Fully automatic system for lead monitoring in water

A fully automatic multisyringe flow injection analysis - lab on valve system (MSFIA-LOV) with assisted automatic stirring for Pb (II) determination exploiting a long path-length liquid waveguide capillary cell (LWCC) for spectrophotometric detection was developed. On-line extraction of lead was performed inside of a microcolumn using a selective solid phase extraction (PB-resin), followed by the Pb-PAR complex formation with 4-(2-pyridylazo) resorcinol (PAR) as chromogenic reagent, to obtain a spectrophotometric detection at 520 nm. The assistance of automatic mechanical agitation to increase the analytical signal was made by using a rotary motor whose movement through a stainless steel rod, allowed to form a submersible agitator device. The limit of detection (LOD) of the developed method is 0.79 mu g L-1, allowing the analysis well below the guideline values for lead in drinking water. The analytical parameters achieved, such as the good precision (RSD 4.2%), the analysis frequency and its fully automation make of this method a portable tool for low-cost Pb (II) detection system for water samples. The method has been successfully validated by means of a groundwater certified reference material (BCR (R)-610). It was also applied to different water matrices (groundwater, commercial bottled water and tap water) with recoveries close to 100%.