衍生化-顶空固相微萃取-气相色谱法测定大鼠粪便中游离短链脂肪酸

为满足生物样品中短链脂肪酸的痕量检测需求,以氯甲酸丙酯为衍生试剂,结合顶空固相微萃取,建立了基质内衍生 顶空固相微萃取 气相色谱方法用于大鼠粪便中7种游离短链脂肪酸的测定。在最佳衍生条件（pH8、300 μL丙醇、100 μL吡啶、100 μL氯甲酸丙酯及涡旋衍生2 min）及顶空固相微萃取的条件（pH3.46、萃取温度50℃、萃取时间40 min和转速1 000 r/min）下,该方法的检出限在0.133~0.420 μmol/kg,定量限在0.444~1.400 μmol/kg,远低于其他文献中所建方法的检出限和定量限,而且线性关系好(R2>0.99),精密度和准确度高,加标回收率在65.42%~117.69%,相对标准偏差低于11.60%。该方法操作简单、快速、灵敏且廉价,完全能够满足粪便中短链脂肪酸痕量检测需求     

Quantification of long‐chain fatty acids in dissolved organic matter and soils

The objective was to develop and adapt a versatile analytical method for the quantification of solvent extractable, saturated long‐chain fatty acids in aquatic and terrestrial environments. Fulvic (FA) and humic (HA) acids, dissolved organic matter (DOM) in water, as well as organic matter in whole soils (SOM) of different horizons were investigated. The proposed methodology comprised extraction by dichloromethane/acetone and derivatization with tetramethylammonium hydroxide (TMAH) followed by gas chromatography/mass spectrometry (GC/MS) and library searches. The C_10:0 to C_34:0 methyl esters of n‐alkyl fatty acids were used as external standards for calibration. The total concentrations of C_14:0 to C_28:0 n‐alkyl fatty acids were determined in DOM obtained by reverse‐osmosis of Suwannee river water (309.3 μg g^—1), in freeze‐dried brown lake water (180.6 μg g^—1), its DOM concentrate (93.0 μg g^—1), humic acid (43.1 μg g^—1), and fulvic acid (42.5 μg g^—1). The concentrations of the methylated fatty acids (n‐C_16:0 to n‐C_28:0) were significantly (r² = 0.9999) correlated with the proportions of marker signals (% total ion intensity (TII), m/z 256 to m/z 508) in the corresponding pyrolysis‐field ionization (FI) mass spectra. The concentrations of terrestrial C_10:0 to C_34:0 n‐alkyl fatty acids from four soil samples ranged from 0.02 μg g^—1 to 11 μg g^—1. The total concentrations of the extractable fatty acids were quantified from a Podzol Bh horizon (26.2 μg g^—1), Phaeozem Ap unfertilized (48.1 μg g^—1), Phaeozem Ap fertilized (57.7 μg g^—1), and Gleysol Ap (66.7 μg g^—1). Our results demonstrate that the method is well suited to investigate the role of long‐chain fatty acids in humic fractions, whole soils and their particle‐size fractions and can be serve for the differentiation of plant growth and soil management.     

液相色谱法检测磺胺类药物柱后衍生反应条件优化

采用液相色谱柱后衍生法检测磺胺类药物,衍生化反应效果对检测结果有较大影响.通过正交实验,对影响衍生化反应的主要因素进行优化,得出磺胺在线柱后衍生优化条件为:流动相pH值3.0、反应温度60℃、流动相乙腈比例18％、衍生化试剂荧光胺浓度0.25mg/mL.     

氨基酸分析中的柱前衍生技术

介绍了以邻苯二甲醛、氯甲酸芴甲酯、异硫氰酸苯酯、丹酰氯、二甲胺偶氮苯磺酰氯和6-氨基喹啉-N-羟基琥珀酰亚胺基氨基甲酸酯等作为衍生试剂的柱前衍生与反相高效液相色谱法相结合分析氨基酸的原理及特点。