Fig. 4From: High-throughput analysis of amino acids in plant materials by single quadrupole mass spectrometryAverage relative standard deviation of amino acid concentrations (n = 5) analyzed in increasing quantities of two different plant matrixes, viz. spinach (shaded columns) and a protein concentrate of ryegrass (black columns). Different letters indicate significant statistical difference based on ANOVA (p ≤ 0.05)Back to article page