液相色谱-串联质谱法测定海参和海胆中的单唾液酸神经节苷脂

建立了液相色谱-四极杆串联质谱法定量检测海参和海胆中单唾液酸神经节苷脂的分析方法。采用Svennerholm法从海胆或海参样品中提取神经节苷脂,经C8固相萃取柱净化,采用APS-2 NH₂柱(150 mm×2.1 mm, 3 μm),以乙腈和50 mmol/L乙酸铵溶液(pH 5.6)为流动相,梯度洗脱。样品中每种成分的定量在多反应监测模式下进行。该方法具有极高的灵敏度,定量限可低至纳克级。非硫酸酯化单唾液酸神经节苷脂(NMG)和硫酸酯化单唾液酸神经节苷脂(SMG)在1～40 ng进样量范围内呈现良好的线性关系;定量结果显示所测海参样品中美国红参的NMG含量最高,海胆样品中紫海胆的SMG含量最高;海胆中总的单唾液酸神经节苷脂含量(4.30～6.40 mg/g)明显高于各海参样品(8～131 μg/g)。该方法稳定可靠,适合海胆和海参中微量单唾液酸神经节苷脂的定量分析。

Determination of monosialogangliosides in sea cucumbers and sea urchins using liquid chromatography-tandem mass spectrometry

An approach based on liquid chromatography-tandem mass spectrometry was developed for the quantification of monosialogangliosides (MG) in sea cucumbers and sea urchins. The gangliosides of sea cucumbers and sea urchins were extracted according to the Svennerholm method and cleaned up by C8 solid phase extraction column. The extracts were separated on an APS-2 NH₂ column (150 mm×2.1 mm, 3 μm) with the mobile phases of acetonitrile and 50 mmol/L ammonium acetate (pH 5.6) under gradient elution. Multiple reaction monitoring(MRM) was performed for quantification of each analyte in the samples. The method was capable to distinguish gangliosides with different types of sialic acid in a single run. The limit of quantification was 0.22 ng for nonsulfated monosialoganglioside (NMG) and 0.29 ng for sulfated monosialoganglioside (SMG), and the linear range was 1-40 ng for both compounds. Only NMG was detected in sea cucumbers while both NMG and SMG were detected in sea urchins. Quantification results suggested that NMG was most abundant in Parastichopus californicus among all the sea cucumbers detected and SMG was most abundant in Anthocidaris crassispina among all the sea urchins. The contents of MGs in sea urchins (4.30-6.40 mg/g) were much higher than those in sea cucumbers (8-131 μg/g). The method is suitable for the quantification of monosialogangliosides in sea urchins and sea cucumbers.