Time-based and volume-based sampling for flow-injection on-line sorbent extraction graphite furnace atomic absorption spectrometry

摘要: Abstract Fow-injection on-line preconcentration systems for graphite furnace atomic absorption spectrometry are complicated by the low eluate volume of typically less than 50 μl which can be accommodated in a tube or on platform. Even when column with an extra small capacity 15 was used, it found impossible to elute sorbed analyte completely that compatible furnace. Two approaches introducing only most concentrated fraction into while discarding rest were investigated and compared: controlling time interval collection introduction (time-based sampling), interest thin tubing fixed volume, followed this using flow air (volume-based sampling). Cadmium, copper, lead nickel elements investigated. A 15–30% greater enhancement factor obtained volume-based sampling because dispersion interrupted during sample injection segmentation. The short- long-term reproducibility also better variations pump had no influence introduced. These combined effects resulted improvement detection limits four factors 1.3–2.0. Sample throughput (23 h−1), consumption (3 ml min−1 reagent same both approaches. There significant differences accuracy precision two techniques analysis sea water, estuarine water river standard reference materials.