Rapid simultaneous determination of arginine and methylated arginines in human urine by high-performance liquid chromatography-mass spectrometry

A simple, sensitive and fast method using reversed-phase high-performance liquid chromatography (HPLC)-mass spectrometry (MS) coupling with an atmospheric pressure chemical ionization (APCI) interface was developed for simultaneous separation and determination of (L)-arginine (ARG), N-G,N-G-dimethylarginine (ADMA) and 0,1VI-dimethylarginine (SDMA) inhuman urine. This method involved the use of the [M+H](+) ions of ARG, ADMA and SDMA at m/z 175,203 and 203 in the selective ion monitoring (SIM) mode. Satisfactory separation was achieved on a 2.0 mm x 150 nun Shimadzu VP-ODS column by using the mobile phase consisting of water (95%), acetonitrile (5%) and trifluoroacetic acid (TFA, 0.4%). (L)-Homoarginine was used as the internal standard for the assay. With an isocratic HPLC, the total LC-APCI-MS analysis time was less than 5 min, making the method the fastest and most specific method reported to date. The limits of quantification (LOQ) were found to be 0.2 mumol 1(-1) for AG, ADMA and SDMA. The inter-assay precision and accuracy were in the range of 2.1-6.8 and -4.4-5.4%, respectively. The intra-assay precision and accuracy were in the order of 1.6-4.1 and -1.8-3.2%, respectively. The recoveries were between 98.2 and 103.2%. With the help of the proposed method, the levels of ARG, ADMA and SDMA in human urine were determined. (C) 2003 Elsevier B.V. All rights reserved.