Masstrak amino acid analysis solution aaa kit

The metabolomics method for analyzing these serum samples using LC-MS/MS has been described previously^{28 (link)}. Briefly, serum amino acid calibration standards were prepared with a MassTrak Amino Acid Analysis Solution (AAA) kit (Waters Corp, Milford, MA) according to instructions with slight modifications for detection on a mass spectrometer^{40 (link)}. To measure accurate metabolite concentrations, we first normalized each sample to the internal standard. Serum samples of 10 μl were spiked with an internal standard then derivatized according to MassTrak instructions. The amino acid derivatizing reagent used was 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate. Then, concentrations based on the standard curve were determined. A 10-point standard concentration curve was made from the calibration standard solution to calculate amino acid concentrations in serum samples. High resolution separation was done using an Acquity UPLC system and injecting 1 ml of derviatized solution, with a UPLC BEH C18 column (Waters Corp, Milford, MA). Mass detection was completed on a TSQ Ultra Quantum running in ESI positive mode (Thermo Scientific, Waltham, MA).

Serum amino-acid calibration standards were prepared with MassTrak Amino Acid Analysis Solution (AAA) kit from Waters (Milford, MA, USA) according to instructions with slight modifications for detection on a mass spectrometer.^{33 (link)} A 10-point standard concentration curve was made from the calibration standard solution to calculate amino-acid concentrations in serum samples. Serum samples of 10 μl were spiked with an internal standard then derivatized according to MassTrak instructions. The amino-acid-derivatizing reagent used was 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate. High-resolution separation was done using an Acquity UPLC system and injecting 1 ml of derviatized solution, with a UPLC BEH C18 column (Milford, MA, USA). Mass detection was completed on a TSQ Ultra Quantum running in ESI-positive mode (Thermo Scientific, Waltham, MA, USA).