空白样品加标回收率为87%-108%,相对标准偏差小于4%.     

珍珠明目滴眼液中微量钙的共沉淀分离原子吸收光谱分析

采用硝酸锶-碳酸钾共沉淀分离富集珍珠明目滴眼液中的微量钙,用原子吸收分光光度法测定其含量。进样溶液钙浓度在0.0～20.0μg·mL-1范围内与其422.7 nm处的吸光度成良好线性关系,检出限为0.06 μg·mL-1。该法用于珍珠明目滴眼液中钙的测定,具有灵敏、简便、快速、准确、重复性好,平均回收率为97.0%～98.3%,相对标准偏差RSD为0.4%。     

钙长石质玉中钙铬榴石的谱学研究

所研究钙长石质玉中的绿色矿物是以钙铬榴石为主的石榴石,钙铬榴石在天然条件下非常稀有,颜色为翠绿色,品质高的钙铬榴石可与翡翠、祖母绿相媲美。前人对石榴石系列的其他端元矿物具有较为充分的研究,但对钙铬榴石的研究较少,且未见对钙长石质玉中钙铬榴石光谱特征的相关报道。使用JXA-8230电子探针确定样品石榴石平均组分为Uvt_49.66Grs_36.04Adr_13.58Pr_p0.67Sps_0.06,为以钙铬榴石为主的钙系石榴石。经Bruker Senterra R200L拉曼光谱仪测定样品拉曼位移为1 000,890,879,830,618,589,530,508,399,370,270,240和176 cm-1,受不同三价阳离子Cr3+,Al3+和Fe3+替代的相互影响而发生相应的偏移;用Bruker Vertex80红外光谱仪测定样品红外振动频率为1 019,951,908,844,826,721,669,608,538,496,462,430和413 cm-1,受不同组分晶胞体积及三价阳离子的质量分数影响,发生规律性振动偏移;通过Jasco MSV-5200显微紫外-可见光谱仪及近红外分光光度计测定样品,可见区Cr3+宽吸收带为439和613nm,存在453和685 nm吸收肩峰,同时可见Fe3+ 371 nm吸收肩峰,钙铬榴石主要致色离子为Cr3+。钙长石质玉中钙铬榴石的详细谱学研究为稀有钙铬榴石矿物的鉴定提供了丰富的谱学数据,为相似品独山玉进行区分奠定基础。     

火焰原子吸收法测定高纯饱和氯化钠溶液中的微量Ca和Mg

建立了先用４０１型螯合树脂分离饱和氯化钠溶液中Ｃａ和Ｍｇ再用火焰原子吸收法测定Ｃａ和Ｍｇ的方法。采用优化法研究了从基体预先分离Ｃａ和Ｍｇ的操作条件,本法的相对标准偏差分别为６．５％和５．５％,回收率分别为９９％和９４％。     

Setting reaction of new bioceramic root canal sealers

Objective: This study aimed to evaluate setting reaction and the time of three bioceramics (Endosequence, iRoot-SP, and Smartpastebio) compared with glass ionomer (ActiV-GP) root canal sealers.

Materials and methods: Setting reaction was tested using Fourier Transform Infrared Spectroscopy and X-ray Diffraction; setting time was measured using a Vicat needle.

Results: Three-bioceramic sealers composed of calcium hydroxide, calcium phosphate, calcium silicate, silicon oxide, and zirconium oxide. During their setting, calcite and calcium phosphate silicate were detected. Their setting took longer time than ActiV-GP that have aluminum polyacrylate and calcium phosphate silicate in set mass.

Conclusions: Bioceramic sealers took longer time to set than expected.     

Spectroscopy of calcium deposited on large argon clusters

Spectroscopic experiments have been performed, providing emission and excitation spectra of calcium atoms trapped on argon clusters of average size 2 000. The two experimental spectra fall in the vicinity of the calcium resonance line ¹P ₁ → ¹S₀ at 422.9 nm. The excitation spectrum consists in two bands located on each side of the resonance line of the free calcium. In addition, Monte Carlo calculations, coupled to Diatomics-In-Molecule potentials are employed to simulate the absorption spectrum of a single calcium atom in the environment of a large argon cluster of average size 300. The theoretical absorption spectrum confirms the existence of two bands, and shows that these bands are characteristic of a calcium atom located at the surface of the argon cluster and correspond to the excited 4p orbital of calcium either perpendicular or parallel to the cluster surface. The precise comparison between the shape of the absorption spectrum and that of the fluorescence excitation spectrum shows different intensity ratios. This could suggest the existence of a non adiabatic energy transfer that quenches partly the fluorescence of trapped calcium. Another explanation, although less likely, could be a substantial dependence of the calcium oscillator strength according to the alignment of the calcium excited orbital with respect to the cluster surface. The emission spectrum always shows a band in the red of the resonance line which is assigned to the emission of calcium remaining trapped on the cluster. When exciting the blue band of the excitation spectrum, the emission spectrum shows a second, weak, component that is assigned to calcium atoms ejected from the argon clusters, indicating a competition between ejection and solvation. Received 7 May 2002 Published online 1st October 2002 RID="a" ID="a"e-mail: jmm@drecam.saclay.cea.fr RID="b" ID="b"URA 2453 du CNRS RID="c" ID="c"UMR 5626 du CNRS     

负吸光度法测定牛奶中的钙

研究了钙离子与酸性铬蓝K的反应条件,建立了一种负吸光度法测定钙离子的新方法,钙量在0.0-2.4μg/mL范围内与负吸光度呈线性关系,检出限为2.3×10<'-5>g/L,方法应用于牛奶中钙离子的测定,结果满意.     

Emission spectra simulation of calcium plasmas in non-local thermodynamic equilibrium

We use previous high-quality experimental spectra to test the accuracy of atomic data and the validity of the collisional－radiative (CR) model used in this paper. The synthetic spectrum with electron temperature log T_e(K)=6.745 and electron density n_e=6.0×10^{13}cm^{-3}, which almost reproduces the experimental spectra, is presented. Nearly all the features of the experimental spectra were identified. The results of the CR modelling for the emission spectra of calcium plasmas all agree well with the measured spectral line intensities within the experimental error for most of the lines. Furthermore, we make the electron temperature diagnostic through the synthetic spectrum and population fractions of every ionization state as a function of charge state at different electron temperatures, as well as the electron density diagnostic through the intensity ratios of two lines of Be-like calcium and three lines of C-like calcium. A good agreement between the calculated values and the measured ones is found.     

光电光谱法分析钢中钙

本文研究了用光电光谱法测定钢中钙的方法 ,确定了最佳分析条件 ,分析了共存元素的干扰情况。用本方法测定钢中钙 ,具有良好的准确度和精密度 ,结果令人满意。     

光电光谱分析电炉钢中微量Ca

电炉炼钢工艺中对 Ca的成分有一定的要求 ,特别是微量 Ca元素的快速炉前分析。采用仪器所带原始曲线 ,现有的标样 ,以及与 ICP对照比较试样 ,成功地解决了这一 Ca的分析问题。     

Measuring calcium uptake and inositol 1,4,5-trisphosphate-induced calcium release in cerebellum microsomes using Fluo-3

A simple fluorimetric method is presented for measuring calcium uptake and inositol 1,4,5-trisphosphate (InsP₃)-induced calcium release in microsomes using Fluo-3. This method is used to investigate the amplitude of calcium release (quantal release) induced by InsP₃ from rat cerebellum microsomes.     

哺乳动物尿液中钙镁离子浓度的1H NMR测定方法

哺乳动物体液中的钙镁离子浓度能够反映体内营养代谢的平衡与一些疾病的发生发展. 尿液中钙镁离子浓度的准确测量需要不受基质影响的便捷新方法. 该文使用过量乙二胺四乙酸(EDTA)为探针并通过¹H NMR方法测定钙镁离子与EDTA络合物的含量,建立了一种快速原位的尿液钙镁离子浓度测量方法. 将此方法分别用于人、大鼠及小鼠的尿液测定,发现3类哺乳动物的尿液钙镁离子浓度存在显著的物种依赖性和较大的相同物种个体间差异. 上述为生物体液中钙镁离子浓度的快速定量测量提供了便捷方法,也提供了3类哺乳动物尿液钙镁离子浓度的基础数据.