HPLC grade water (PubChem CID: 962), acetonitrile (PubChem
CID: 6342), trifluoroacetic acid (TFA) (PubChem CID: 6422),
aspartyl-phe methyl ester (aspartame) and a neotame standard
were procured from Sigma–Aldrich (Layoffs, Missouri, USA). LAspartyl-
L-phenylalanine was from Sigma–Aldrich (Steinheim,
Germany). HPLC grade dipotassium hydrogen orthophosphate
(PubChem CID: 24450) and potassium dihydrogen orthophosphate
(PubChem CID: 516951) were from Qualigens Fine Chemicals
(Mumbai, India).