Flow injection on-line sorbent extraction pre-concentration for graphite furnace atomic absorption spectrometry

摘要: Flow injection (FI) techniques were used to develop an efficient on-line sorbent extraction pre-concentration system for graphite furnace atomic absorption spectrometry with lead as a model trace element. Bonded silica octadecyl functional groups (C18) was in 15-µl conically shaped micro-column. The diethyldithiocarbamate chelate formed on-line, loaded on the column 60 s, washed de-ionised water and eluted ethanol into collector volume of 75 µl, made from 0.35 mm i.d. polytetrafluoroethylene tubing. collected eluate introduced tube by air flow initiation FI next sample. reproducibility peak gradients exploited through precise timing collection fraction so that end sections bolus containing lower analyte concentrations discarded. A 26-fold enhancement area compared 50 µl direct introduction obtained 60-s while achieving precision 1.9% relative standard deviation 0.1 µg l–1 Pb (n= 11), detection limit 0.003 l–1(3σ). complete cycle operation 150 s which conveniently fitted time interval between successive firings. Determination sea samples showed interfering matrix had been almost completely removed during pre-concentration, determinations without using chemical modifiers. Results National Research Council Canada Standard Reference Materials CASS 1, 2 [Seawater (Coastal)] NASS 1 (Open Ocean)] matrix-matched standards SLRS Riverine Water simple aqueous agreed well certified values.