Experimental techniques to minimize loss of iron and sodium from sample materials in experiment using one atmosphere gas mixing furnace are proposed. Melting experiments for basaltic synthetic materials and natural basalts and andesites were carried out at 1150∼1250°C and oxygen fugacities from air to ΔNNO=−5.0. Based on the results of present experiments and previous works, the folowing empirical relationships were derived. Relationship between iron content of platinum loop (X_Fe^{FePt alloy}) and FeO contenlt in silicate liquid (X_{Total FeO}^Liquid) was described by

      X_Fe^{FePt alloy}(wt%)=(1.782-0.0908X_{Total FeO}^Liquid(wt%))logf_O2+0.2574logf_O2²        (1).

Correlation among Na₂O loss from liquid (Y) and oxygen fugacity, run duration (t), mass of liquid (W), temperature (T) and chemical composition was described by

      ln[−ln(1−Y(%)/100)]=18.66+2.145×(FeO+MnO+MgO+CaO)/SiO₂(mole ratio) −0.225ln f_O2−416800/RT(K)−1/3×lnW(mg)+lnt(min)        (2).

     Melting experiments using iron-plated platinum loop whose iron content was calculated from equation (1) and setting Na₂SiO₃ liquid below the sample were also performed. Loss of FeO and Na₂O from sample materials could be reduced considerably by the iron-plated platinum loop and Na₂SiO₃ liquid. In experiments of iron partitioning in alkaline rich system at reducing oxygen fugacity, continuous change of bulk chemical composition and disequilibrium can be minimized by these techniques.