An efficient method for the analysis of cefotaxime and its metabolite desacetylcefotaxime residues in eggs was developed based on high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).The samples were homogenized and extracted with acetonitrile/water (9∶1, V/V) solution.The fat was removed by hexane, and the other impurities were removed with C18 sorbent.The separation of cefotaxime and desacetylcefotaxime was performed on an Agilent Eclipse Plus C18 column (100 mm × 2.1 mm, 3.5 μm) using a mobile phase of 0.2% formic acid(A)-acetonitrile(B) by gradient elution.The analytes were detected by MS/MS in positive electrospray ionization mode (ESI+) and multiple reaction monitoring (MRM), quantitated by matrix-matched extemal standard method.Results showed that the calibration curves had a good linearity in the range of 1.0-143 μg/L (cefotaxime) and 1.0-120 μg/L (desacetylcefotaxime), respectively, with correlation coefficient R.2>0.999.Limits of detection (LOD, S/N=3) for cefotaxime and desacetylcefotaxime were 0.07 and 0.14 μg/kg, and limits of quantitation (LOQ, S/N=10) for cefotaxime and desacetylcefotaxime were 0.23 and 0.99 μg/kg, respectively.At three spiked concentration levels, the recoveries of cefotaxime and desacetylcefotaxime ranged from 83.1% to 103.0% and 88.2% to 101.0%, respectively, both with RSDs (n=6) less than 6.2%.The results demonstrated that the method was simple, quick, sensitive and reliable, and suitable for determination of cefotaxime and desacetylcefotaxime residues in eggs.

Objective To investigate the causes and countermeasures of reoperation following laparoscopic pancreatoduodenectomy.Methods The causes,approaches and outcome of reoperation were retrospectively analyzed in 10(4.0％,10/250) patients undergoing reoperations following pancreaticoduodenectomy with various complications in Hunan Provincial People's Hospital from April 2014 to April 2018.Results The causes of the 10 patients including intra-abdominal bleeding of seven cases (2 cases combined with pancreatic fistula,1 case with pancreatic and biliary fistula),1 patient with gastrointestinal anastomosis output perforation,1 patient with intra-abdominal abscess,and 1 case with postoperative pancreatitis.The time of reoperation was one day to 82 day after the first operation.The main methods of reoperation including suture and hemostasis,rebuilding the digestive tract,gastrostomy and enterostomy combined with abdominal cavity drainage.The mortality of reoperation following laparoscopic pancreatoduodenectomy was 20.0％ (2/10).Conclusions Intra-abdominal hemorrhage,pancreatic fistula and intra-abdominal abscess are the major causes of reoperation after laparoscopic pancreatoduodenectomy.Timely and decisive reoperation is an effective means to reduce postoperative morbidity and mortality after LPD.