The invention discloses a high performance liquid chromatographic detection method for 3-cyanopyridine and 4-methylpyridine in 4-cyanopyridine. The high performance liquid chromatographic detection method comprises the following steps: (1) preparing a
system applicable solution; (2) preparing a
test solution; 3) preparing a contrast solution. The
system applicable solution, the
test solution and the contrast solution are detected respectively by adopting
high performance liquid chromatography. The detection condition is as follows: octadecylsilane chemically bonded silica is used as a filling agent of a
chromatographic column; a mobile phase A is modified buffer salt, and is prepared by adding 20 mmol of
potassium dihydrogen
phosphate and 2.4 ml of
triethylamine into 1000 ml of water and adjusting the pH value to 6.0-8.0 with
phosphoric acid; a mobile phase B is an organic phase, and adopts
gradient elution; the flow rate is 0.5-1.5 ml / min; the
column temperature is 10-40 DEG C; the detection wave length is 200-300 nm; the injected
sample volume is 10 [mu]l. The separation degree of 3-cyanopyridine, 4-cyanopyridine and 4-methylpyridine in the detection method are all 2.0 or above, the
theoretical plate number is high, the symmetry is good, and the condition that the accuracy of the detection results is influenced by interference between the components is effectively avoided; meanwhile, the detection method has the advantages of being accurate and reliable in detection result, short in analysis time, simple and convenient to operate, and the like.