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牡丹皮及种植土壤中重金属元素铅和镉的分析 总被引:2,自引:0,他引:2
测定不同产地牡丹皮及种植土壤中的重金属铅、镉含量,并分析牡丹皮与种植土壤中铅、镉含量的相关性.从安徽和山东产地采样,通过硝酸-过氧化氢-氢氟酸体系进行牡丹皮和种植土壤微波消解,用石墨炉原子吸收光谱法(GFAAS)测定牡丹皮和种植土壤中铅、镉含量.Pb元素在0-60μg/L范围内线性关系良好,回收率为102.35%,精密度RSD为1.6% ;Cd元素在0-4μg/L范围内线性关系良好,回收率为99.85%,精密度RSD为0.7%.不同产地牡丹皮均检出重金属元素铅和镉,铅含量偏低、镉含量偏高;种植土壤中的铅、镉含量比较高,大约是牡丹皮的6-7倍.该方法具有分析速度快、测定结果的精确度和精密度高等特点.种植土壤存在着重金属污染现象,为确保药材质量,保护环境、保护药材种植土壤是非常必要的. 相似文献
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采用微波消解珍珠粉样品,石墨炉原子吸收法测定铅和镉.以磷酸为基体改进剂,可提高灰化温度,消除珍珠粉复杂的基体干扰.结果表明珍珠粉中铅含量偏高.镉含量较低.本方法快速简便、结果准确.符合分析要求. 相似文献
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建立了一种基于电感耦合等离子体质谱法(ICP-MS)测定有机肥中砷、铅、镉、镍和铬等元素的方法。探究了湿法消解和微波消解两种样品前处理方法对有机肥中重金属元素的提取效果。结果表明:微波消解法提取效率较高,方法与国标GB/T23349相比,两种方法测定的结果不存在显著性差异;采用国家水系沉积物标准物GBW07311、GBW07312及土壤标准物GBW07401、GBW07404对方法的准确性和可靠性进行评价,其测定数据与标准值相吻合。方法对砷、铅、镉、镍、铬的检出限分别为0.06、0.009、0.04、0.01、0.02μg/L,加标回收率在95.88%-106.07%之间,精密度(RSD)均小于5%。该方法可快速、准确测定有机肥料中砷、铅、镉、镍和铬含量,为有机肥料中上述元素的检测提供了快速稳定的方法。 相似文献
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用非完全消解处理柞蚕蛹样品,即在80-100℃的低温下用浓硝酸和过氧化氢,直至消化液呈透明淡黄色,再加入乳化剂OP溶解消解过程中所产生的油脂,可获得均匀的样品乳浊液.取适量的乳浊液制成试液,注入石墨炉中,以氘灯扣除背景吸收,石墨炉原子吸收光谱法的快速测定铅和镉.研究了样品处理条件和干扰的消除,测定结果与灰化法一致,相对误差≤士1.7%. 相似文献
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建立了中成药镉残留量的浊点萃取-石墨炉原子吸收光谱法。样品先经消解,再以非离子表面活性剂浊点萃取富集消解液中的镉,石墨炉原子吸收光谱法测定镉含量。本方法检出限可达0.008ng/mL;加标回收率94.0%—108.5%;线性范围为0—10ng/mL(r=0.9995)。结果表明,采用浊点萃取可提高石墨炉原子吸收光谱法测镉的灵敏度、准确性、重复性和抗干扰能力。 相似文献
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David J. Foulis 《Foundations of Physics》2007,37(10):1421-1446
We show how effect algebras arise in physics and how they can be used to tie together the observables, states and symmetries
employed in the study of physical systems. We introduce and study the unifying notion of an effect-observable-state-symmetry-system
(EOSS-system) and give both classical and quantum-mechanical examples of EOSS-systems. 相似文献
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ICP-AES法同时测定螺旋藻中Ca、Mg、P、Fe、Cu、Mn、Zn 总被引:9,自引:2,他引:7
本文研究了干法灰化,盐酸溶解盐类,ICP-AES技术同时测定螺旋藻中Ca、mg、P、Fe、Cu、Mn、Zn的方法,进行了共存离子干扰和谱线干扰试验,对Cu、Mn、Zn进行了AAS法测定对比。方法的相对标准偏差为1.39%-5.02%,标准回收率为95.6%-104.8%。方法快速、准确、可靠。 相似文献
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Wallace Rubin 《Journal of voice》1988,1(4):378-385
Allergic, dietary, chemical, biochemical, stress, and hormonal abnormalities have long been recognized as important factors in both abnormalities of the voice and in the general health of the professional vocalist. In recent years objective methods have become available to evaluate and treat allergic, dietary, and chemical abnormalities and to better understand the effects of stress and hormonal variations. Assessment of allergic disease is efficient and cost effective through the use of in vitro testing techniques combined with skin end point titration. This provides highly specific and objective results and leads to accurate planning of desensitization treatment. This form of treatment can be especially beneficial in the prevention of recurrent laryngitis. An accurate nutritional history provides evidence of food sensitivities that can lead to cyclical allergic-like vocal symptoms that can be prevented with the use of elimination diets and the judicious use of desensitization therapy. An adequate knowledge of the potential effects of chemical sensitivities will assist the patient in the avoidance of provocative chemical exposures. An in depth evaluation of biochemical abnormalities and a specific assessment of the nutritional status must be considered to evaluate the underlying causes of long-standing general health problems that can affect the voice. Likewise, hormonal variations are not only important in their direct effects on the vocal mechanism but in their cyclical effects on the patient's basic biochemical balance. Lastly, stress, which has long been related to problems in professional performance, is only now being fully studied to determine its actual biologic influences and these must be related to the causes of voice disturbances. Understanding all these influences and planning a rational and efficient evaluation of these potential problem areas are imperative in the complete care of the patient with voice abnormalities. 相似文献
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Charles A. Kingsbury Jon Weinhold Jeremy Winter 《Journal of Physical Organic Chemistry》2007,20(3):161-166
Three reactions were studied in the diastereomers of 1‐(benzenesulfonyl)‐2‐nitro‐1‐phenylpropane ( 1A and 1B ) and briefly in related compounds: elimination of the benzenesulfonyl group, epimerization of one diastereomer to the other, and deuterium/hydrogen exchange at the methine group next to nitro in starting material. The two diastereomers showed quite different reactivity. The high melting diasteromer showed rapid elimination and some exchange. The low melting diastereomer (at approximately a half‐life) showed extensive epimerization, and elimination to the alkene, but little exchange. There is little effect of aromatic substituents on reaction course. The situation is complicated by re‐addition of benzenesulfinate to the alkene. The addition reaction was similar to elimination in agreement with the Principle of Microscopic Reversibility expectations. An electron transfer mechanism for addition is calculated to be comparatively favorable. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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Z.-Z. Zhang S.-G. Zhou T. Zou 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,56(3):259-271
In this paper, firstly, we study analytically the topological
features of a family of hierarchical lattices (HLs) from the view
point of complex networks. We derive some basic properties of HLs
controlled by a parameter q: scale-free degree distribution with
exponent γ=2+ln 2/(ln q), null clustering
coefficient, power-law behavior of grid coefficient, exponential
growth of average path length (non-small-world), fractal scaling
with dimension dB=ln (2q)/(ln 2), and disassortativity.
Our results show that scale-free networks are not always
small-world, and support the conjecture that self-similar scale-free
networks are not assortative. Secondly, we define a deterministic
family of graphs called small-world hierarchical lattices (SWHLs).
Our construction preserves the structure of hierarchical lattices,
including its degree distribution, fractal architecture, clustering
coefficient, while the small-world phenomenon arises. Finally, the
dynamical processes of intentional attacks and collective
synchronization are studied and the comparisons between HLs and
Barabási-Albert (BA) networks as well as SWHLs are shown. We
find that the self-similar property of HLs and SWHLs significantly
increases the robustness of such networks against targeted damage on
hubs, as compared to the very vulnerable non fractal BA networks,
and that HLs have poorer synchronizability than their counterparts
SWHLs and BA networks. We show that degree distribution of
scale-free networks does not suffice to characterize their
synchronizability, and that networks with smaller average path
length are not always easier to synchronize. 相似文献
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原子吸收光谱法测定桃叶中K,Mg,Sr,Fe,Cu,Mn和Zn等元素 总被引:2,自引:0,他引:2
本文采用桃叶作标准样品,讨论了湿法消化法与炭化-灰化法两种样品处理方法对测定结果的影响及方法操作效果比较,并进一步讨论了温度对炭化-灰化法的影响情况。由此建立起该法的适宜条件。在此条件下,用原子吸收光谱法测定桃叶及冷杉树枯枝、叶中多种元素。其精密度和准确度均能满足测定要求。 相似文献