Determination for the Contents of Neu5Ac, Neu5Gc and KDN in Organ Meats and Muscle of Pigs by LC-MS/MS

目的：建立液相色谱-三重四级杆质谱联用法（LC-MS/MS）测定猪内脏和肌肉组织中唾液酸N-乙酰神经氨酸（Neu5Ac）、N-羟乙酰神经氨酸（Neu5Gc）和脱氨神经氨酸（KDN）浓度的分析方法。方法：将内脏肉组织匀浆后,利用三氟乙酸（TFA）将结合态的唾液酸从糖脂或糖蛋白链上解离下来后进样分析。色谱条件：色谱柱为ZORBAX Eclipse Plus C18（5μm,4.6×250 mm,Waters）,流动相为0.1%醋酸铵-100%乙腈（9：1）,柱温：25℃,流速800μL·min~（-1）,进样量20μL。质谱条件：离子源为电喷雾化离子源（ESI）,扫描方式为多重反应监测（MRM）,监测离子对：Neu5Ac：307.7→87.0,Neu5Gc：323.3→116.0,KDN：266.7→87.0,13C3Neu5Ac内标品：310.9→90.0。结果：Neu5Ac、Neu5Gc和KDN分别在0.1~20.0、0.05~10.00和0.005~1.000μmol·L~（-1）的浓度范围内和对照品与内标峰面积比值线性关系良好,重复性平均RSD为1.2%,稳定性平均RSD为1.9%,日间和日内精密度试验RSD均小于6.7%,平均回收率为92.9~106.4%。结论：本方法简便、快速、灵敏度高,可广泛运用于组织和体液中唾液酸的测定。Objective： To establish an LC-MS/MS method for the detection of N-acetylneuraminic acid（Neu5Ac）,N-glycolylneuraminic acid（Neu5Gc） and 2-keto-3-deoxy-D-glycero-D-galactonononic acid（KDN） in organ meats and muscle of pigs.Methods： Tissues were acid hydrolyzed with trifluoroacetic acid（TFA） to get ganglioside-bound and glycoprotein-bound sialic acid,followed by injected and analyzed. The analysis was performed on an ZORBAX Eclipse Plus C18（5 μm, 4.6 ×250 mm, Waters）column, and the mobile phase consisted of 0.1 % ammonium~-100 % acetonitrile（9：1）, the flow rate was 800 μL/min, the temperature was maintained at 25 ℃, injection volume was set up 20 μL. Negative electrospray ionization（ESI） and multiple reaction monitoring（MRM） mode was used, MRM： Neu5Ac： 307.7→87.0, Neu5Gc： 323.3 →116.0, KDN： 266.7→87.0, 13C3Neu5Ac（IS）： 310.9→90.0.Results： The ratio of internal with standard sample peak area and content of Neu5 Ac, Neu5 Gc and KDN showed good linearity in the range of 0.1~20.0, 0.05~10.00, and 0.005~1.000 μmol/L, RSDs of the repeatability and stability were 1.2 % and 1.9 %, Intra-and inter-day RSDs were all lower than 6.7%, the recoveries of sialic acid were 92.9~106.4%. Conclusion： The established method is simple,accurate and rapid, higher sensitivity and can be applied to determination of Neu5 Gc, Neu5 Ac and KDN in tissues and fluid of animals and human.国家自然科学基金项目（31271038

Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024

We present a measurement of the integrated luminosity e+e- of collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm = 3.773 GeV. The integrated luminosities of the datasets taken from December 2021 to June 2022, from November 2022 to June 2023, and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1, 8.157±0.031 fb-1, and 4.191±0.016 fb-1, respectively, by analyzing large angle Bhabha scattering events. The uncertainties are dominated by systematic effects, and the statistical uncertainties are negligible. Our results provide essential input for future analyses and precision measurements

Determination of the number of ψ(3686) events taken at BESIII

The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^