sample_id,description,ion_measured,concentration_mol_per_L
S1,lemon juice,H+,2.5e-3
S2,black coffee,H+,1.3e-5
S3,distilled water,H+,1.0e-7
S4,milk,H+,3.9e-7
S5,seawater,OH-,7.9e-6
S6,baking soda solution,OH-,1.0e-5
S7,ammonia cleaner,OH-,4.8e-3
S8,stomach acid,H+,6.3e-2