STUDY ON THE DETERMINATION OF TRACE BISMUTH(Ⅲ) BY THIN-LAYER RESIN PHASE SPECTROPHOTOMETRY

In this paper, a new thin-layer ion-exchange resin phase analytical method is introduced. It is based on that, the bismuthous cation can associate with iodic anions, so as to formed an anioncomplex [BiI-4] in a strong acidic environments. This anion complex can also exchanges with a weaker anions on the surface active site of anion exchange resin, so that a [R+] [BiI-4] solid phase binary associational system is produced. Owing to the solid system is a great many dispersive particulates, it can be pressed to a thin-layer by press tools of the so called "thin-layer resin phase"or "resin phase ", and using this solid association system spectrophotometry for the determination of trace metals. So it can increase the analytical sensitivity. This association system exhibits maximum absorbance at 460nm, and obeys Beer's law over the concentration range 0. 01ug/ml～1.20ug/ml of bismuthous(Ⅲ). It has a molar absorptivity of 7.1 ×105 [L/mol cm]. It indicated the resin phase spectrophotometry is a sensitive analytical method for trace bismuthous. It is 18 times higher than routine aqueous spectrophotometry. The relative standard deviations is 1.82% (n=6) for the measurements of 0. 5ug/ml Bi(Ⅲ). The detection limit of Bismuthous(Ⅲ) is 1.4 ×10-8mol/L. The method has applied to the analysis Bi(Ⅲ) in environmental water samples.     

STUDY ON DETERMINATION OF TRACE Fe BY Fe(Ⅱ)-VA THIN LAYER RESIN PHASE SPECTROPHOTOMETRY

1. INTRODUCTION Since the solid spectrophotometry was first mentioned by Jiyong in 1976, the solid spectrophotometry has been widely concerned by analytical chemists because it incorporate concentration, separation and determination, has a high sensitivity (which is 10~100 times higher than that of liquid phase spectrophotometry) and has a good selectivity. In solid spectrophotometry, the resin phase spectrophotometry is used widely [1~10]. But traditional spectrophotometry need a special…     

STUDY ON THE DETERMINATION OF TRACE Fe(Ⅲ) BY THIN LAYER RESIN PHASE SPECTROPHOTOMETRY

A method to determine Fe(Ⅲ) by thin layer resin phase spectrophotometry has been developed in this paper. The colored complex formed by Fe(Ⅲ) and 1,2-benzendiol is concentrated on the 717# resin, then Fe(Ⅲ) can be determined directly by making thin layer. The method is sensitive with a apparent molar absorption of 4.8×104L/mol. cm, which is 16 times higher than that of liquid phase spectrophotometry, most coexisting ions do not influence the determination. The detection limit for Fe(Ⅲ) is 1.47μg/L with the precision of 3.3% [n=6, 7μg/50mL Fe(Ⅲ)]. The calibration curve is linear in the range of 0～25μg/50mL. The preposed method was applied to the determination of Fe(Ⅲ) in water sample with satisfactory results.     

ADSORPTION OF SAMARIUM（III） ON DIGLYCOLAMIDIC ACID RESIN

The sorption behavior and mechanism of a novel chelate resin, diglycolamidic acid resin (DAAR), for Sm(lll) were investigated. The optimal sorption condition of DAAR for Sm(lll) is pH=6.0 in HAc-NaAc medium. The statically saturated sorption capacity is 190mg/g resin at 298K. The Sm(lll) adsorbed on DAAR can be eluted reaching 100% by 0.5-2.0mol/L HCI used as eluant. The resin can be regenerated and reused without apparent decrease of sorption capacity. The apparent sorption rate constant is k298= 1.96×10^-5s^-1. The apparent activation energy is 26kJ/mol. The sorption behavior of DAAR for Sm(lll) obeys the Freundlich isotherm. The thermodynamic sorption parameters, enthalpy change ΔH of DAAR for Sm(lll) is 16.9Kl/mol. The molar coordination ratio of the functional group of DAAR to Sin (111) is 3. The sorption mechanism of DAAR for Sm(lll) was examined by using chemical method and IR spectrometry. The coordination bond was formed between oxygen atoms in the functional group of DAAR and Sin(Ill).     

STUDY ON DETERMINATION OF TRACE Cu(Ⅱ) BY DDCT CHELATING RESIN PRECONCENTRATION AND THIN LAYER RESIN PHASE SPECTROPHOTOMETRY

1. INTRODUCTION Resin phase spectrophotometry belongs to solid spectrophotometry. It is a new kind of luminosity analysis technology, which comes from the combination of solid extraction technology and luminosity analysis technology. This method is especially suitable for analyzing low component environment water sample, high purity substance and complicated sample component because it incorporates sensitivity (associated by ion exchange), concentration, separation and determination. So m…     

STUDY ON THE DETERMINATION OF TRACE Fe（III） BY THIN LAYER RESIN PHASE SPECTROPHOTOMETRY

A method to determine Fe（Ⅲ） by thin layer resin phase spectrophotometry has been developed in this paper. The colored complex formed by Fe（Ⅲ） and 1,2-benzendiol is concentrated on the 717^# resin, then Fe（Ⅲ） can be determined directly by making thin layer. The method is sensitive with a apparent molar absorption of 4.8×10^4L/mol.cm, which is 16 times higher than that of liquid phase spectrophotornetry, most coexisting ions do not influence the determination. The detection limit for Fe（Ⅲ） is 1.47μg/L with the precision of 3.3% [n=6, 7μg/50mL Fe（Ⅲ）]. The calibration curve is linear in the range of 0-25μg/50mL. The preposed method was applied to the determination of Fe（Ⅲ） in water sample with satisfactory results.     

气相色谱法测定线虫中的脂肪酸含量

ematode is a small organism and the traditional purification method needs a lot of nematodes , but it is difficult for us to foster many nematodes.The fatty acids in nematode were esterified directly in our analytical method,so that,the error is reduced the and sensitivity is improved. The results showed that thisimproved analysis method could be used for rapid and satisfactory determination of the fatty acid change during storagr of this group of nematodes.     

A New Kinetic Method of Processing TA Data

A new method of investigating the kinetic parameters and mechanism functions of a solid phase reaction is presented. This method is to analyze the data based on the use of these data at the same temperature and the same degree of conversion on a series of TA curves with different heating rates, so that the kinetic triplet--the activation energy E, the pre-exponential factor A and the analytical form of the function of conversionf(α) can be obtained. The main advantage of this method is that the values of E and f(α) are obtained respectively, and the determination of f(α) is not under the influence of the value of E and the calculation of the value of E is not influenced by thef(α) either.     

Flow-Injection Electrochemiluminescence Detecting Rifampicin Based on Its Sensitizing Effect

Introduction Rifampicin, a semi synthetic compound, is used primarily in the treatment of tuberculosis, and it is also an excellent amistaphyloco antibiotic when used in combination with other antibiotics, so it is very useful clinically.1 Therefore, the determination of rifampicin has attracted much attention. From now on, techniques for the determination of rifampicin have been primarily based on spectrophotometry,2 double-wavelength thin-layer scan,3 chemiluminescence,4 high performance liq…     

Preparation of true solutions of monomeric amyloidogenic protein/peptide: A critical prerequisite for aggregation kinetic study

Our dynamic laser light scattering(LLS) study shows that the current widely used protocols of dissolving amyloidogenic protein/peptide do not really result in a true solution;namely,there always exist a trace amount of interchain aggregates,which greatly affect the association kinetics,partially explaining why different kinetics were reported even for a solution with identical protein and solvent.Recently,using a combination of the conventional dissolution procedure and our newly developed ultra-filtration method,we have developed a novel protocol to prepare a true solution of amyloidogenic protein/peptide without any interchain aggregates.The resultant solutions remain in their monomeric state for at least one week,which is vitally important for further study of the very initial stage of the interchain association under the physiological conditions because more and more evidence suggests that it is those small oligomers rather than large fabric aggregates that are cytotoxic.In addition,this study shows that combining static and dynamic LLS can lead to more physical and microscopic information about the protein association instead of only the size distribution.     

Post column derivatization with a lead dioxide solid phase reactor as part of a continuous chromatographic detection system: Speciation measurements of chromium

Summary A post chromatographic chemical reaction detector is described for the determination of Cr (III) and Cr (VI) in the range of 100ng/ml to 10μg/ml. All chromium species which exist in a lower oxidation state than the sixvalent form are oxidized to chromate in a lead dioxide solid phase reactor. The detection is performed by complexation of the chromate with 1,5-diphenylcarbazide, which forms a red-violet complex detectable at 540 nm. The conditions which are necessary for a fast oxidation inside the solid phase reactor are discussed. The system which can also be run in the flow injection mode is applied to measurements of synthetic waste waters and to samples from a steel work. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984     

STUDY ON ELECTROOXIDATION OF TRACE CO(Ⅰ) REACTION KINETICS ON Pt/C CATALYST

We have determined experimentally the reaction kinetics of the electrocatalytic oxidation of the trace carbon monoxide on Pt/C catalyst in aqueous sulphuric acid.At the constant potential 0.947V vs.NHE,the overall rate equation may be expressed bywhere y is a parameter relating to the concentration of H3O .Assuming that the rate of the electrocatalytic oxidation of carbon monoxide is controlled by the edectrochemical reaction of the adsorbed CO and adsorbed OH and that t the surface of catalyst is homogeneous,we can obtain a theoretical rate equation which is formally the same as the empirical rate equation.Recently,instruments for monitoring trace toxic gases in atomosphere based on electrochemical principles have been reported The determinable gases may involve CO,SO2H2S,nitrogen oxides,various gaseous paraffins,and so on.This new method raises wide interests for its many cdvantages,for instance,the price is cheap: the operation is simple and it can be used directly to monitor atmospheric toxic gases     

Determination of trace calcium by solid substrate-room temperature phosphorimetry

A new method for the determination of trace calcium by solid substrate-room temperature phosphorimetry is established. It is based on the fact that chromeazurols azurol S-phenanthroline-NaCMC (CAS-phen-NaCMC) system can emit strong and stable room temperature phosphorescence (RTF) on the solid substrate in the filter paper. Ca2 and phenanthroline can form complex ion Ca(phen)32 , which will form complex [Ca(phen)3(CAS)2] with CAS. In the result, the number of CAS molecules in each spot increased, causing sharp increase of the RTP signal of the CAS-phen-NaCMC system.     

强碱阴离子交换树脂及碱性洗脱剂的离子排阻/阴离子交换色谱法同时测定NH4+ ，NO2-和NO3-（英文）

Ion-exclusion/anion-exchange chromatography(IEC/AEC) on a combination of a strongly basic anion-exchange resin in the OH——form with basic eluent has been developed.The separation mechanism is based on the ion-exclusion/penetration effect for cations and the anion-exchange effect for anions to anion-exchange resin phase.This system is useful for simultaneous separation and determination of ammonium ion(NH+4),nitrite ion(NO-2),and nitrate ion(NO-3) in water samples.The resolution of analyte ions can be manipulated by changing the concentration of base in eluent on a polystyrene-divinylbenzene based strongly basic anion-exchange resin column.In this study,several separation columns,which consisted of different particle sizes,different functional groups and different anion-exchange capacities,were compared.As the results,the separation column with the smaller anion-exchange capacity(TSKgel Super IC-Anion) showed well-resolved separation of cations and anions.In the optimization of the basic eluent,lithium hydroxide(LiOH) was used as the eluent and the optimal concentration was concluded to be 2 mmol/L,considering the resolution of analyte ions and the whole retention times.In the optimal conditions,the relative standard deviations of the peak areas and the retention times of NH+4,NO-2,and NO-3 ranged 1.28%-3.57% and 0.54%-1.55%,respectively.The limits of detection at signal-to-noise of 3 were 4.10 μmol/L for NH+4,1.87 μmol/L for NO-2 and 2.83 μmol/L for NO-3.     

Statistical theory for hydrogen bonding fluid system of A_aD_d type (I): The geometrical phase transition

The influence of hydrogen bonds on the physical and chemical properties of hydrogen bonding fluid system of AaDd type is investigated from two viewpoints by the principle of statistical mechanics. In detail, we proposed two new ways that can be used to obtain the equilibrium size distribution of the hydrogen bonding clusters, and derived the analytical expression of a relationship between the hydrogen bonding free energy and hydrogen bonding degree. For the nonlinear hydrogen bonding systems, it is shown that the sol-gel phase transition can take place under proper conditions, which is further proven to be a kind of geometrical phase transition rather than a thermodynamic one. Moreover, several problems associated with the geometrical phase transition and liquid-solid phase transition in nonlinear hydrogen bonding systems are discussed.     

Resonance Light Scattering Method for Determination of Amikacin with Potassium Ferrioxalate as a Probe

In a weak acid medium, potassium ferrioxalate(PF) can react with some aminoglycoside(AGs) antibiotics, such as amikacin(AMK), kanamycin(KANA), tobramycin(TOB) and gentamicin(GEN), to form ion-association complexes. It results in the enhancement of resonance light scattering(RLS) in different degrees. The maximum scattering peaks are all located at 345 nm. Among them, the relative scattering intensity(?IRLS) of AMK system is much higher than that of KANA, TOB or GEN. Therefore the method is more propitious to the determination of trace amounts of AMK. The optimum reaction conditions, influencing factors, and the relationship between scattering intensity and concentration of antibiotics were investigated by means of the proposed method. The enhancement of RLS signals is directly proportional to the concentration of antibiotics in a certain range of concentration. A new resonance light scattering method for the determination of AMK and other aminoglycoside antibiotics with [Fe(C2O4)3]3– as a probe is thus established based on it. The method exhibits high sensitivity and good selectivity. The detection limit(3σ) for AMK is 1.8 ng/mL. The method can be applied to the determination of AMK in clinical serum samples. The reaction mechanism and the reasons for RLS enhancement are discussed in this paper.     

Impact of an ionic surfactant on the ion transfer behaviors at meso-liquid/liquid interface arrays

The influence of ionic surfactants,cetyltrimethylammonium bromide(CTAB),self-assembled within silica-nanochannels of a hybrid mesoporous silica membrane(HMSM) on simple ion transfer(IT)behaviors at the meso-water/1,2-dichloroethane(W/DCE) interface arrays supported by such a HMSM was investigated by voltammetry for the first time.Significantly,it is found that the CTAB in HMSM can dramatically enhance the peak-current responses corresponding to ITs of some anions and even lower their Gibbs transfer energies from W to DCE,which could be ascribed to an anion-exchange process between anions and the bromide of CTAB associated with partial ion-dehydration induced by the CTAB.This work will provide a new strategy to study anion transfer processes and improve the electroanalytical performance for anion detection at the liquid/liquid interface.     

Detection of Hydrazine at MXene/ZIF-8 Nanocomposite Modified Electrode

ZIF-8 with excellent chemical and physical properties is a promising material for the field of electrochemical sensing.However,the poor electrical conductivity of ZIF-8 severely limits its electrochemical performance.Here,we report a method that can significantly improve the conductivity of ZIF-8 by intercalating Ti₃C₂T_x MXene as a conductive platform.Benefiting from higher conductivity and unique electrocatalytic activity,the obtained MXene/ZIF-8 nanocomposite presented the worthy analytical performance for hydrazine sensing.The successful fabrication of MXene/ZIF-8 holds great promise for the design of electrochemical sensors,and it is a promising material to promote the development of new electrode materials.     

Synthesis and Characterization of High-purity Aluminum Titanate with Water Quenching Method

High-purity aluminum titanate was synthesized via a water quenching method with waste-residue in the aluminum factory and industrial TiO2 as the main raw materials, which belongs to the comprehensive utilization of solid wastes. Compared with the conventional method, it can reduce synthesis temperature, effectively inhibit decomposition and raise the content of AT; the addition of tiny silicon powder can improve the sintering and optimize the properties of AT. The crystalline phase structure and microstructure of each sample were characterized with XRD and SEM methods; the content of each crystalline phase in each sample was confirmed with Rietveld Quantification method; the properties of each sample were also tested. The experimental results showed that No. 4 is the optimum specimen, with the corresponding mass ratio of Al2O3/TiO2 to be 1.27 and the content of AT of 97.2 wt%. The addition of optimum tiny silicon powder is confirmed to be 8wt%; its corresponding bulk density is 2.63 g/cm^3, bending strength is 46.34 MPa, and the retention of one thermal vibration bending strength is 71.5%.     

2-Pyrrole Carboxylic Acid Nitro-Phenylamide: New Colorimetric Sensor for Anion

Due to the role played by anions in the field of biology and environmental chemistry, the development of selec tive and sensitive chemosensor for anion sensing is a topic of current attention. Colorimetric anion sensor, which does not require the use of a potentiostate or spectrometer to detect redox or optical perturbation, can give immediate qualitative anion sensing information by visual detection and therefore has advantages over other molecular sensors.According the anion binding ability of some pyrrolic amides reported by Schmuck and Gale, we linked the color reporter group of nitroanile to pyrrole moiety and synthesized two 2-pyrrole carboxylic acid nitro-phenylamides (1 and 2).