with co-precipitation method using a triazole

A new co-precipitation method was developed to separate and pre-concentrate Fe3+, Cu2+, Cr3+, Zn2+, and Pb2+ ions using an organic co-precipitant, 3-benzyl-4-p-nitrobenzylidenamino-4,5-dihydro1,2,4-triazole-5-on (BPNBAT) without adding any carrier element, following flame atomic absorption spectrometric (FAAS) determinations. Effect of some analytical conditions, such as pH of the solution, quantity of the co-precipitant, standing time, centrifugation rate and time, sample volume, and interference of concomitant ions were investigated over the recovery yields of the metal ions. The recoveries of the analyte ions were in the range of 95-102%. The detection limits, corresponding to three times the standard deviation of the blank, were found to be in the range of 0.3-2.0 mu g L-1. The precision of the method, evaluated as the relative standard deviation (R.S.D.) obtained after analyzing a series of 10 replicates, was between 1.6% and 6.0% for the trace metal ions. The method was validated by analyzing two certified reference materials and spiked addition. The proposed procedure was applied for the trace metal ions in some environmental samples. (C) 2008 Elsevier B.V. All rights reserved

aqueous solutions

A separation/preconcentration procedure, based on the coprecipitation of Cr(3+), Fe(3+), Pb(2+) and Zn(2+) ions using a new organic coprecipitant, 3-phenly-4-o-hydroxybenzylidenamino-4,5-dihydro-1,2,4-triazole, 5-one (POHBAT) without adding any carrier element has been developed The method thus has been.,, called carrier element-free coprecipitation (CEFC). The resultant concentrated elements were determined by flame atomic absorption spectrometric determinations. The influences of some analytical parameters including pH of the solution, amount of the coprecipitant, standing time, centrifugation rate and time, sample volume and diverse ions were investigated on the quantitative recoveries of analyte ions. The validation of the present preconcentration procedure was performed by the analysis of two certified reference materials. The recoveries of understudy analytes were found in the range of 93-98%, while the detection limits were calculated in the range of 0.3-2.0 mu g L(-1). The precision of the method evaluated as relative standard deviation (R.S.D.), was in the range of 3-7% depend on the analytes. The proposed method was successfully applied to environmental samples for the determination of the analytes. (C) 2008 Elsevier B.V. All rights reserved

complexing with 8-hydroxyquinoline

A procedure for preconcentration of Mn(H), Fe(II), Co(II), Cu(II), Cd(II), Zn(II), Pb(II) and Ni(II) based on retention of their complexes with 8-hydroxyquinoline (HQ) on Amberlite XAD-2000 resin in a column was proposed for the analysis of environmental samples by flame AAS. Various parameters such as pH, eluent type, volume, concentration, flow rate and volume of sample solution, and matrix interference effect on the retention of the metal ions were investigated. The optimum pHs for the retention of metal complexes in question were about 6 except for Mn2+ for whose value is 8. The loading capacity of the adsorbent for these metals and their recoveries from the resin under the optimum conditions were in the range 6.82-9.26 mg.g(-1) and 95%-101%, respectively. The enrichment factor was calculated as 100 and the limit of detection was in the range 0.3-2.2 mu g.L-1 (n=20, blank + 3s). The proposed enrichment method was applied to tap water, stream water and vegetable samples. The validation of the procedure was carried out by analysis of certified reference material and standard addition. The analytes were determined with a relative standard deviation lower than 6% in all samples

Surface water chemistry and nitrate pollution in Shimabara, Nagasaki, Japan

Groundwater is a finite resource that is threatened by pollution all over the world. Shimabara City, Nagasaki, Japan, uses groundwater for its main water supply. During recent years, the city has experienced severe nitrate pollution in its groundwater. For better understanding of origin and impact of the pollution, chemical effects and surface?groundwater interactions need to be examined. For this purpose, we developed a methodology that builds on joint geochemical analyses and advanced statistical treatment. Water samples were collected at 42 sampling points in Shimabara including a part of Unzen City. Spatial distribution of water chemistry constituents was assessed by describing Stiff and Piper diagrams using major ions concentrations. The nitrate (NO3 + NO2?N) concentration in 45% of water samples exceeded permissible Japanese drinking level of 10 mg L? 1. Most of the samples showed Ca?HCO3 or Ca?(NO3 + SO4) water types. Some samples were classified into characteristic water types such as Na?Cl, (Na + K)?HCO3, (Na + K)?(SO4 + NO3), and Ca?Cl. Thus, results indicated salt water intrusion from the sea and anthropogenic pollution. At the upstream of Nishi River, although water chemistry was characterized as Ca?HCO3, ion concentrations were higher than those of other rivers. This is probably an effect of disinfection in livestock farming using slaked lime. Positive correlation between NO3 ? and SO4 2?, Mg2+, Ca2+, Na+, K+, and Cl? (r = 0.32?0.64) is evidence that nitrate pollution sources are chemical fertilizers and livestock waste. Principal component analysis showed that chemistry of water samples can be explained by three main components (PCs). PC1 depicts general ion concentration. PC2 and PC3 share influence from chemical fertilizer and livestock waste. Cluster analyses grouped water samples into four main clusters. One of these is the general river chemistry mainly affected by PC1. The others reflect anthropogenic activities and are identified by the combination of the three PCs