An on-line pre-concentration system for determination of cadmium in drinking water using FAAS

Abstract

In the present paper, a minicolumn of polyurethane foam loaded with 4-(2-pyridylazo)-resorcinol (PAR) is proposed as pre-concentration system for cadmium determination in drinking water samples by flame atomic absorption spectrometry. The optimization step was performed using two-level full factorial design and Doehlert matrix, involving the variables: sampling flow rate, elution concentration, buffer concentration and pH. Using the established experimental conditions in the optimization step of: pH 8.2, sampling flow rate 8.5 mL min(-1), buffer concentration 0.05 mol L(-1) and elution concentration of 1.0 mol L(-1), this system allows the determination of cadmium with detection limit (LD) (3sigma/S) of 20.0 ng L(-1) and quantification limit (LQ) (10sigma/S) of 64 ng L(-1), precision expressed as relative standard deviation (R.S.D.) of 5.0 and 4.7% for cadmium concentration of 5.0 and 40.0 microg L(-1), respectively, and a pre-concentration factor of 158 for a sample volume of 20.0 mL. The accuracy was confirmed by cadmium determination in the standard reference material, NIST SRM 1643d trace elements in natural water. This procedure was applied for cadmium determination in drinking water samples collected from Salvador City, Bahia, Brazil. For five samples analyzed, the achieved concentrations varied from 0.31 to 0.86 microg L(-1).

Application of chloromethylated polystyrene functionalized with N,N-bis(naphthylideneimino)diethylenetriamine in an on-line preconcentration system for the determination of cadmium by FAAS

“…Some advantages of polymeric solid supports include low cost, simple preparation, high porosity and thus highly available surface area, and stability in acidic or basic media. Some polymeric solid supports such as amberlite XAD-2 [24,25], XAD-4 [26], polyurethane foam (PUF) [27][28][29], and grafted poly(tetrafluoroethylene) (PTFE) [30] have been used for preconcentration and determination of cadmium by FAAS. For a comparative study, the analytical merits data from some reported SPE methods for FAAS determination of cadmium are given in Table 1.…”

Applications of Amberlite XAD based Chelating resins in Online Pre concentration of metal ions

“…The chelating resins can be used in flow injection system with various detection methods like FAAS, ICP-AES, spectrophotometry, chemiluminescence and ICP-MS etc [26].There are various chelating resins have recently been used such as polyurethane foam [27][28][29][30][31][32][33][34][35], cellulose, silica gel [36][37][38][39][40][41][42], alumina [43][44][45][46][47][48], chitosan [49][50][51], carbon active [52] and polymeric resins like Amberlite etc. Amberlite XAD resins widely used to develop several chelating materials for preconcentration procedures due to its good physical and chemical properties such as porosity, high surface area, durability and purity.…”

Development of a coprecipitation system for the speciation/preconcentration of chromium in tap waters

“…In recent years, several methods of preconcentration and separation of chromium(III) and chromium(VI) have been developed [9][10][11][12][13][14][15][16]. Instrumental analysis methods including atomic absorption spectrometry and inductively coupled plasma mass spectrometry always request previous steps of several separation-preconcentration procedures including solid phase extraction, ion exchange, cloud point extraction have been performed as separation technique [17][18][19][20][21].…”