Evaluation of Pb-Spec® for flow-injection solid-phase extraction preconcentration for the determination of trace lead in water and wine by flame atomic absorption spectrometry

Abstract

Two manifold designs were evaluated. Water samples and wine digests in 10% nitric acid were pumped through a column containing a commercially available resin (Pb-Spec ® ), an immobilized crown ether with a cavity size selective for Pb 2+ . The column was rinsed with 2% HNO 3 and the eluent, 0.1 mol l −1 ammonium oxalate was injected via a six-port rotary valve. The eluted lead was delivered to the flame atomic absorption spectrometer at 4.0 ml min −1 . The following flow-injection (FI) parameters were optimized: sample acidity and volume, loading and elution flow rates, and eluent composition and volume.The detection limit for the water samples, estimated from the noise on the signal obtained for 250 ml of 10 g l −1 loaded at 19.1 ml min −1 was 1 g l −1 . For 50 ml of wine digest loaded at 4 ml min −1 , the value was 3 g l −1 . The roles of loading flow rate and sample volume were investigated in detail. The variation in retention efficiency with loading flow rate showed that the amount of lead retained (during a fixed loading time) increased with flow rate until the upper performance limit of the peristaltic pump was reached. The variation of detection limit with sample volume followed the expected hyperbolic relationship and showed that only small improvements in LOD were obtained for volumes greater than 50 ml. The method was evaluated through spike recovery for both water and wine. The lead contents of tap (0.24 g l −1 ), pond (0.40 g l −1 ), and river waters (not detected) were determined. The concentrations of lead in three Port wine samples ranged from not detected to 190 g l −1 . No significant matrix suppression effects were observed.

A Simple and Sensitive Flow-Injection On-line Preconcentration Coupled with Hydride Generation Atomic Fluorescence Spectrometry for the Determination of Ultra-trace Lead in Water, Wine, and Rice

“…The detection limit was found to be 16 ng l -1 with the linear range of method between 0.05 and 10 μg l -1 . Compared with some reported methods for atomic spectrometric determination of lead in foods and drinks, the sensitivity of the proposed system is not only greatly improved with respect to those of conventional HG-AAS, 22,25 HG-ICP-OES 26 and ICP-MS, 27 but also superior to those preconcentration systems with FAAS, 4,8,10 ICP-AES 9 and ETAAS. 11 The effect of foreign substances Minimization of transition-metal interferences.…”

Selective separation of elements from complex solution matrix with molecular recognition plus macrocycles attached to a solid-phase: A review

“…Furthermore, the macrocycle-immobilized Pb-selective SPEs have been successfully applied for the separation/preconcentration of lead from biological and environmental samples [132,134,[136][137][138][139][140].…”

Determination of thallium traces by ETAAS after on-line matrix separation and preconcentration in a flow injection system

“…[23][24][25][26] The commercially available immobilized crown ether (Pb-Spec and Sr-Spec resin) has been used for preconcentration of lead in various matrices. 27,28 The physical immobilization of crown ether on the knotted reactor has been also used for preconcentration and separation of palladium in tunnel dust. 29 However, to the best of our knowledge, reports on physical immobilization of crown ethers on solid supports used as the sorbent for preparation of column or microcolumn of solid phase extraction of metal ions is rare.…”