The invention discloses a method for detecting 33 kinds of
narcotic drugs in
urine by liquid
chromatography-
tandem mass spectrometry, which is characterized by comprising the following steps: carrying out extraction and purification on samples by using a liquid-liquid extraction method, adding a
sodium hydroxide solution into the obtained object so as to realize albuminous degeneration and pH-value adjustment of the obtained object, and adding
ethyl acetate into the obtained mixture so as to carry out extraction on the obtained mixture through liquid-liquid extraction, then obtaining to-be-tested samples; carrying out determination on the to-be-tested samples by using a liquid
chromatography-tandem
quadrupole mass spectrometer, wherein, except for that barbiturates in the to-be-tested samples are analyzed in a negative
ion mode, the other compounds in the to-be-tested samples are analyzed in a positive
ion mode; and through taking the relative
retention time of each
narcotic drug and the abundance ratio of a monitoring
ion pair of each
narcotic drug as the qualitative basis, calculating the residual quantity of each narcotic
drug in the samples according to the
peak area or peak height of each narcotic drug. By using the method disclosed by the invention, 33 kinds of
narcotic drugs can be analyzed at one time, and the test cost is reduced, meanwhile, the method is strong in pertinence, simple in operation, fast in detection speed, wide in detection surface, and easy to popularize and apply. The method can be used in the quick detection and positive result confirmation of entry-exit inspection and
quarantine bureaus,
disease control centers and
public security departments.