Feasibility of using in situ fusion for the determination of Co,Cr and Mn in Portland cement by direct solid sampling graphite furnace atomic absorption spectrometry

In situ fusion on the boat-type graphite platform has been used as a sample pretreatment for the direct determination of Co, Cr and Mn in Portland cement by solid sampling graphite furnace atomic absorption spectrometry (SS-GF AAS). The 3-field Zeeman technique was adopted for background correction to decrease the sensitivity during measurements. This strategy allowed working with up to 200 µg of sample. The in situ fusion was accomplished using 10 µL of a flux mixture 4.0% m/v Na₂CO₃ + 4.0% m/v ZnO + 0.1% m/v Triton® X-100 added over the cement sample and heated at 800 °C for 20 s. The resulting mould was completely dissolved with 10 µL of 0.1% m/v HNO₃. Limits of detection were 0.11 µg g^− 1 for Co, 1.1 µg g^− 1 for Cr and 1.9 µg g^− 1 for Mn. The accuracy of the proposed method has been evaluated by the analysis of certified reference materials. The values found presented no statistically significant differences compared to the certified values (Student's t-test, p < 0.05). In general, the relative standard deviation was lower than 12% (n = 5).