spectroscopy in separated flames-VI The argon or nitrogen-sheathed nitrous oxide-acetylene flame in atomic-absorption spectroscopy

The separation of the premixed nitrous oxide-acetylene flame at a 50-mm slot burner by sheathing with argon or nitrogen is described. In comparison with the conventional flame, the interconal zone of the hot, slightly fuel-rich separated flames provides better conditions for the maintenance of free atoms of elements which form refractory oxides. Optimum conditions for the determination by atomic-absorption spectroscopy of the elements Al, Be, Ge, Mo, Si, Ti, V and Zr in both separated and conventional flames at the same burner have been established. Significant improvement in detection limits and sensitivities is obtained in the separated flames.     

Spectroscopy in separated flames-I. The use of the separated air-acetylene flame in thermal emission spectroscopy

The separation of a premixed air-acetylene flame is described. The interconal zone of this flame exhibits very low radiative background, and is only slightly cooler than that of a normal air-acetylene flame. The use of the separated flame in flame photometry, for which it has several pronounced advantages, has been investigated.     

Spectroscopy in separated flames-III Use of the separated nitrous oxide-acetylene flame in thermal emission spectroscopy

The separation of a premixed nitrous oxide-acetylene flame at a modified commercial burner is described. The reducing interconal zone of the fuel-rich separated flame exhibits low radiative background. The reducing atmosphere and high temperature of this flame result in an effective medium for the excitation of the atomic line spectra of the refractory elements. The use of the fuel-rich flame in the flame photometry of these elements has been investigated.     

Spectroscopy in separated flames--VII: Determination of bismuth by atomic-fluorescence spectroscopy in a separated air-acetylene flame with electronically modulated electrodeless discharge tube sources

The application of electronically modulated and unmodulated bismuth and iodine electrodeless discharge lamps as sources for the excitation of bismuth atomic fluorescence in conventional and nitrogen-separated air-acetylene flames has been investigated. Separation of the flame results in improved detection limits for bismuth even when a modulated source is employed. The effect of 500-fold weight excesses of foreign ions on the determination of bismuth at 302.46 nm with a modulated iodine source and separated flame has been studied; only calcium and zirconium are found to cause significant interference. The determination of bismuth in aluminium alloy samples is reported.     

猪肉中63种有机磷农药的气相色谱筛选与气质联用确证方法

建立了固相萃取-气相色谱筛选和气相色谱-质谱联用确证猪肉中63种有机磷农药的分析方法。样品用正己烷配合乙腈-水溶液均质提取,加入氯化钠继续均质,离心分层后取部分乙腈层经C18柱和PSA柱净化后供GC和GC-MS分析。气相色谱筛选采用火焰光度检测器（FPD）,气相色谱-质谱联用确证采用选择离子扫描方式（SIM）,外标法定量。该方法简便、快速,优化条件下测定方法的定量下限（S/N=10）为0.001～0.043 mg/kg,在加标水平为0.16 mg/kg时,回收率为70%～121%,相对标准偏差为4.1%～13.9%。     

Spectroscopy in separated flames-IV: application of the nitrogen-separated air-acetylene flame in flame-emission and atomic-fluorescence spectroscopy

The primary and secondary combination zones of an air-acetylene flame have been separated by a stream of nitrogen flowing parallel to the flame to prevent access of atmospheric oxygen to its base. The flame is very stable over a wide range of fuel-air mixture strengths, and organic solvents may be aspirated without difficulty. The low flame background enables thermal-emission and atomic-fluorescence measurements to be made with high sensitivity. Bismuth, for example, has been determined in the range 5-200 ppm by its thermal emission at 306.8 nm, with a detection limit of 2 ppm in aqueous solution, and in the range 1-10 ppm with a detection limit of 0.3 ppm in 50% ethanolic solution. Zinc and cadmium have been determined at 213.9 nm and 228.8 nm by atomic-fluorescence spectroscopy in this flame with detection limits of 2 x 10(-4) ppm and 5 x 10(-4) ppm respectively, vapour-discharge lamps being used as sources of excitation. The results obtained represent a considerable improvement over those available by the same methods in a conventional air-acetylene flame.     

AAS determination of trace elements in high-purity gold after matrix separation by solvent extraction

Summary A method is described for the determination of 20 trace elements in gold of a qualification of about 4–5 N. The matrix is separated by solvent extraction into methylethylketone/chloroform and the trace elements are determined in the aqueous phase by AAS (flame or graphite furnace). The procedure is optimized as to minimize the number of contamination sources.     

Spectroscopy in separated flames-V The argon- or nitrogen-sheathed nitrous oxide-acetylene flame in flame emission spectroscopy

The separation of the premixed nitrous oxide-acetylene flame by sheathing with argon or nitrogen is described. The interconal zone of the hot, slightly fuel-rich flame exhibits low background and noise levels and an extended reducing atmosphere, providing better conditions for the excitation of atoms of elements which form refractory oxides. The limits of detection found for nine such elements are greatly superior to those obtainable in the conventional unsheathed flame under similar conditions.     

A dual spectrophotometric/contactless conductivity detector for CE determination of incompletely separated amino acids

A new application is described of a dual photometric/contactless conductivity detector to CE determination of incompletely separated compounds. These compounds are differentiated when one of them provides signals in both the cells of the detector, whereas the other yields a signal in only one cell. The technique has been applied to determination of proline and tyrosine in a dietary supplement.     

火焰原子吸收光谱法间接测定药剂中的核黄素

本文利用高碘酸钠对相邻羟基氧化作用的专属性,在一定介质中,高碘酸钠与核黄素完全反应后,过量的高碘酸的钠与硝酸铅或者硝酸铜生成沉淀,通过测定Pb<'2+>或者Cu<'2+>,建立了间接测定核黄素含量的方法.铅体系和铜体系测定的相对标准偏差(RSD)分别为4.8%和5.2%,检出限分别为0.6μg.mL<'-1>和0.5μ...     

Determination of antimony in rocks and sulphide ores by flame and electrothermal atomic-absorption spectrometry

Atomic-absorption methods for determination of antimony at mug/g levels in rocks and sulphide ores by flame atomization (FAA) and electrothermal atomization (ETAA) have been described. The FAA method involves the separation of antimony from matrix elements by extraction as the iodide into methyl isobutyl ketone containing tri-n-octylphosphine oxide, from dilute hydrochloric acid solution, followed by direct aspiration of the extract into an air-acetylene flame. If necessary, antimony is first separated from copper and lead by co-precipitation with hydrous ferric oxide from ammoniacal medium and by precipitation of lead as lead sulphate. The ETAA method involves co-precipitation of antimony with hydrous ferric oxide followed by dissolution of the precipitate in dilute nitric acid, mixing with nickel solution as releasing agent, and ETAA measurement by use of a tungsten strip atomizer.     

The spectrochemical determination of total strontium in bone,milk and vegetation

Samples of bone ash are mixed with anhydrous copper sulphate and graphite and pelleted A d c. arc is used to excite the spectra which are then evaluated by microphotometry The effective concentration range is 50 – 350 p p. m of strontium in the ash and the coefficient of variation is 6% for single exposures at the 90 p p m levelIn the case of milk and vegetation, strontium and calcium are separated as insoluble oxalates and the strontium content of this fraction determined by a method similar to that used for bones, with a similar range and accuracy. An alternative flame photometric method is described for the determination of strontium in the calcium-strontium oxalate fraction, thc coefficient of variation of the whole analytical operation being 5% per determination     

A Dual-Channel Flame Photometric Detector with a Seperate Combustion Chamber

A new version of the dual-channel flame photometric detector is described for compounds containing phosphorus and sulphur. The sample is mixed with hydrogen before introduction into the detector. The burner is formed as a specific combustion chamber, which is separated from the emission chamber of the detector. Interference signals in the P-channel, caused by sulphur-containing compounds (crosstalk signals) are damped electrically. Thus the selectivity to hydrocarbons is increased by a factor of up to 10⁷, crosstalk signals are reduced by a factor of 10³ and flame stability is guaranteed (there are no flame-outs caused by amounts of up to 50 μl of liquid samples).     

Separation and speciation of Cr(III) and Cr(VI) with Saccharomyces cerevisiae immobilized on sepiolite and determination of both species in water by FAAS

A rapid, sensitive and accurate method for the separation, preconcentration and determination of Cr(III) and Cr(VI) in water samples is described. Chromium species can be separated by biosorption on Saccharomyces cerevisiae immobilized on sepiolite and determined by flame atomic absorption spectrometry (FAAS). The optimum conditions for separation and preconcentration (pH, bed height, flow rate and volume of sample solution) were evaluated. Recovery of the chromium was 96.3+/-0.2% at 95% confidence level. The breakthrough capacity of the adsorbent was found as 228 mumol g(-1) for Cr(III). The proposed method was applied successfully to the determination of Cr(III) and Cr(VI) in spiked and river water samples.     

微柱高效液相色谱与火焰光度检测器联用研究

报道了微柱高效液相色谱（micro-column HPLC）与火焰光度检测器（FPD）在线联用系统的研究,目的是发展一种不经复杂前处理步骤即可直接测定有机锡化合物的方法。三丁基锡氯化物（TBT）等经HPLC微柱分离后,通过毛细管连接引入特制的燃烧头,通过火焰光度检测器进行检测,对系统有关参数进行了优化和讨论。所建方法可以直接测定各种水样中的三丁基锡氯化物。     

Matrix modification--the use of protein-free solutions in the determination of metals in blood by flame atomic fluorescence and emission spectrometry

A procedure is described for matrix modification in the determination of metals in blood by flame spectrometric methods. The protein is removed by precipitation with dilute nitric acid and centrifugation and the supernatant liquid is used for direct analysis. Nitric acid is compared with other acids as the precipitant. The technique is simple, contamination-free and provides a solution which may be directly compared with aqueous calibration standards. Its application for determination of clinically important metals by flame atomic fluorescence and emission spectrometry is demonstrated.     

气相色谱法测定太白洋参中的甘露醇含量

介绍了应用气相色谱法－氢火焰离子化检测器检测太白洋参中甘露醇的方法,采用OV－225填充柱分离该法平均回收率为90．66％,检出限为0．1mg/kg。     

流动注射-原子吸收分光光度法测定彩电荧光屏壁玻璃中钾钠钙镁铁

本文应用流动注射分析-原子吸收分光光度法(FLA-AAS)测定彩电荧光屏壁玻璃中的钾、钠、钙、镁、铁的含量、对方法中可能存在的各种影响因素、干扰情况及其消除等进行了较为详细的研究.应用所建立的方法对样品测定取得了满意结果.本文对所建立的FIA-AAS法与常规AAS法进行了比较及讨论     

Ruthenium determination in synthetic purex waste solutions by AAS

A method for the determination of ruthenium in synthetic Purex waste solutions by flame AAS is described. With the usual flames and a lanthanum buffer, only cerium interference in the air-acetylene flame need be considered under the conditions applied. Ruthenium nitrosyl nitrate, ruthenium(IV) hydroxychloride and alkaline ruthenate samples gave identical results, showing that the extraordinarily stable Ru-NO bond does not hinder atomization. The preparation and standardization of the ruthenium nitrosyl solutions, and the alkaline fusion, are briefly described.     

Applications of a slotted tube atom trap and flame atomic absorption spectrophotometry: Determination of antimony in copper based alloys

A sensitive system is described for the determination of antimony in copper-based alloys by flame atomic absorption spectrophotometry. The use of a slotted tube quartz atom trap improves precision and reduces the characteristic concentration by factors of 3 and 1.6 compared with the use of conventional flame AAS. Interferences are minimised by coating the internal surfaces of the STAT with copper.