Measurement of Sufentanil in Human Milk by Liquid Chromatography-Tandem Mass Spectrometry

A sensitive quantification method for sufentanil in human milk was developed. Samples were prepared by liquid-phase extraction. Analytes were chromatographically separated. The mobile phase contained 10 mM ammonium formate (A) and methanol (B). The ratios of A to B were 50:50, 10:90, and 50:50 sequentially. For LC-MS-MS detection, transition of the protonated precursor ions to product ions (sufentanil: m/z 387.2→m/z 238.2; internal control fentanil: m/z 337.2→m/z 158.2) was monitored. The linear quantification range of sufentanil concentration was 3.2–400 pg ·mL−1. The correlation coefficient (r2) was 0.996. The % RSD was less than 6.0% for intraday and less than 8.68% for interday precision. By this method, sufentanil contents were determined to be very low in the postnatal maternal milk samples.