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1.
The flow-injection determination of Paraquat (1,1′-dimethyl-4,4′-bipyridinium) is based on its reduction with sodium dithionite in alkaline medium and detection at 605 nm. Linear calibration plots are obtained for 0.1–1.0, 1.0–10 and 5.0–30.0 mg l?1 Paraquat, the lower limit being 40 times less than that of the usual spectrophotometric method. The method is applied to determine Paraquat in spiked potable water and potatoes after preconcentration by column ion-exchange. The determination of Paraquat in different herbicide samples yielded results in good agreement with those obtained by polarographic and manual spectrophotometric methods. 相似文献
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Summary A method is described for the flow-injection spectrophotometric determination of beryllium in Cu-Be-alloys using xylenol orange as reagent. Cu, Co and Fe are masked by means of thiosulphate and EDTA. Absorbance is measured at the maximum of 493 nm. With a flow rate of 4 ml/min 60 samples can be analyzed per hour with a relative standard deviation of about 1%.
Bestimmung von Beryllium in Cu-Be-Legierungen durch Flow-Injection-Spektralphotometrie
Zusammenfassung Als Reagens zur spektralphotometrischen Bestimmung von Berryllium in Cu-Be-Legierungen dient Xylenolorange. Cu, Co und Fe werden mit Hilfe von Thiosulfat und EDTA maskiert. Die Messung erfolgt im Absorptionsmaximum des Komplexes von 493 nm. Bei einer Durchflußgeschwindigkeit von 4 ml/min können 60 Proben je Stunde mit einer relativen Standardabweichung von etwa 1% analysiert werden.相似文献
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Meng JX Wang XB Ruan GL Li GQ Deng ZX 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(5):823-827
A kinetic method for determination of chlorine in air was described in the present work. The method based on fading of methyl orange (MO) containing solution in air absorption process. A determination limit of 2.64 microg L(-1) was found. With the present method, chlorine concentration could be determined in several minutes with convenient manipulation. As concentration variation of methyl orange in the absorption solution did not affect the experimental results, fabrication and preservation of the stock absorption is also convenient. The present method is promising in monitoring chlorine concentration in atmosphere. 相似文献
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An automated procedure is proposed for the spectrophotometric determination of sucrose in sugar-cane juice and nonlasses. The previously diluted and filtered sample is introduced into a flow-injection analyzer designed with two merging streams, producing two samples zones. One zone is transported directly towards the merging-stream confluence; the other zone reaches this site after flowing through a heated coil in which partial and reproducible sucrose inversion is attained under controlled conditions of acidity and temperature. At the confluence point, a buffered periodate stream is added to oxidize the sugar. The consumption of periodate, which mainly reflects the fructose content, is measured spectrophotometrically as a transient lowering of the iodine concentration, produced by reaction of periodate with iodide. The two processed zones proceed sequentially to the flow cell and two peaks are recorded. The sucrose content in the sample is proportional to the difference in peak heights. System dimensioning and the effects of temperature, pH, reagent concentrations, flow rates and the presence of other reducing sugars in the sample are discussed. With the proposed system, about 30 sugar-cane juice samples can be analyzed per hour, and sample clarification is not required. Precise results (r.s.d. <1%), in agreement with those obtained by h.p.l.c., are achieved for sucrose contents of 11–14% (w/v) in cane juice. Modifications of the system for analysis of molasses (16–52% w/w sucrose) are described. 相似文献
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In this work, a solid phase spectrophotometric method in association with flow injection analysis for formaldehyde determination has been developed with direct measurement of light-absorption in C18 material. The 3,5-diacetyl-1,4-dihydrolutidine produced from the reaction between formaldehyde and fluoral P was quantitatively retained on C18 support and the spectrophotometric detection was performed simultaneously at 412 nm. The retained complex was quickly eluted from C18 material with the eluent stream consisting of a 50% (v/v) ethanol solution. The results showed that the proposed method is simple, rapid and the analytical response is linear in the concentration range of 0.050-1.5 mg L−1. The limit of detection was estimated as 30 μg L−1 and the R.S.D. 2.2% using a sample volume of 625 μL. The system presented an analytical throughput of 20 determinations per hour. The method was successfully applied in the determination of formaldehyde in ethanol fuel. 相似文献
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Determination of uranium in tap water by ICP-MS 总被引:23,自引:0,他引:23
A fast and accurate procedure has been developed for the determination of uranium at microg L(-1) level in tap and mineral water. The method is based on the direct introduction of samples, without any chemical pre-treatment, into an inductively coupled plasma mass spectrometer (ICP-MS). Uranium was determined at the mass number 238 using Rh as internal standard. The method provides a limit of detection of 2 ng L(-1) and a good repeatability with relative standard deviation values (RSD) about 3% for five independent analyses of samples containing 73 microg L(-1) of uranium. Recovery percentage values found for the determination of uranium in spiked natural samples varied between 91% and 106%. Results obtained are comparable with those found by radiochemical methods for natural samples and of the same order for the certified content of a reference material, thus indicating the accuracy of the ICP-MS procedure without the need of using isotope dilution. A series of mineral and tap waters from different parts of Spain and Morocco were analysed. 相似文献
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Susumu Nakashima Masakazu Yagi Michio Zenki Mitsuo Doi Kyoji Tôei 《Fresenius' Journal of Analytical Chemistry》1984,317(1):29-31
Summary Sulphate was determined in natural water samples by flow-injection analysis using dimethylsulphonazo-III as reagent. The interference by Ca was eliminated by a cation-exchanger column inserted directly after the sample injection valve. In order to ensure high sensitivity and reproducibility it was necessary to saturate the carrier solution with barium sulphate and to fill the reaction coil with ethanol-water (11) when not in use. Standard deviations were 0.94–1.2% for 6–10mg/l sulphate. The limit of detection was about 0.2mg/l. The calibration graph was linear up to 14mg/l Mg2+, NH
4
+
, Na+, K+, Cl–, NO
3
–
, PO
4
3–
, HCO
3
–
and SiO
3
2–
did not interfere in the normally occurring concentrations.
Sulfatbestimmung in natürlichem Wasser durch Flow-Injection-Analyse
Zusammenfassung Als Reagens dient Dimethylsulfonazo-III. Die Störung durch Calcium bei dieser Bestimmung wird durch eine Kationenaustauschersäule eliminiert, die direkt nach dem Probeinjektions-Ventil angeordnet ist. Zur Erhöhung der Empfindlichkeit und Reproduzierbarkeit ist es notwendig, die Trägerlösung mit Bariumsulfat zu sättigen sowie bei Nichtbenutzung des Systems den Reaktionsteil mit Ethanol-Wasser (11) zu füllen. Mit dem so modifizierten Verfahren ergaben sich Standardabweichungen von 0,94–1,2% für 6–10 mg/l Sulfat, die Nachweisgrenze liegt bei 0,2 mg/l. Die Eichkurve ist bis 14 mg/l linear. Mg2+, NH 4 + , Na+, K+, Cl–, NO 3 – , PO 4 3– , HCO 3 – und SiO 3 2– stören in den normalerweise vorkommenden Konzentrationen nicht.相似文献
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Biological tissues are digested with nitric and perchloric acids in a heated aluminium block. Flow-injection spectrophotometry is then used to measure phosphate via the phosphovanadomolybdate complex at 413 nm. The detection limit is 0.3 μg ml?1 phosphorus; relative standard deviations are 0.7% and 0.4% at 1 μg ml?1 and 25 μg ml?1 phosphorus, respectively. Interferences are discussed. The decomposition procedure is evaluated for model compounds and standard reference materials. 相似文献
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A turbidimetric flow-injection system was developed for the determination of sulfate in natural and residual water samples, with no previous treatment, using spectrophotometric detection. The precipitating agent, 7.0% (w/v) barium chloride solution prepared in 0.10% (w/v) polyvinyl alcohol, was added by using the merging-zones approach. A 100 mg/L sulfate solution in 0.07M nitric acid was mixed with the sample before it entered the injection loop to improve the detection limit, provide in-line pH adjustment, and prevent the interference of some anionic species. The relative standard deviations of the results were between 1.4 and 3.0% and were in agreement with results obtained by the reference method. Samples within a linear concentration range of 10-120 mg SO4(2-)/L can be analyzed at a rate of 40/h. The detection limit is 5 mg SO4(2-)/L. 相似文献
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The determination of chlorine with o-tolidine in greywater has been studied, and a batch method and a sequential injection method have been proposed. It was found that the reaction of o-tolidine with chlorine was slower in a greywater matrix. Grey water samples must be filtered before analysis, or alternatively, a blank of sample must be measured. The samples are very unstable, and after 2 h of storage in dark conditions at 4 degrees C the chlorine concentration can diminish. The standard addition method, in some samples gave unsatisfactory results as a consequence of matrix effects. It was concluded that samples with a total organic carbon (TOC) higher than 60 mgCl(-1) can not be accurately analysed using these methods. However, samples with a TOC lower than 60 mgCl(-1) gave 100+/-3% recoveries. The linear range of the methods was 0-3.0 and 0-5.0 mgCl(2)l(-1), and the limit of quantification 0.2 and 0.5 mgCl(2)l(-1), for the batch method and the sequential injection method, respectively. This is the first paper devoted to grey water from the analytical chemistry point of view. 相似文献
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Residual chlorine is measured in water by using a potentiometric system composed of an iodide-selective electrode and a platinum electrode sensing the iodine-iodide ratio. When the sample is added to acidified iodide solution, the cell response is in a logarithmic relation to the iodine concentration which in turn depends on the concentration of residual chlorine. In the flow injection system evolved, 0.1–5.0 mg l-1 residual chlorine can be determined at a rate of 40–60 samples per hour. The results of potentiometric determinations of residual chlorine in tap water compared to spectrophotometric results suggest that the presence of various organic substances is responsible for discrepancies between these measurements. 相似文献
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A flow-injection UV spectrophotometric method was developed for the determination of ambroxol hydrochloride in tablets. The
quantitative determination of ambroxol was performed at 245 nm using distilled water as the carrier solvent. In this study,
the flow rate, loop volume, and the number of injections per hour were 15 mL/min, 193 μL, and 100, respectively. The analytical
signal of ambroxol was linear in the concentration range of 40–200 μg/mL. The detection limit and limit of quantification
were found as 11.55 and 38.49 μg/mL, respectively. The results for the determination of ambroxol in tablets, 29.99 ± 0.23
mg (mean ± SD), were in good agreement with the labeled quantities (30 mg/tablet). A relatively high recovery value (100.4%)
shows the accuracy of the proposed method. Furthermore, the results obtained were in accordance with those obtained by the
HPLC method, which were used as a comparison method for the determination of ambroxol HCl, as far as the Student’s t-test
and Fisher test results were concerned. It was concluded that the proposed flow-injection UV spectrophotometric method was
fast, accurate, precise, and suitable for automation in the determination of ambroxol.
The text was submitted by the authors in English. 相似文献
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流动注射分光光度法测定亚硝酸根氮 总被引:1,自引:0,他引:1
使用北京吉天仪器有限公司水质分析仪样机建立了测定水中痕量亚硝酸根氮的流动注射光度方法,以先进的光纤光谱仪CCD作为检测器,亚硝酸盐与对氨基苯磺酰胺重氮化,再与盐酸N-(1-萘基)乙二胺偶合,形成玫瑰红色的偶氮染料,用分光光度法测定,其最大吸收峰在540nm处;最佳的显色管路长度1.5m;最佳的对氨基苯磺酰胺质量浓度为1.0g/L;最佳的N-(1-萘基)乙二胺质量浓度为60g/L,亚硝酸根氮的线性范围为0.002~1.0mg/L,检出限0.37μg/L,RSD0.2%,实际样品的加标回收率均在96.5%~101.2%之间,测定频率60样/h。 相似文献
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Flow-injection amperometry with two polarized platinum electrodes is used for the determination of residual chlorine based on the oxidation of iodide. Interferences of iron(III), copper(II), nitrite and atmospheric oxygen are eliminated in the proposed procedure. The detection limit for residual chlorine is 2 μg l?1 at a sampling rate of 120 h?1; linear calibration graphs are obtained up to 0.8 mg 1?1. A method for the simultaneous flow-injection determination of residual chlorine and copper(II) is also proposed. 相似文献
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刚果红分光光度法测定水中亚硝酸根 总被引:3,自引:0,他引:3
测定亚硝酸根离子的标准方法是Griss法。但是所用α-萘胺或盐酸萘乙二胺均为强致癌试剂,同时它们的性质不稳定,见光易变质变色。使用不方便。近几年有许多分析工作者致力于选用新型无毒试剂替代致癌试剂测定环境样品中亚硝酸根。刚果红是一稳定无毒的酸碱指示剂。 相似文献