Six strawberry samples, commercially grown in Pakistan, were studied for physicochemical properties. All samples have high level of water and low contents of ash and volatile compounds. The berry was found to be a good source of potassium (1.14-1.93 g/kg), magnesium (0.12-0.15 g/kg), calcium (79.59-124.11 mg/kg) and sodium (23.51-36.03 mg/kg). The lead and cadmium contents were below the detection limits (1.0 ± 0.1 µg/l for lead and 0.1 ± 0.01 µg/l for cadmium). Principal component analysis and cluster analysis were found to be good statistical tools for the evaluation of the compositional variations with respect to geographical origin.

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The kinetics of the oxidation of xylenol orange tetrasodium salt by hydrogen peroxide was investigated in the presence of cationic surfactant (Ndodecylpyridinium chloride) & strongly basic media over the temperature range 20 -35 °C. The kinetics studies were carried out as a function of different variables like concentration, pH and temperature. The described reaction rate is greatly catalyzed by the presence of trace amount of Co(II) ions & followed pseudosecond-order with respect to dye concentration. Possible mechanism for the catalyzed and uncatalyzed reactions is proposed and found to be coincident with the experimental findings. The derived rate equation is in good agreement with the experimental observations. Thermodynamic parameters were also evaluated.

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A novel kinetic method for the determination of trace amounts of Co(II) has been developed. The proposed method based on the catalytic effect of Co(II) on the oxidation of xylenol orange tetra sodium salt by H2O2 in the presence of cationic surfactant (N-dodecylpyridinium chloride). Co(II) at mg.mL -1 was determined spectrophotometrically by measuring the decrease in the absorbance of xylenol orange at 577 nm by the differential method. The method is precise, selective, and sensitive. The detection limit of the procedure was 0.058 mg.mL -1 . The relative standard deviation for the replicate determination (n = 6) of 0.7 mg.mL -1 was 1.285%. The results compared satisfactorily with those of atomic absorption spectrometry. The method was successful for the analysis of Co(II) in veterinary and synthetic samples.