Nylon fh membranes

Acetic acid was from Normasolv (Barcelona, Spain), ammonium acetate, and ammonium hydroxide were from Panreac (Barcelona, Spain), and ethanol of analytical grade was acquired from Lab-Scan (Gliwice, Poland). Acetonitrile (ACN) and formic acid (HPLC-MS grade) were obtained from Fisher-Scientific (Fair Lawn, NJ, USA). ESI-TOF Low Concentration Tuning Mix G1969-85000 was acquired from Agilent Technologies (Santa Clara, CA, USA). Nanopure water (18.2 MΩ·cm, 25 °C) was used throughout all experiments.
Analytical grade standards of 6′-sialyllactose (6′-SL) sodium salt, 3′-sialyllactose (3′-SL) sodium salt, 3′-sialyl-N-acetyllactosamine, 3′-galactosyl-lactose, 4′-galactosyl-lactose, and 6′-galactosyl-lactose were purchased from Carbosynth (Berkshire, UK), whereas 3α,4β-galacto-triose was obtained from Dextra Laboratories (Reading, UK) and 2′-fucosyllactose (2′-FL) was from V-Laboratories (Covington, LA, USA). Nylon FH membranes (0.22 μm; Millipore, Bedford, MA, USA) were used for filtering ACN:water (50:50, v:v) standard solutions before injection.

All reagents were of analytical grade or better. Acetic acid from Normasolv (Barcelona, Spain), ammonium acetate, ammonium hydroxide from Panreac (Barcelona, Spain) and ethanol of analytical grade were purchased from Lab-Scan (Gliwice, Poland). Acetonitrile (ACN) and formic acid HPLC-MS grade were purchased from Fisher-Scientific (Fair Lawn, NJ, USA). ESI-TOF Low concentration Tuning Mix G1969–85000 was purchased from Agilent Technologies (Santa Clara, CA, USA).
Analytical standards of β-4-galactosyl-lactose, maltotriose and maltotetraose were obtained from Sigma Chemical Co. (St. Louis, MO, USA). 6′-Sialyl-lactose (6′-SL) sodium salt, 3′-sialyl-lactose (3′-SL) sodium salt, 2′-fucosyl-lactose (2′-FL) and 3′-sialyl-N-acetyllactosamine were purchased from Carbosynth (Berkshire, UK). Standard solutions in ACN:water (50:50, v:v) were filtered through nylon FH membranes (0.22 µm; Millipore, Bedford, MA, USA) before injection.