共查询到19条相似文献,搜索用时 78 毫秒
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《应用化工》2016,(3):557-560
以对氨基苯磺酸和盐酸萘乙二胺为显色剂,聚乙二醇6000为萃取剂,硫酸铵为盐析剂,建立了双水相萃取-比色法快速测定痕量亚硝酸根的分析方法,并对影响相分离的各种条件进行了优化。结果表明,当聚乙二醇6000用量3.0 m L,硫酸铵用量2.5 g,亚硝酸根的显色产物被萃取到聚乙二醇相,最大吸收波长为540 nm。亚硝酸根在2.0~80μg/L浓度范围内与吸光度呈线性关系,相关系数为0.999 24,方法的检出限为1.07μg/L,对于质量浓度为5.0μg/L和50.0μg/L的亚硝酸根进行10次反复测量,得到其相对标准偏差分别为3.09%和2.47%。该方法用于水样中亚硝酸根的测定,回收率为98.4%~102.1%。 相似文献
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综述了近年来催化动力学光度法测定痕量亚硝酸根的研究进展。具体内容包括:催化褪色动力学光度法测定痕量亚硝酸根的研究进展;催化荧光法测定痕量亚硝酸根的研究进展。评述内容包括指示反应及其条件、方法的检出限、线性范围、应用及干扰情况等,并探讨和展望了催化动力学光度法未来的研究方向和发展趋势。 相似文献
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基于磷酸介质中亚硝酸根催化溴酸钾氧化溴甲酚绿的褪色反应,建立测量痕量亚硝酸根的新方法,方法检测限为1.36×10-6g/L,线性范围为0.012~0.08μg/mL,方法已用于水中亚硝酸根的测定. 相似文献
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溴酸钾-溴甲酚绿催化光度法测定痕量亚硝酸根 总被引:2,自引:0,他引:2
基于1.5 mol/L磷酸介质中亚硝酸根在室温下对溴酸钾氧化溴甲酚绿的退色反应具有较强的催化作用,建立了测定痕量亚硝酸根的新催化光度法,研究了反应的适宜条件及动力学参数.在最大吸收波长443 nm及选择的试验条件下,线性范围为0.004~0.32 mg/L,检出限为1.2×10-9g/mL.该方法在室温下进行,操作方便,多数常见离子不干扰,灵敏度及选择性较高,直接用于水样中痕量亚硝酸根的测定,结果满意. 相似文献
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溴酸钾氧化茜素红催化光度法测定痕量亚硝酸根 总被引:6,自引:1,他引:6
本文以亚硝酸根对溴酸钾氧化茜素红而使其褪色所起的催化作用为基础,建立了一种测定亚硝酸根的新催化光度法。该方法在室温下进行,操作方便,选择性好,测定灵敏度为4.24x100 ̄(-10)g/ml的亚硝酸根,线性范围为0.2~10μg/25ml。用于环境水样中亚硝酸根的测定,相对标准偏差小于5.3%,加标回收率为90.2~107.7%。 相似文献
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提出了一种测定痕量亚硝酸根的新方法。在 p H2 .0~ 3.0酸性介质中 ,亚硝酸根与对氨基苯磺酸发生重氮化反应 ,然后在 p H6 .0~ 7.0弱酸性介质中与甲萘胺偶合生成一种紫红色偶氮染料 ,与 717型强碱性阴离子交换树脂交换 ,将该染料富集于树脂上 ,用树脂相分光光度法测定痕量亚硝酸根。其最大吸收波长位于 5 0 0 nm,方法的表观摩尔吸光系数为 2 .0× 10 5 L· (mol· cm) - 1 ,对 1.0 g树脂亚硝酸根的浓度在 0 .35~ 6 .0 μg· (2 5 m L) - 1范围内符合比尔定律。该法运用于水样及生物样品中痕量亚硝酸根的测定 ,相对标准偏差为 0 .1%~ 1.7% ,加标回收率为 90 .0 %~ 10 4.2 % ,结果令人满意 相似文献
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在磷酸介质中,亚硝酸根对溴酸钾氧化龙胆紫褪色具有较高的催化活性,由此建立了测定痕量亚硝酸根的新方法,讨论了反应的动力学条件,方法的线性范围为0.02~0.4μg.mL-1,检出限为1ng.mL-1,方法简便、快速、选择性好,适用于食品样品中亚硝酸根的测定,结果满意。 相似文献
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Rapid colorimetric determination of free fatty acids 总被引:14,自引:6,他引:8
In 1964, a method was described for the determination of free fatty acids (FFAs) in vegetable oil. This paper describes an
expansion of that work, improving the sensitivity and reproducibility of the method, as well as examination of solubilities
of the copper soaps as a function of chain length and unsaturation. Involvement of the micellar structure was reviewed. Finally,
a procedure is described that permits very rapid determination of FFA at the 2.0–14.0 μmol (0.5–4.0 mg oleic acid) level,
and the results with several oils are given. Particular attention was given to evaluation of solvent systems which would extract
the copper complexes.
Presented in part at the AOCS Meeting in San Francisco, April 1969.
Technical Paper No. 4036, Oregon Agricultural Experiment Station. 相似文献
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《Fuel》1987,66(7):996-1001
A simple and rapid method for the colorimetric determination of total nitrogen in coal has been tested on several coals digested under various conditions. The method consists of initial carbonization of the coal sample with H2SO4 followed by digestion using continuous-flow addition of a mixture of 50% H2O2 plus concentrated H2SO4. Nessler's reagent is added for colour development for the subsequent spectrophotometric determination of ammonia nitrogen. Maximum nitrogen recovery was obtained by using boiling times of 4 min or more during sample carbonization, H2O2:H2SO4 ratios of 4:1 to 9:1, and digestion reagent volumes of 20–40 cm3. Altering the heat setting on the digestion apparatus substantially changed digestion times but did not significantly affect nitrogen values obtained. Using the optimum digestion conditions, results for nitrogen in seven different coal samples were comparable with those obtained by conventional determinations using an instrumental ‘CHN’ analyser. The precision of this rapid dissolution technique was good and appeared to be better than that of the instrumental analyser for many of the coals studied. 相似文献
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<正>目前,多采用重量法测定水泥中SO3[1]。该方法的操作过程复杂,对操作人员的技术要求较高,分析周期较长,不利于质量控制。使用测硫仪测定[2],方便、快速,但是取样量少,分析误差较大,结果的重现性有待提高。对SO3含量测定最快速的方法是,直接使用酸 相似文献
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A rapid microanalytical method has been developed for the determination of very small amounts of chlorine in polymers. The gist of the method comprises quantitative dechlorination by sodium biphenyl or dehydrochlorination bytert-BuOK, aqueous extraction of the Cl? formed, followed by [Cl?] quantitation by chloride ion selective electrode (CSE). The method has been tested and is now used routinely for chlorine end group quantitation of telechelic polyisobutylene (PIB), poly(2,4,6-trimethylstyrene) (PTMSt), and poly(p-chlorostyrene) (PpClSt). 相似文献
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提出了用分光光度法测定钢材酸洗液和钝化液中亚硝酸根(或盐)的简易测定法。在硝酸介质中,NO2-与亚铁氰化钾K4[Fe(CN))6]生成黄色Fe(CN)3-6络阴离子[在低浓度溴化+六烷基吡啶(CPB)存在下],该配合物吸收峰(λmax)为430nm,摩尔吸光系数(ε)为3.5×104L/(mol·cm)。NO2-的含量在0~0.80μg/mL范围内,服从朗伯—比尔定律。一般常见阴阳离子均不干扰测定结果。 相似文献