Quantitative measurement of blood remifentanil concentration: development of a new method and clinical application

We have developed a new detection method of blood remifentanil concentration using a gas chromatography-mass spectrometry(GC–MS) with fentanyl as the internal standard(IS). The detection was performed at m / z 168 and 245 for remifentanil and fentanyl, respectively. In addition, the retention times of remifentanil and fentanyl were 5 min 45 s and 6 min 51 s, respectively. The standard curve of relationship between remifentanil concentration and the ratio of the peak area of remifentanil to fentanyl was satisfactorily fitted as linear regression ( R 2 = 0.998, p