“…Today, many methods such as high performance liquid chromatography (HPLC) [9,10], fluorescent detector HPLC [11], liquid chromatography-tandem mass spectrometry [12], spectrophotometry [13], spectrofluorimetry [14], amperometry [15], capillary electrophoresis technique [16], colorimetric method [17] and infrared optical sensor [18] are used to determine the amount of tryptophan. Although these methods are very important for quantitative analysis, most of them have disadvantages such as high costs, complex analysis process, long analysis time, long optimisation conditions and variables that depend on the analyst's ability.…”