Detection method of substances relative to raw material and preparation of ambrisentan

The invention provides a detection method of relative substances in raw materials and preparations of ambrisentan. The method is carried out through an HPLC method and includes following steps: (1) preparing a sample solution of the ambrisentan; and (2) feeding the sample solution into an HPLC instrument, performing gradient elution to the sample solution with a mobile phase A and a mobile phase B as a mobile phase and recording a chromatogram, wherein a stationary phase filling agent of a chromatographic column of the HPLC is octadecylsilane chemically bonded silica or octylsilane chemically bonded silica; the mobile phase A is prepared from acetonitrile and a phosphate buffer solution with a volume ratio being 30-50:50-70; and the mobile phase B is prepared from acetonitrile and a phosphate buffer solution with a volume ratio being 50-80:20-50. By means of the detection method, under the same liquid-phase condition, the relative substances in the raw materials or the preparations of the ambrisentan can be measured. The detection method is simple in operation, is high in separation degree, is strong in specificity and is accuracy and reliable in result.