To determination of sufentanil in human breast milk during the administration of the sufentanil via the analgesic infusion pump and after the administration, to determine whether the breastfeeding after clinical anesthetic or analgesic administration has an effect on the infant and provide a reference for the security issues.

The concentration of sufentanil in milk was determined by LC-MS /MS method( liquid chromatography mass spectrometry).The separation was carried on Agilent ZORBAX Eclipse Plus C18 column(2.1×50 mm, 3.5 μm)with a mobile phase of 10 mmol ammonium formate(A)and methanol(B), and the elution conditions were optimized as follows：linear gradient 0→0.30 min, A:B=50:50; 0.30→0.31 min, A:B=50:50→10:90; 3.00→3.10 min, A:B=10:90→50:50; 3.1→6.5min, A:B=50:50; The flowing rate was 0.2 mL•min-1, column temperature was 30 ℃, injection volume was 5 μL. ESI source was applied and operated in positive ion mode. Quantitative determination was performed using multiple reaction monitoring (MRM) of m/z 387.2 → m/z 238.2 for sufentanil, and m/z 337.2 → m/z 158.2 for fentanyl.

Inclusion Criteria:

• Aged 20yr to 38yr
• Height 155~170 cm
• Weight 65~85 Kg
• American Society of Anesthesiologists statuses I or II
• Normal cardiac and pulmonary function
• Undergoing elective Cesarean section
• Willing to provide breast milk

Exclusion Criteria:

• pregnancy induced hypertension
• gestational diabetes
• gestational heart disease