Flame photometry (Sherwood Scientific Ltd., Model 410, Cambridge, UK) was used to evaluate sodium concentration, sodium standards (0e1 mL/L) were prepared for calibration. The calibration
curve demonstrated repeatability (R2 > 0.99), and linearity up to 1 mL/L, wavelength 589 nm. The sodium data was collated in triplicate and converted to sodium chloride concentration (2.5).