Lead ultra-trace on-line preconcentration and determination using selective solid phase extraction and electrothermal atomic absorption spectrometry: applications in seawaters and biological samples.
In this work, a new chelating resin [1,5-bis (2-pyridyl)-3-sulphophenyl methylene] thiocarbonohydrazide immobilised on aminopropyl-controlled pore glass (550 A; PSTH-cpg) was synthesised and packed in a microcolumn which replaced the sample tip of the autosampler arm. The system was applied to the preconcentration of lead. When microliters of 10% HNO3, which acts as elution agent, pass through the microcolumn, the preconcentrated Pb(II) is eluted and directly deposited in a tungsten-rhodium coated graphite tube. With the use of the separation and preconcentration step and the permanent modifiers, the analytical characteristics of the technique were improved. The proposed method has a linear calibration range from 0.012 to 10 ng ml(-1) of lead. At a sample frequency of 36 h(-1) with a 90 s preconcentration time, the enrichment factor was 20.5, the detection and determination limits were 0.012 and 0.14 ng ml(-1), respectively and the precision, expressed as relative standard deviation, was 3.2% (at 1 ng ml(-1)). Results from the determination of Pb in biological certified reference materials were in agreement with the certified values. Seawaters and other biological samples were analysed too.
Vereda Alonso
E
E
Department of Analytical Chemistry, Faculty of Sciences, University of Málaga, 29071, Málaga, Spain.
Siles Cordero
M T
MT
García de Torres
A
A
Cano Pavón
J M
JM
D002138:Calibration; D002845:Chromatography / Q000379:methods*; D007854:Lead / Q000032:analysis*; D008832:Microchemistry / Q000295:instrumentation / Q000379:methods; D017942:Nitric Acid; D012117:Resins, Synthetic; D012623:Seawater; D013054:Spectrophotometry, Atomic
D012117:Resins, Synthetic; D007854:Lead; D017942:Nitric Acid