Patent ID: 8062899

Claim:
A method for separating, detecting and quantifying contaminants associated with L-Tryptophan induced eosinophelia-myalgia syndrome (EMS), comprising: preparing an L-Tryptophan sample; injecting the L-Tryptophan sample into a high performance liquid chromatographic (HPLC) system equipped with a column including a C18 silica-based stationary phase, wherein the C18 silica-based stationary phase comprises spherical particles; separating and eluting the EMS-associated contaminants using a gradient mobile phase program including the steps of: delivering 100% Mobile Phase A (MPA) for 10 minutes from injection of the L-Tryptophan sample; running a first linear gradient that goes from 100% MPA to a ratio of 90% MPA to 10% Mobile Phase B (MPB) at about 20 minutes from injection; running a second linear gradient that goes from a ratio of 90:10 MPA/MPB to 100% MPB at about 55 minutes from injection; detecting a presence of an EMS-associated contaminant using a UV detector set to a wavelength of about 223 nm; and quantifying at least one EMS-associated contaminant selected from the group consisting of 1,1′-Ethylidenebis L-tryptophan (EBT), 2,3-indolymethyl L-tryptophan (Peak 200), 3-anilino-L-alanine (Peak 1) and combinations thereof, wherein MPA includes about 10% acetonitrile in water with about 0.1% trifluoroacetic acid (TFA) and MPB includes about 50% acetonitrile in water with about 0.1% TFA.