EASC荧光标记和LC-APCI-MS检测环境水样中游离脂肪胺

采用新型荧光标记试剂10-乙基吖啶酮-2-磺酰氯(EASC)作为柱前衍生试剂, 在Hypersil BDS C18反相色谱柱上(4.6 mm×200 mm, 10 μm i.d.), 采用梯度洗脱在20 min内实现了12种EASC-脂肪胺衍生物的快速基线分离. 最佳检测波长为λex/λem=270 nm/430 nm. EASC与常用的Dansyl-Cl相比具有更强的光致发光特性(紫外和荧光): 紫外吸收强度之比为3.2∶1, 相对荧光强度之比为30.0∶1~105.4∶1, 荧光量子效率之比为43.0∶1. 通过荧光检测及离子阱大气压化学电离源的正离子模式获得了胺类组分的准确定量和相应的柱后质谱鉴定. 质谱灵敏度之比为1.6∶1~6.2∶1. 建立的方法对环境水样中脂肪胺类化合物的测定具有快速、准确和重现性良好等优点, 回归系数大于0.9995, 检出限为4.0~12.7 fmol.

Determination of Free Aliphatic Amines in Environmental Water by EASC Derivatization and Identification with LC-APCI-MS

On a reversed-phase Hypersil BDS C18(4.6 mm×200 mm, 10 μm i.d.) column, 12 aliphatic amines were derivatized using 10-ethyl-9-oxo-9,10-dihydroacridine-2-sulfonyl chloride(EASC) as a new pre-column derivatization reagent. The complete baseline resolution was obtained in conjunction with a gradient elution with acetonitrile/H2O as mobile phase within 20 min. The optimum excitation and emission wavelengths were at λex/λem=270 nm/430 nm. Comparing with the widely used Dansyl-Cl, EASC has stronger photoluminescence characteristics(ultraviolet and fluorescence): UVEASC/UVDansyl-Cl=3.2(UV: ultraviolet absorption intensity); I(EASC)/I(Dansyl-Cl)=30.0∶1—105.4∶1(I: relative fluorescence intensity); fluorescence quantum yield: Φf(EASC)/Φf(Dansyl-Cl)=43.0∶1. Fast and accurate quantitative analysis of aliphatic amines with fluorescence and corresponding post-column ion trap mass spectrometry(LC-APCI-MS) were obtained. EASC-amines exhibited stronger mass spectrometric sensitivity relative to that of dansyl-amine derivatives: MSEASC/MSDansyl-Cl=1.6∶1—6.2∶1 times(MS: relative intensity of ion current). The established method for the determination of aliphatic amines in environmental water samples exhibited good reproducibility and recovery. Excellent linear responses were observed with the correlation coefficients >0.9995. The detection limits(at signal-to-noise of 3∶1) were at levels of 4.0—12.7 fmol.