卡尔曼滤波分光光度法同时测定水中微量砷和磷

研究了砷钼酸和磷钼酸与乙基罗丹明Ｂ的缔合物的吸收光谱，并以卡尔曼滤波算法对这两个严重重叠的光谱进行数据解析，达到了不需分离和掩蔽而同时测定砷和磷的目的，本法准确，精密，应用于水样分析，获得满意结果。     

光度法连续测定钼中微量磷砷

本文研究了钼(包括三氧化钼、钼酸铵)中微量磷、砷光度法的连续测定。在0.6—1.2mol/L及1.0—1.6 mol/L硝酸中,磷、砷分别与钼酸氨生成磷、砷钼酸,再分别用磷、砷萃取剂萃取,还原为磷、砷钼蓝并反革取于水相进行光度测定。方法操作简便,灵敏度高,磷ε_(780)=1.54×10~4,砷ε_(780)=2.24×10~4。测定范围1—100ppm,相对偏差为7.9—26%。     

碱性染料杂多酸多元络合物显色反应的研究Ⅷ.乙基罗丹明B分光光度法同时测定痕量磷和砷

本文利用乙基罗丹明B(ERB)和磷钼酸(PMo)或砷钼酸(AsMo)缔合物吸光度具有加和的特性,建立了在同一显色条件下,用ERB同时测定痕量磷和砷的水相光度法,方法具有灵敏、简便和快速的优点,已成功地用于钢和试剂中痕量磷和砷的同时测定,试剂中磷和砷的测定下限分别为2×10~(-6)％(1g)和5×10~(-6)％(1g)。     

分光光度法测含铌磷酸盐激光玻璃中硅的含量

测低含量的二氧化硅,分光光度法比较适用,但在类似条件下,磷、砷也和钼酸铵形成杂多酸,干扰测定,虽然可利用两种杂多酸形成速度不同,而同时测定硅和磷,或利用两种杂多酸稳定常数不同加入络合剂使磷分解,硅钼酸仍能稳定存在而进行硅的测定,但磷含量不能大于硅含量的150倍,否则会形成磷钼酸沉淀,使测定无法进行。本文提出加入适量的乙醇,可阻止磷钼酸沉淀.当铌、磷共存时加入常量的双倍掩蔽剂能消除铌、磷共存时产生的干扰.     

磷、砷、硅共存时用结晶紫测定磷

本文研究了聚乙烯醇(PVA-124)存在下,磷、砷、硅共存时以结晶紫-磷钼酸直接在水相测定磷的掩蔽体系,并探讨了各个元素分别测定的可能性。 1.主要试剂和仪器:磷、砷和硅的标准溶液按常法配制。所用仪器主要为72型分光光度计。 2.聚乙烯醇存在下用结晶紫测定磷的条件:量取磷标准溶液适量于25ml比色管中,加入H_2SO_4(5N)4.0ml,钼酸铵溶液(0.05M)2.0ml,聚乙烯醇溶液(2.5％)2.5ml,结晶     

还原磷钼杂多酸-分光光度法测定钢铁中磷——用赤霉素作新还原剂

用钼蓝法测定磷已有报导,常用的还原剂有氯化亚锡、硫酸肼和抗坏血酸等。用上述还原剂时,所生成的磷钼蓝的颜色有的很快减弱,有的显色速度很慢,且还原剂本身易被空气氧化。我们曾提出以赤霉素为还原剂,对砷钼酸的还原反应进行了系统的研究,并用于血液和茶叶中微量砷的光度测定,分析结果甚佳。本文报导用赤霉素作还原剂,以钼蓝光度     

磷砷共存时磷的光度法测定——酒石酸掩蔽砷

在一些材料中磷、砷是共存的,由于砷钼杂多酸形成条件与磷钼杂多酸相似,因此砷对磷的测定有干扰。目前应用的光度法中为消除砷对测磷的干扰,普遍采用氢溴酸除砷或萃取分离。但萃取分离,只能解决低含量磷和砷的定量分离,高砷试样中仍需氢溴酸除砷后测定磷。本文利用酒石酸抑制砷钼杂多酸的形     

以热力学和动力学性质差异连续高敏测定磷和砷及其比较研究

提出以非离子表面活性剂使磷钼酸、砷钼酸－孔雀绿缔合物在水相增敏、增溶、增稳并根据磷（Ⅴ）、砷（Ⅴ）的氧化性差异及形成上述缔合物速率差异，分别建立了以热力学和动力学性质差异在水相不经分离、连续、简便、高敏测两组分的光度法，并对此两法进行了比较研究。摩尔吸光系数ε６５０分别为１．１１×１０５（磷）和１．２２×１０５（砷）Ｌ·ｍｏｌ－１·ｃｍ－１；服从比尔定律的浓度范围相应为０～０．２４和０～０．４８μｇ／ｍＬ。已成功地用于测定四种钢样（相对误差：热力学法皆不大于±５％，动力学法通常皆不大于±１０％）和两种茶样（回收率：热力学法为９８～１０２％，动力学法为９３～１１１％）。     

高纯碳酸锂中痕量磷,砷的孔雀绿—磷（砷）酸钼浮膜分光光度法测定

本文研究了孔雀绿与磷（砷）酸钼离子对膜的形成条件，并依此与基体分离，进行痕量磷，砷的浮膜－分光光度法测定。选用硫酸为介质，考察了２５种共存离子对测定的影响。拟定了高纯碳酸锂中痕量磷，砷的分析方法，操作简便，结果令人满意。     

五氧化二钒中微量砷和磷的直接同时测定

提出了以数学校正扣除基体四价钒色泽对砷(磷)铋钼蓝色泽干扰的方法和校正磷对砷测定干扰的方法.应用于五氧化二钒中微量砷和磷的测定,结果准确、可靠.     

A method for bulk hydrogen analysis based on transmission and back scattering of fast neutrons

A method was proposed for bulk hydrogen analysis. It is based on simultaneous detection of transmitted fast neutrons and back scattered thermal neutrons from the investigated samples by ³He detectors. The fast neutron beams were obtained from ²⁵²Cf and Pu–Be neutron sources. The experimental set-up as well as samples preparation were described. Incident thermal neutrons beams obtained from either ²⁵²Cf or Pu–Be sources, were used to investigate the samples by neutron backscattering. The results obtained from transmission and backscattering of fast neutrons were compared and discussed. The advantage and capabilities of the proposed method were presented. The results obtained using fast neutron beams are more sensitive than those obtained using thermal neutron beams. Validation procedures were proposed to credit the results.     

Flow injection analysis of high chloride levels in electroplating baths using on-line dialysis and potentiometric detection

A method for the flow injection analysis (FIA) of high concentrations of chloride in electroplating baths using potentiometric detection is proposed. The system includes a unit of dialysis to promote dilution of samples and a tubular electrode with an homogeneous crystalline membrane as detector. The system was optimized in order to analyse samples within a broad range of concentrations and at high levels of chloride, thereby making pretreatment of the samples unnecessary. It results in a simple manifold applicable over the 4.0×10^–2 and 3.0 mol L^–1 range with a throughput of about 30 samples/h. Seven different plating bath samples were analysed by the proposed method and the quality of the results compared with those obtained by the conventional procedure. Satisfactory agreement was observed.     

Development of gas chromatography-mass spectrometry following headspace single-drop microextraction and simultaneous derivatization for fast determination of short-chain aliphatic amines in water samples

In this work, for the first time, gas chromatography-mass spectrometry (GC-MS) following headspace single-drop microextraction (HS-SDME) and simultaneous derivatization was developed for fast determination of short-chain aliphatic amines (SCAAs) in water samples. In the proposed method, SCAAs in water samples were headspace extracted and concentrated by suspending a microdrop of solvent, and SCAAs extracted in the microdrop of solvent were simultaneously and rapidly reacted with pentafluorobenzaldehyde (PFBAY). The formed SCAA derivatives were analyzed by GC-MS. The HS-SDME parameters of solvent selection, solvent volume, sample temperature, extraction time and stirring rate were studied, and the method linearity, precision and detection limits, were also studied. The results show that the proposed method provided good linearity (R(2)>0.99, 5.0-500 ng/ml), low detection limit (0.6-1.1 ng/ml), and good precision (RSD value less than 10%). The proposed method was further tested by its application to quantitative analysis of SCAAs in four wastewater samples. The experiment results have demonstrated that GC-MS following HS-SDME and simultaneous derivatization is a simple, rapid and low-cost method for the determination of SCAAs in water samples.     

Determination of ammonium in river water and sewage samples by capillary zone electrophoresis with direct UV detection

We developed capillary zone electrophoresis (CZE) with direct UV detection for determination of ammonium in environmental water samples. Ammonium in the samples was partly converted into ammonia in the alkaline background electrolyte (BGE) during migration and was detected by molecular absorption of ammonia at 190 nm in approximately 7 min. The limit of detection (LOD) for ammonium was 0.24 mg/l (as nitrogen) at a signal-to-noise ratio of three. The respective values of the relative standard deviation (RSD) of peak area, peak height, and migration time for ammonium were 2.1, 1.8, and 0.46%. Major alkali and alkaline earth metal ions coexisting in the samples did not interfere with ammonium determination by the proposed method. The proposed method determined ammonium in surface water and sewage samples. The results were compared to those obtained using ion chromatography (IC).     

乘子法在多组分光度分析中的应用

报道了将乘子法用于样品中多组分的分光光度法同时测定;介绍了乘子法的原理和计算步骤。对复方新诺明模拟样中磺胺甲恶唑、甲氧苄氨嘧啶测定的平均回收率分别为９９．７９％,１００．６７％,ＲＳＤ分别为０．４５％．０．９５％（ｎ＝９）,测定了５个批号复方新诺明片剂和针剂的含量,结果满意。     

Simultaneous determination of nitrite and nitrate in potato and water samples using negative electrospray ionization ion mobility spectrometry

Nowadays, nitrite and nitrate ions are analyzed in biological samples using laborious and expensive methods; such as HPLC, CE, MS-MS. In this work, the simultaneous analysis of nitrite and nitrate ions was conducted by electrospray ionization-ion mobility spectrometry (ESI-IMS), without using any complicated or laborious derivitization step. Ion mobility spectrometry with low cost, inexpensive maintenance and very fast analysis makes an attractive technique for the simultaneous determination of these ions in foodstuff and drinking water samples. The analyte interference was systematically investigated for binary mixture analysis. The obtained results provided detection limits of 3.8 and 4.7 μg/L for nitrite and nitrate, respectively. A linear dynamic range of about 2 orders of magnitude, and relative standard deviations below 5% were obtained by the proposed method for the analysis of both ions. Also, the proposed method was used to analyze various real samples of potato and drinking water samples, and the obtained results confirmed the capability of negative ESI-IMS for the simultaneous detection of nitrite and nitrate.     

顶空固相微萃取-气相法测定酒中的甲醇和杂醇油

 采用环氧树脂作为固相涂层制作固相微萃取 (SPME)装置 ,建立了顶空固相微萃取 气相法 (HS SPME GC)测定酒精饮料中甲醇和杂醇油的方法 ,并对萃取条件和条件进行了优化。方法的检出限为 0 0 2mg/L～0 0 4mg/L ,相对标准偏差为 1 4 %～ 4 1% ;与顶空气相法相比 ,灵敏度可提高 2 0倍～ 30 0倍。将该法用于啤酒、葡萄酒和保健酒中的甲醇和杂醇油的测定 ,加标回收率为 80 8%～ 110 3% ;与顶空气相法 (国家标准方法 )进行了比较 ,相对误差不大于 7 3%。该法简便、快速、灵敏、精密度好 ,拓宽了SPME的应用范围。     

Spectrophotometric Simultaneous Determination of Amaranth,Ponceau 4R,Allura Red and Red 2G by Partial Least Squares and Principal Component Regression Multivariate Calibration

ABSTRACT

The multivariate calibration methods, partial least square regression type 1 (PLS 1) and principal component regression (PCR), were proposed for the simultaneous spectrophotometry determination of Amaranth (E-123), Ponceau 4R (E-124), Allura red (E-129) and Red 2G (E-128) in their mixtures. The parameters of the chemometric procedures were optimized and the proposed method was validated with synthetic samples and applied to analyze these dyes in spiked samples of beverages with satisfactory results.     

Solid‐phase extraction combined with dispersive liquid–liquid microextraction for the determination of pyrethroid pesticides in wheat and maize samples

A rapid, selective and sensitive sample preparation method based on solid‐phase extraction combined with the dispersive liquid–liquid microextration was developed for the determination of pyrethroid pesticides in wheat and maize samples. Initially, the samples were extracted with acetonitrile and water solution followed phase separation with the salt addition. The following sample preparation involves a solid‐phase extraction and dispersive liquid–liquid microextraction step, which effectively provide cleanup and enrichment effects. The main experimental factors affecting the performance both of solid‐phase extraction and dispersive liquid–liquid microextration were investigated. The validation results indicated the suitability of the proposed method for routine analyze of pyrethroid pesticides in wheat and maize samples. The fortified recoveries at three levels ranged between 76.4 and 109.8% with relative standard deviations of less than 10.7%. The limit of quantification of the proposed method was below 0.0125 mg/kg for the pyrethoroid pesticides. The proposed method was successfully used for the rapid determination of pyrethroid residues in real wheat and maize samples from crop field in Beijing, China.     

Extraction and determination of hexavalent chromium in soil samples

A procedure for the extraction of Cr(VI) from solid soil-like samples was presented in which the complexing properties of diethylenetriaminepentaacetic acid (DTPA) were exploited to extract insoluble compounds of Cr(VI). A concentration of DTPA in an ammonium sulphate/ammonium hydroxide buffer equal to 0.02 mol l⁻¹ was chosen. The conditions of extraction of insoluble Cr(VI) from solid samples were optimised using soil certified reference material spiked with known concentration of insoluble Cr(VI) added as PbCrO₄. The extracts were analysed by adsorptive stripping voltammetry. Validation of the proposed procedure of extraction was carried out by analysis of certified reference material (CRM) 545 and comparison of the results obtained using the proposed and other methods of extraction in the course of analysis of natural soil samples.