Dulcoside a

Rebaudioside A (Reb A > 97%), rebaudioside B (Reb B > 92%), rebaudioside C (Reb C > 92%), rebaudioside D (Reb D > 94%), rebaudioside F (Reb F > 94%), dulcoside A (Dul A > 93%), rubusoside (RS > 91%), steviolbioside (SB > 90%), and stevioside (SV < 96%) were purchased from the LGC Group (Middlesex, UK) at a purity of 90–97%. Acetonitrile (ACN), methanol, and water (HPLC grade) were purchased from J.T. Baker (Phillipsburg, NJ, USA). Standard solutions of the nine steviol glycosides were prepared in 30% ACN, at a concentration of 500 mg/L. One bottle of non-fermented milk and eight bottles of fermented milk were purchased from a local market and stored at 4 °C.

Standards of artificial sweeteners and steviol glycosides were obtained from different sources: acesulfame-K from Nutrinova (Frankfurt am Main, Germany); saccharine, sucralose and neohesperidin DC from Sigma-Aldrich (St. Louis, USA); aspartame from Ajinomoto Foods Europe (Nesle, France); cyclamate from Merck KGaA (Darmstadt, Germany); alitame from Frapp’s Pharma (Hong Kong, China); neotame from CHEMOS (Regenstauf, Germany); and rebaudioside A, stevioside, rebaudioside C, dulcoside A, steviolbioside and steviol from LGC Standards (Łomianki, Poland). As the internal standard (IS), sodium N-(2-methylcyclohexyl)sulfamate was used [27 (link)]. Acetonitrile (ACN), methanol (MeOH) and acetone were purchased from Merck KGaA (Darmstadt, Germany). Acetic acid (AA) was obtained from POCH (Gliwice, Poland). Ultrapure water was prepared using the HLP5 system from Hydrolab (Wiślina, Poland).