Quantification of common anions in bottled drinking water according to EPA method 300.1A

Quantitative analysis of anions in bottled spring water according to the method US EPA 300.1A using a Shodex IC SI-50 4E column (250×4 mm) and an eluent containing 3.2 mM Na₂CO₃ and 1.0 mM NaHCO₃ in ultra-pure water pumped at 0.7 mL/min at 30 °C from an EQAX-B1 eluent bottle equipped with an EQAX-TC1 trap cartridge for carbon dioxide removal. Background reduced to ~21 µS/cm by XAMS suppressor with ASUREX-A200 automatic regenerator. Eluent pumping and conductivity detection by an inert Shimadzu Prominence system with modules CMB-20A, 2x LC-20Ai, DGU-203R, SIL-20AC, CTO-20A, and CDD-10Avp. Injection of 50 µL sample. Linear six-point calibration curves at different ranges for different ions (two orders of magnitude between 0.01 to 100 mg/L) gave the following concentrations after dilution to fit into the calibration ranges when required; F¯ 1.1 mg/L (ppm), Cl¯ 46 mg/L, NO₃¯ 1.6 mg/L and SO₄²¯ 23 mg/L.