A study on the characteristics of heavy metals in orange ecosystem

An investigation was conducted to identify the characteristics of heavy metals in orange ecosystem in three areas in the Three Gorge Reservoir Region by using the modified Tessier sequential extraction procedure.The contents of Cu and Pb in different speciation fractions of the soils can be ordered as the Residual(F6)>Reducible(F4)>Oxidable(F5)>Water soluble(F1)>Carbonate(F3)>Exchangeable(F2),and the contents of Zn and Ni follow the order of the Residual(F6)>Oxidable(F5)>Reducible(F4)>Water soluble(F1)>Carbonate(F3)> Exchangeable(F2),and those of Cd follow the order of the Reducible(F4)>Oxidable(F5)>Exchangeable(F2)> Carbonate(F3)>Residual(F6)>Water soluble(F1).The concentrations of Cu in the different organs of oranges follow the increasing sequence of pulp>leaf>pericarp,those of Zn and Ni following the increasing sequence of leaf >pulp>pericarp,and those of Pb and Cd follow the increasing sequence of leaf>pericarp>pulp.Correlation degrees of different forms of same heavy metals in soils are according to the order of Cu>Zn>Cd>Pb>Ni.Correlation degrees of different heavy metals in same forms are according to the order that the forms of Reducible(F4),Oxidable(F5) and Residual(F6) are higher than the forms of Water soluble(F1),Exchangeable(F2) and Carbonate(F3).There are either positive or negative correlations between heavy metals in leaves and in pulp,while there are all positive correlations between heavy mentals in leaves and in pericarp.There are significant correlations between the concentrations of some heavy metals in leaves,pericarp or pulp,and those in speciation fractions in the soils.

Determination of Matrine and Oxymatrine in Radix Sophorae Flavescentis by Resonance Rayleigh Scattering, Second-order Scattering and Frequency Doubling Scattering Technique

In 0.1 mol/L HCl medium, 12-tungstophosphoric（TP） acid reacted with matrine（Mat） and oxymatrine（Oxy） to form an ion-association complex. As a result, the new spectra of resonance Rayleigh scattering（RRS）, second-order scattering（SOS） and frequency doubling scattering（FDS） appeared and their intensities were enhanced greatly. The maximum scattering wavelengths of RRS, SOS and FDS were located at 370, 670 and 390 nm, respectively. The in-crements of scattering intensity were directly proportional to the concentration of Mat and Oxy in a certain range. Based on this, the method for the determination of matrine and oxymatrine has been established. It has been applied to the determination of matrine and oxymatrine in samples of Radix sophorae flavescentis with satisfactory result. The reaction mechanism and reasons of RRS enhancement were discussed.

Resonance Rayleigh Scattering and Resonance Nonlinear Scattering Methods for Determination of Methylene Blue with 12-Tungstophosphoric Acid

In a pH=0.65―1.5 NaAc-HCl medium, methylene blue（MB） reacts with 12-tungstophosphoric acid （TPA） by virtue of electrostatic attraction and hydrophobic force to form a 3：2 ion-association complex. As a result, the intensities of resonance Rayleigh scattering（RRS）, second-order scattering（SOS） and frequency doubling scatte- ring（FDS） are enhanced greatly. The maximum scattering wavelengths of RRS, SOS and FDS are located at 316, 647 and 311 nm. The increments of scattering intensity（△I） are directly proportional to the concentration of MB in a certain range. The methods exhibited high sensitivity, and the detection limits（3s） for MB are 2.3 ng/mL（RRS method）, 5.6 ng/mL（SOS method） and 6.4 ng/mL（FDS method）, respectively. The effects of coexisting substances have been examined, and the results indicate that the methods have good selectivity. Based on the above researches, a new spectral method for the determination of trace amounts of MB has been developed. It can be applied to the determination of MB in human serum, and the recoveries are 97.5%―105.0%. The results are in good agreement with those obtained by the pharmacopoeia method. In this work, the optimum conditions of the reaction and the influencing factors were investigated. In addition, the reaction mechanism and the reasons of the enhancement of resonance light scattering were discussed.

Determination of Hyoscine Butylbromide with Ag＋ and Dihalogenated Fluorescein Dyes in Capsules by Resonance Rayleigh Scattering Method Coupled with Flow Injection Analysis Techniquet

In pH 4.2-5.2 HOAc-NaOAc buffer solution, Ag＋ reacted with dihalogenated fluorescein （DHF） dyes to form a 1 ; 2 anionic complex. This anionic complex could further react with hyoscine butylbromide （HBB） to form 1 ： 1 ion-association complex, which resulted in the significant enhancement of resonance Rayleigh scattering （RRS） intensity. Therefore, a novel method for the determination of HBB by resonance Rayleigh scattering （RRS） coupled with flow injection analysis （FIA） technique has been established. The present method had been applied to determine HBB in capsules and the results were in good agreement with those obtained by the literature method.