Beagle犬脑脊液-血浆-粪便中短链脂肪酸分析

目的: 研究生理状态下Beagle犬脑脊液中的短链脂肪酸及与血浆-粪便中短链脂肪酸的关系。方法: 采用顶空气相色谱-质谱联用法快速分析Beagle犬脑脊液-血浆-粪便中的短链脂肪酸。Beagle犬脑脊液、血浆、粪便样本密封于顶空进样瓶中,直接用于HS-GC/MS检测。加热炉温度80 ℃,顶空进样环温度100 ℃,传输管温度150 ℃,振荡加热时间20 min,顶空进样1 mL;采用DB-FFAP毛细管柱(30 m×0.25 mm×0.25 μm),进样口温度250 ℃,升温程序(初始温度50 ℃保持1 min,以10 ℃·min^-1升至200 ℃),载气(高纯氦)流速1.0 mL·min^-1;电子轰击(electron impact,EI)离子源,电子能量-70 eV,离子源温度250 ℃,接口温度250 ℃,电子倍增器电压0.91 kV,全扫描模式,扫描范围m/z 33~200。结果: 通过对照品比对和NIST标准谱库检索,在Beagle犬脑脊液中鉴定了乙酸、丙酸、异丁酸、丁酸、异戊酸、戊酸、己酸7个短链脂肪酸,经面积归一化乙酸占90.12%±2.79%;血浆中检测到7个相同的短链脂肪酸,经面积归一化乙酸占85.01%±3.28%;粪便中鉴定了8个短链脂肪酸:乙酸、丙酸、异丁酸、丁酸、异戊酸、戊酸、异己酸、己酸,经面积归一化乙酸占41.57%±5.08%。结论: 脑脊液中短链脂肪酸的种类和比例与血浆中的基本一致,均以乙酸为主;粪便中的短链脂肪酸以乙、丙、丁酸为主。顶空气相色谱-质谱联用法可用于Beagle犬脑脊液-血浆-粪便中短链脂肪酸的快速检测。

Objective: To study the relationship of short-chain fatty acid(SCFA)in cerebrospinal fluids and SCFA in plasma and feces from Beagles in physiological state. Methods: Headspace gas chromatography tandem mass spectrometry(HS-GC/MS)was used for this study.Cerebrospinal fluids,plasma and feces were sealed in the headspace bottle for direct HS-GC/MS analysis.The HS-GC/MS method was optimized as follows: the oven temperature(temp.)at 80 ℃,the manifold temp.at 100 ℃,the tube temp.at 150 ℃,the incubation time of 20 min,the injection volume of 1 mL.The chromatographic separation was performed on a DB-FFAP capillary column(30 m×0.25 mm×0.25 μm)with the injection port temp.at 250 ℃.The temperature program(the initial temp.at 50 ℃ within the first 1 min,and raised to 200 ℃ by 10 ℃·min^-1)was employed by fixing the flow rate of carrier gas(high purity helium)at 1.0 mL·min^-1.The electron energy at-70 eV was set for electron impact(EI)ionization,with the ion source temp.at 250 ℃,the interface temp.at 250 ℃,the voltage of electron multiplier at 0.91 kV.The spectra were recorded in the range of m/z 33-200 for full scan. Results: By comparing with the standards and retrieving the NIST library,seven SCFAs were identified in the cerebrospinal fluids and plasma from Beagles,and the relative percentage contents of acetic acid accounted for 90.12%±2.79% in cerebrospinal fluids and 85.01%±3.28% in plasma of all SCFAs by area normalization,respectively.Besides,eight SCFAs were detected in feces.By area normalization,the relative percentage contents of acetic acid in feces accounted for 41.57%±5.08% of all SCFAs. Conclusion: The type and the proportion of SCFAs in cerebrospinal fluids were basically identical with those in plasma and the main type was acetic acid. In feces,acetic,propionic and butyric acids were the highest.The HS-GC/MS method could be used to rapidly analyze SCFA in cerebrospinal fluids,plasma and feces from Beagles.