Determination of rare earth elements in biological samples by inductively coupled plasma mass spectrometry

A method for the determiantion of rare earth elements in biological sampels by inductively coupled plasma mass spectrometry was developed. Oxide ion yield of the rare earth elements (RFE) decreased with the increasing of RF power and the sampling depth, or with the decreasing of carrier gas flow rate. The spectral interference arising from (PrO)-Pr-141-O-16 on Gd-157 must be corrected. if the concentration of Ba was high enough, it was necessary to correct the spectral interference arising from (BO)-B-135-O-16 on Eu-151, and it was not necessary to correct spectral interference arising from (NdO)-Nd-143-O-16 on Tb-159 etc. in the biological samples under the selected operation parameters. In the biological sample, the major matrix elements, such as K, Na and Ca, result in the suppression of REEs signals and the suppression degree of the Ca is grezter than that of the K and Na. The mussel sample was digested by thd dry ashing, wet digestion with HNO3 + H2O2 and HNO3 + HClO4, respectively. The analytical results of REEs were consistent with each other. Detection limits for REEs are 0.001 similar to 0.013 mu g/L. Recoveries of standard addition are 91.7% similar to 125%. REEs in biological samples were determined directly without separation and preconcentration procedure.

Identification of vhhP2, a novel genetic marker of Vibrio harveyi, and its application in the quick detection of V. harveyi from animal specimens and environmental samples

Aims: To investigate the species-specific prevalence of vhhP2 among Vibrio harveyi isolates and the applicability of vhhP2 in the specific detection of V. harveyi from crude samples of animal and environmental origins. Methods and Results: A gene (vhhP2) encoding an outer membrane protein of unknown function was identified from a pathogenic V. harveyi isolate. vhhP2 is present in 24 V. harveyi strains isolated from different geographical locations but is absent in 24 strains representing 17 different non-V. harveyi species, including V. parahaemolyticus and V. alginolyticus. A simple polymerase chain reaction method for the identification of V. harveyi was developed based on the conserved sequence of vhhP2. This method was demonstrated to be applicable to the quick detection of V. harveyi from crude animal specimens and environmental samples. The specificity of this method was tested by applying it to the examination of two strains of V. campbellii, which is most closely related to V. harveyi. One of the V. campbellii strains was falsely identified as V. harveyi. Conclusions: vhhP2 is ubiquitously present in the V. harveyi species and is absent in most of the non-V. harveyi species; this feature enables vhhP2 to serve as a genetic marker for the rapid identification of V. harveyi. However, this method can not distinguish some V. campbellii strains from V. harveyi. Significance and Impact of the Study: the significance of our study is the identification of a novel gene of V. harveyi and the development of a simple method for the relatively accurate detection of V. harveyi from animal specimens and environmental samples.

Simultaneous determination of four phases of copper in geological samples

According to the specific property of respective phases in copper ore, optimal extracting condition for, tour phases of copper with five infusion was examined. After a series of experiments, for example, different weight Of sample, artificial mixed single phases sample and repeated experiment, the extracting ratio constants foil all phases in different infusions were obtained. The mathematical model which is on the basis of the stable extracting constant is established. Based on the purpose-control genetic algorithms, we only need to determine the total copper in the sample in different infusions under the selected condition, then the value of respective phase could be calculated. The-relative standard deviation are (%) free oxidized copper phase:1.5, conjunction oxidized copper phase: 17.6,, secondary copper sulfide phase: 1.9, primary copper sulfide phase : 2.7,total copper: 0.8.

Recovery of protein from discharged wastewater during the production of chitin

Studies were carried out to optimize the conditions for the recovery of protein. The results showed that pH of 6.00 for wastewater, the dosage of 1% chitosan solution in 1% acetic acid aqueous solution of 2.0 ml for 50 ml wastewater and 1% FeCl3 aqueous solution of 2 ml for 50 ml wastewater, the flocculation time of 4.0 h were the optimal conditions for the recovery of protein. The obtained protein sediment contained abundant amino acids, especially isoleucine, methione and lysine that are absent in other protein resource. (c) 2007 Elsevier Ltd. All rights reserved.

Biosorption and desorption of Cd2+ from wastewater by dehydrated shreds of Cladophora fascicularis

The adsorption and desorption of algae Cladophora fascicularis and their relation with initial Cd2+ concentration, initial pH, and co-existing ions were studied. Adsorption equilibrium and biosorption kinetics were established from batch experiments. The adsorption equilibrium was adequately described by the Langmuir isotherm, and biosorption kinetics was in pseudo-second order model. The experiment on co-existing ions showed that the biosorption capacity of biomass decreased with an increasing concentration of competing ions. Desorption experiments indicated that EDTA was efficient desorbent for recovery from Cd2+. With high capacities of metal biosorption and desorption, the biomass of Cladophora fascicularis is promising as a cost-effective biosorbent for the removal of Cd2+ from wastewater.

Sorption and desorption of lead (II) from wastewater by green algae Cladophora fascicularis

Biosorption is an effective method to remove heavy metals from wastewater. In this work, adsorption features of Cladophora fascicularis were investigated as a function of time, initial pH, initial Pb(II) concentrations, temperature and co-existing ions. Kinetics and equilibria were obtained from batch experiments. The biosorption kinetics followed the pseudo-second order model. Adsorption equilibria were well described by the Langmuir and Freundlich isotherm models. The maximum adsorption capacity was 198.5 mg/g at 298 K and pH 5.0. The adsorption processes were endothermic and the biosorption heat was 29.6 kJ/mol. Desorption experiments indicated that 0.01 mol/L Na(2)EDTA was an efficient desorbent for the recovery of Pb(II) from biomass. IR spectrum analysis suggested amido or hydroxy, C=O and C-O could combine intensively with Pb(II). (C) 2006 Elsevier B.V. All rights reserved.

Synthesis and evaluation of a thiourea-modified chitosan derivative applied for adsorption of Hg(II) from synthetic wastewater

In this work, a thiourea-modified chitosan derivative (TMCD) was synthesized through two steps, O-carboxymethylated first and then modified by a polymeric Schiff's base of thiourea/glutaraldehyde. The adsorption behavior of mercury (II) ions onto TMCD was investigated through batch method. The maximum adsorption capacity for Hg(II) was found to be 6.29 mmol/g at pH 5.0 and both kinetic and thermodynamic parameters of the adsorption process were obtained. The results indicated that adsorption process was spontaneous exothermic reaction and kinetically followed pseudo-second-order model. The adsorption experiments also demonstrated TMCD had high adsorption selectivity towards Hg(II) ions when coexisted with Cu(II), Zn(II), Cd(II) and Ca(II) in solution and it could be easily regenerated and efficiently reused. (C) 2010 Elsevier B.V. All rights reserved.

2-(2-Phenyl-1H-phenanthro-[9,10-d]imidazole-1-yl)-acetic acid (PPIA) and its application for determination of amines by high performance liquid chromatography with fluorescence detection and identification with mass spectroscopy/atmospheric pressure chemical ionization

A simple, sensitive, and mild method for the determination of amino compounds based on a condensation reaction with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC-HCI) as the dehydrant with fluorescence detection has been developed. Amines were derivatized to their acidamides with labeling reagent 2-(2-phenyl-1H-phenanthro-[9,10-d]imidazole-1-yl)-acetic acid (PPIA). Studies on derivatization conditions indicated that the coupling reaction proceeded rapidly and smoothly in the presence of a base catalyst in acetonitrile to give the corresponding sensitively fluorescent derivatives with an excitation maximum at lambda(ex) 260nm and an emission maximum at lambda(em) 380nm. The labeled derivatives exhibited high stability and were enough to be efficiently analyzed by high-performance liquid chromatography. Identification of derivatives was carried out by online post-column mass spectrometry (LC/APCI-MS/MS) and showed an intense protonated molecular ion corresponding m/z [MH](+) under APCI in positive-ion mode. At the same time, the fluorescence properties of derivatives in various solvents or at different temperature were investigated. The method, in conjunction with a gradient elution, offered a baseline resolution of the common amine derivatives on a reversed-phase Eclipse XDB-C-8 column. LC separation for the derivatized amines showed good reproducibility with acetonitrile-water as mobile phase. Detection limits calculated from 0.78 pmol injection, at a signal-to-noise ratio of 3, were 3.1-18.2 fmol. The mean intra- and inter-assay precision for all amine levels were < 3.85% and 2.11%, respectively. Excellent linear responses were observed with coefficients of > 0.9996. The established method for the determination of aliphatic amines from real wastewater and biological samples was satisfactory. (c) 2006 Elsevier B.V. All rights reserved.

Peak identification for PCDD/Fs in environmental samples at different temperature programs

A method has been developed for peak recognition of 136 polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) at different temperature programs. Their retention behaviours are predicted on the basis of an identification database of retention values (A, B) of gas chromatography. By the retention times of C-13 labelled 2,3,7,8-substituted PCDD/F internal standards, the retentions of all PCDDs and PCDFs can be calculated. After comparison with the retentions of practical environmental samples, the predicted values have been proved to be very accurate. (C) 2000 Elsevier Science Ltd. All rights reserved.