Rapid and Sensitive Chemiluminescent Enzyme Immunoassay for the Determination of Neomycin Residues in Milk

Immunoassays greatly contribute to veterinary drug residue analysis. However, there are few reports on detecting neomycin residues by immunoassay. Here, a rapid and sensitive chemiluminescent enzyme immunoassay （CLIEA） was successfully developed for neomycin residue analysis. CLIEA demonstrated good cross-reactivity for neomycin, and the IC50 value was 2.4 ng/mL in buffer.

Method for the Determination of Sudan Dyes in Foods-High Performance Liquid Chromatography Jointly Issued by AQSIQ and SAC

Sudan Red are the chemosynthesis dyes of series of azo, which are mainly used as coloring additives in ma- nufacturing of some products, such as the wax, the oil-dyes, the petrol, and etc. In the process of food production, Sudan Dyes are banned to be used as food dyes in our country.

THE DETERMINATION OF ZETA POTENTIAL IN THE COLLOID α-FeOOH/NaCl aq.BY THE APPLICATION OF STIGTER-OHSHIMA THEORIES

The electrophoretic mobility of positively charged,cylindrically shaped α-FeO OH particles dispersed in dilute sodium chloride solutions was measured at 25℃,as a function of ionic strength and pH using microelectrophoresis apparatus. The mobility data were processed through a number of selected relationships that represent various stages of understanding of electrophoretic theory,culminating in the determination of values of the electrokinetic charge and zeta potential of the colloid α-FeO OH/NaCl aq.

A COMPARISON OF THE DETERMINATION OF STABILITY CONSTANTS OF COMPLEXES OF Cd(Ⅱ)WITH AMINO ACIDS AND SIMPLE PEPTIDES USING MICRO—pH—METRIC TITRATIONS AND CYCLIC VOLTAMMETRY

This paper reports the determination of stability constants for complexes of Cd(Ⅱ)with Gly, Ala,Val,Asp,Gly—Asp,Asp Gly,Gly—Gly and Gly—Gly—Gly using both micro—pH—metric titra- tions and the application of convolution—deconvolution cyclic voltammetry at 25℃ and I=0.10 mol· dm^(-3)(KNO_3).Stability constants were calculated from pH—metric data using the SUPERQUAD com- puter program and cyclic voltammograms were collected,stored and manipulated using the EG and G CONDECON 300 software.A considerably larger ligand:metal ratio(e,g.50:1)was possible using voltammetry.Evaluation of results from the two techniques suggests that stability constants for the species[CdL_2]and[CdL_3]are reliable when calculated fromvoltammetry while those for[CdL]are more reliable when determined by pH-metric titration.

Utilization of nuclear magnetic resonance (NMR) in the determination of water status on rice seeds

The relation between seed viability and waterstatus in seed was studied.The experimentwas carried out at Zhongshan University.Seeds of hybrid rice Shanyou 63 were collectedfrom Guangdong Academy of Agriculture Sci-ences in 1993 and then stored for one year inopen air or with silica gel.Before and afterstorage,the relative content of free water andbound water in seeds were measured with

CHRONOABSORPTOMETRY FOR THE DETERMINATION OF KINETIC PARAMETERS OF ELECTRON TRANSFER REACTIONS USING LONG-OPTICAL-PATH ELECTROCHEMICAL CELL

A single potential step chronoabsorptometric method for the determination of ki- netic parameters of simple quasi-reversible reactions is described.It is verified by determining the kinetic parameters for the electroreduction of ferricyanide.A long-optical-path electro- chemical cell with a plug-in electrode is used.The thickness of solution layer is 0.55 mm

INVESTIGATION ON MICROELECTRODES Ⅻ THE DETERMINATION OF THE INVERSE CURRENT IN THE PROCESSES OF STEADY-STATE OR QUASI-STEADY-STATE

A simple method for determining the inverse current of cyclic voltammetry in the processes of steady-state or quasi-steady-state was presented. The experimental result verified the theoretical relation or inverse and forward current at microelectrode. Their ratio is proportional to the square root of scan rate.

STUDY ON THE DETERMINATION OF METRONIDAZOLE IN HUMAN SERUM BY ADSORPTIVE STRIPPING VOLTAMMETRY

In Britton-Robinson buffer,metronidazole is preconcentreted on HHDE at 0.0 V(Vs.Ag- AgCI),An adsorptive stripping peak is observed at-0.62 V.Tho response is linear from 1x10^(-8)to 1×10^(-6)mol/L with 1.5 min accumulation.The method has been successfully applied to the deternation of metronidazole in human serum and formulations.

Algorithms for the Determination of Cutsets in a Hypergraph

Given a hypergraph, this paper provides three algorithms for finding all its minimal cutsets, minimal link cutsets and the least cutsets. The result not only set up a new studying field on cutsets of hypergraph, but also lay a foundation of analyzing the performance of multibus systems. The algorithm for determining all the least cutsets in a hypergraph is polynomial complex and more efficient than that in [2].

On problem of the determination of operational mode of towed line array with distorted shape

The distortion of the array shape is one of the main factors which result the performance degeneration from the ideal situation of towed line array (TLA). Based on the ordinary array shape distortion, the directivity function of TLA is presented in this paper. An algorithm for precisely determning the coordinates of each element by means of the inverse elliptic function is derived. A fast approximation of recursive formula for solving distorted array shape is given. According to the comparison between ideal directivity and the directivity of distorted array, the criterion for making decision of operational mode of TLA sonar is presented. So that the performance prediction problem in TLA is solved. The results of system simulation in computer show a good agreement with the theoretical analysis.

NOVEL APPROACHES FOR THE DETERMINATION OF MULTIPLE PARTICULAR PESTICIDES IN TRADITIONAL CHINESE MEDICINES WITH COMPLEX MATRICES

The pesticide contamination of Traditional Chinese Medicines(TCMs)takes different ways,which caused the complexity of pesticide residues.The effective control of pesticide residues and the establishment of relevant detection methods are very important for ensuring the safety of TCMs.Our group has been committed to the determination of pesticide residues in TCMs for years.

THE EVALUATION METHODS OF VELVET ANTLER AND THE DETERMINATION OF NUCLEOSIDES AND STEROID HORMONES IN DIFFERENT PARTS FROM SIKA DEER AND RED DEER

Velvet antler is an important and precious traditional Chinese animal medicine,and was used for strengthening the kidney,anti-fatigue,improving sexual function and so on.But the evaluation methods of velvet antler and the scientific evidence for the use of antler is insufficient.Materials and Vacuum freeze drier was used for dehydration of the fresh antler at-60.,6 pa for 24 h.

A comparison of the determination of stability constants of complexes of Pb(II) with amino acids using micro-pH-metric titrations and cyclic voltammetry

This paper reports the determination of stability constants for complexes of Pb(Ⅱ) with Gly, Ala, Asp and Gly-Gly using both micro-pH-metric titrations and the application of convolution-de- convolution cyclic voltammetry at 25℃ and I = 0.10 mol.dm^(-3)(KNO_3). Stability constants were calculated from pH-metric data using the SUPERQUAD computer program and cyclic voltammograms were collected, stored and manipulated using the E G and G CONDECON 300 software. A consider- ably larger ligand: metal ratio (e.g. 50:1) was possible using voltammetry. Under these conditions, hydroxy complex formation was minimised and the formation of bis-complexes optimised. Computer based calculations were carried out on PC-compatible microcomputers fitted with mathematics co- processors. Evaluation of results from the two techniques suggests that stability constants for the species [PbL_2] are reliable when calculated from voltammetry while those for [PbL] are mote reliable when determined by pH-metric titration.

Study on the determination of trace rhenium(Ⅶ)by the adsorption differential pulse polarography

The determination of trace rhenium(Ⅶ)by differential pulse polarography in the system of H_2SO_4-(NH_2OH)_2·H_2SO_4-TeO_4^(2-) is markedly improved by the addition of Nitron,which is adsorbed on the surface of mercury electrode.The limit of detection is down to 2×10^(-10) M.The adsorptive peak potential is -0.80V(vs.SCE).In the ranges of 5×10^(-10)-10^(-8),1×10^(-8)-10^(-7) and 1× 10^(-7)-10^(-6)M,there are good linear relationships between the peak current increment and the concentration,of which the relative standard deviations are 9.5,6.6,1.8% respectively with the correlation coefficients of linear regression of 0.995—0.999.The results relating to this polarographic wave show that it is an adsorption-catalytic wave.The mechanism of the electrode reaction is dis- cussed.

The determination of the crystal struoure of tetra-potassium uranyl tricarbonate by powder X-ray diffraction method

A uranyl compound, K_4UO_2(CO_3)_3 has been characterized by powder X-ray diffraction method. M. W.=606.46, monoclinic, C2/c (No. 15), a=1.0240(7), b=0.9198(4), c=1.2222(12)nm, β=95.12(4)°,V=1.1466(5)nm^3, Z=4, D_m=3.468g/cm^3, D_c=3.513g/cm~, λ(Cu Kα_1)=O.1540598nm, T=298K. The structure was solved by heavy atom method and Fourier synthesis, and refined by full- matrix least-squares method to R=0.1185 for 275 reflections. The uranium (Ⅵ) atom is in an eight-coordinate distorted hexagonal-bipyramidal environment with creasy fan shape. The linear uranyl group approaches to perpendicular to the equatorial plane in which three carbonate groups are chelated. U(Ⅵ) has two linear oxygen atoms closer to it (U-O=0.1767 (5) nm) than six other neighbours (U-O ranging from 0.2516 to 0.2568nm). The distances between carbon atoms and uncoordinated oxygen atoms are 0.122 (1) and 0.123(1) nm, which are distinctly different from those between carbon and coordinated oxygen atoms (mean 0.134(6) nm). This fact reveals the non-eq- uivalence of one oxygen atom to the other two in each carbonate. In K_4UO_2(CO_3)_3, the O-O dis- tance for the adjacent carbonate groups is 0.2794(4)nm approaching to the sum of Van der Waals radii of two oxygen atoms. The K-O distances vary between 0.2667 and 0.3131nm, and each anion is immediately surrounded by six potassium ions, only four of which can be considered to belong to the same structural formula unit, and they are symmetrically located above and below the equatorial plane.