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《化学与生物工程》2018,(12)
向200mL含1.0mmol·L~(-1)阴离子(PO_4~(3-)、Cl-、CO_3~(2-)、SO_4~(2-))的铅溶液(10mg·L~(-1))中加入5g还原铁粉,230r·min-1振荡一定时间后,采用火焰原子吸收法测定铅离子浓度,考察阴离子对还原铁粉去除水体中铅离子的影响。结果表明,阴离子PO_4~(3-)、Cl-、CO_3~(2-)、SO_4~(2-)都可以促进还原铁粉去除水体中铅离子,其中PO_4~(3-)的促进作用最大,SO_4~(2-)的促进作用最小;在所有添加阴离子体系中,还原铁粉去除水体中铅离子的过程伴随着pH值的上升和Eh值的下降。 相似文献
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电解金属锰中微量铅镉的极谱法连续测定 总被引:1,自引:0,他引:1
在氨基乙酸-氯化铵-盐酸羟胺底液中,Pb(Ⅱ)于-0.55 V(vs,SCE),Cd(Ⅱ)(vs,SCE)于-0.74 V产生一个灵敏的导数极谱波,铅的浓度在0.02~10μg/mL、镉的浓度在0.01~5μg/mL范围内与波高呈线性关系,大量的Mn2+使铅镉的波高下降,通过分离锰后可消除干扰。电解金属锰试样经硝酸分解后,利用高氯酸在加热至冒烟时的强氧化性,将锰离子氧化为MnO2予以分离后,可直接在上述条件下进行测定,铅标准回收率94.80%~102.20%,相对标准偏差0.43%~0.86%;镉标准回收率96.60%~101.80%,相对标准偏差2.37%~4.62%。 相似文献
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建立西洋参中药中重金属铅和镉含量的电化学测定方法,考察市售西洋参药材的重金属铅和镉的含量。采用Bi_2O_3-石墨烯材料修饰玻碳电极,建立了阳极溶出伏安法同时快速测定铅和镉的新方法。在10~190μg/L浓度范围内,Pb~(2+)和Cd~(2+)的溶出峰电流与Pb~(2+)和Cd~(2+)的浓度呈良好线性关系,r=0.9991/r=0.9983,回收率RSD5.00%(n=6);西洋参重金属铅和镉的含量分别为15.19、16.81μg/L。Bi_2O_3-石墨烯材料修饰玻碳电极的阳极溶出伏安法检测重金属铅和镉简便、灵敏,可用于西洋参中铅和镉的检测。 相似文献
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化学修饰碳糊电极对环境水样中微量铅、镉离子的连续电化学测定 总被引:1,自引:0,他引:1
报道了用8-羟基喹啉作碳糊电极的修饰剂,测定环境体系中微量铅、镉离子的电化学方法.该电极在KNO3(pH=4.0)中,用吸附溶出伏安法测定Pb2+、Cd2+,在-0.56V(vs,SCE)和-0.84V处有灵敏溶出峰,峰电流与铅的浓度在(3.0×10-8~4.5×10-6)mol/L的范围内呈良好的线性关系,与镉的浓度在(4.0×10-8~3.5×10-6)mol/L的范围内呈良好的线性关系,该方法用于水样中铅、镉的测定,检出限为3.0×10-9mol/L(Pb2+)和5.0×10-9mol/L(Cd2+). 相似文献
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本文介绍了用石墨炉原子吸收光谱法直接测定搪瓷餐具浸出液中痕量元素锑、铅、镉,并对这三种元素的灰化温度、原子化温度和原子化时间进行了选择试验。结果表明,本方法其有快速、简便、灵敏度高、干扰少等优点。采用本方法测定锑、铅、镉的灵敏度分别为3.3×10~(-11)、1.0×10~(-11)、1.2×10~(-12)克/1%吸收;回收率分别为96~106%、98~110%、98~108%;对于10ppb锑、8ppb铅、2ppb镉的溶液,其相对标准偏差分别为10.6%、4.6%和3.1%。 相似文献
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Saturated very long chain fatty acids (fatty acids with greater than 22 carbon atoms; VLCFA) accumulate in peroxisomal disorders,
but there is little information on their turnover in patients. To determine the suitability of using stable isotope-labeled
VLCFA in patients with these disorders, the metabolism of 22-methyl[23,23,23-2H3]tricosanoic (iso-lignoceric) acid was studied in rats in vivo and in human skin fibroblasts in culture. The deuterated iso-VLCFA was degraded to the corresponding 16- and 18-carbon iso-fatty acids by rats in vivo and by normal human skin fibroblasts in culture, but there was little or no degradation in peroxisome-deficient (Zellweger’s
syndrome) fibroblasts, indicating that its oxidation was peroxisomal. Neither the 14-, 20-, and 22-carbon iso-fatty acids nor the corresponding odd-chain metabolites could be detected. In the rat, the organ containing most of the iso-lignoceric acid, and its breakdown products, was the liver, whereas negligible amounts were detected in the brain, suggesting
that little of the fatty acid crossed the blood-brain barrier. Our data indicate that VLCFA labeled with deuterium at the
ω-position of the carbon chain are suitable derivatives for the in vivo investigation of patients with defects in peroxisomal β-oxidation because they are metabolized by the same pathways as the
corresponding n-VLCFA. Moreover, as iso-VLCFA and their β-oxidation products are readily separated from the corresponding n-fatty acids by normal chromatographic procedures, the turnover of VLCFA can be more precisely measured.
A preliminary report of part of this work (Reference 18) was presented at the 5th International Symposium on the Synthesis
and Applications of Isotopes and Isotopically Labelled Compounds, Strasbourg, France, June 20–24, 1994. 相似文献
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高效液相色谱法分析化妆品中微量成分的研究进展 总被引:1,自引:0,他引:1
综述了高效液相色谱法在化妆品中防腐剂、防晒剂中紫外线吸收剂以及性激素的检测等几个方面的应用;同时,介绍了分析所用的色谱柱、流动相、使用的检测手段以及样品的提取方法;最后针对目前存在的问题,提出了高效液相色谱用于化妆品中微量成分分析的研究方向和发展前景。 相似文献
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H. Toda Y. Mochizuki T. Kawanishi H. Kawashima 《Nutrient Cycling in Agroecosystems》2002,63(2-3):167-173
In a coastal agricultural area in the central part of Japan (Shizuoka), we found decreasing nitrate concentration with depth in a shallow groundwater, where the depth to water table varied between 0.6 and 1.2 m below ground surface. High nitrate concentrations (5–29 mg N L–1) were often observed in the upper layer (0–2 m) of the groundwater, but the concentration decreased to less than 1 mg N L–1 in the deeper layer. Ammonium was scarcely detected, and the concentration of dissolved oxygen was usually low (< 1 mgO2 L–1) in the groundwater. Nitrate in the groundwater often had very heavy nitrogen stable isotope ratios (>20{}). There was a negative relationship between nitrogen stable isotope ratio of nitrate and its concentration. When nitrate was injected into the groundwater with acetylene and bromide (a conservative tracer), nitrate concentration decreased to 20% of the initial level within 5 days, accompanied by the increase in nitrite and nitrous oxide concentration and a little change in bromide concentration. These results indicate that microbial denitrification plays a potential role in the decrease of nitrate in shallow groundwater at the study site. 相似文献