Selective detection of trace lead in lead-free solder alloy by flow injection on-line solid-phase extraction using a macrocycle immobilized silica gel as sorbent coupled with hydride generation atomic fluorescence spectrometry

As lead-free solder is a tin-based alloy, and contains large amounts of tin, copper or other metals that can cause serious interferences with hydride generation, accurate determination of trace lead in lead-free solder by hydride generation atomic. uorescence spectrometry ( HG- AFS) is challenging. In this work, a flow injection ( FI) on- line solid phase extraction ( SPE) technique was coupled to HG- AFS for selective determination of lead in lead-free solder. Macrocycle immobilized silica gel with high selectivity for lead was employed as the sorbent to eliminate interferences from other heavy metals and hydride-forming elements on HG- AFS determination of lead. At least 500 mg L-1 of Cu( II), Fe( III), Ni( II), Zn( II), Cr( II), Ca( II), Al( III), Cd( II), Co( II) and Ag( I), 200 mg L-1 of Sn( II), 100 mg L-1 of As( III), Hg( II), Se( IV) and Sb( III), and 50 mg L-1 of Ba( II) had no interferences on the determination of 0.5 mg L-1 Pb( II). With a sample loading. ow rate of 4.8 mL min(-1) for 60 s on- line SPE, a detection limit ( 3s) of 3 ng L-1 and an enhancement factor of 61 was obtained. The precision ( RSD, n = 11) was 1.8% at the 0.5 mg L-1 Pb( II) level. The developed method allows cost-effective, sensitive, accurate and interference- free determination of trace lead in lead- free solder samples.