血清中游离脂肪酸的液相色谱荧光测定及质谱鉴定

利用新型荧光试剂1,2 苯并 3,4 二氢咔唑 9 乙基对甲苯磺酸酯(BDETS)对19种游离脂肪酸(FFAs)进行柱前衍生,在EclipseXDB C8反相色谱柱上,采用梯度洗脱优化分离.90℃下在DMF溶剂中以K2CO3作催化剂,衍生反应30min获得稳定的荧光产物.激发和发射波长分别为λex=333nm,λem=390nm,采用大气压化学电离源(APCI)正离子模式进行柱后在线质谱定性.多数脂肪酸的线性回归系数大于0.9989,检测限为24.80～80.37fmol.实现了人体血清中长链脂肪酸的定性及相应含量测定.     

大果白刺游离脂肪酸的柱前衍生高效液相色谱-荧光检测法分析

采用2-（11H-苯[a]咔唑）乙基对甲苯磺酸酯（BCETS）为柱前荧光衍生试剂,通过梯度洗脱使得18种脂肪酸在BDS-C8柱上得到良好的分离.方法应用于大果白刺不同部位中游离脂肪酸的分析,结果表明大果白刺的果皮果肉和叶子中均含有大量的不饱和脂肪酸,其总不饱和脂肪酸含量分别为70.74%和73.47%.大果白刺种子中不饱和脂肪酸的含量相对较少,仅占总脂肪酸含量的57.21%,其不饱和脂肪酸组成主要是C18∶1（油酸）和C18∶2（亚油酸）.其中,大果白刺的果皮果肉中,不饱和脂肪酸主要是C18∶1、C18∶2和C18∶3（亚麻酸）.其叶子中的不饱和脂肪酸主要是C18∶3,所占总脂肪酸比例为48.34%.首次对大果白刺中的脂肪酸进行了分析,可以为大果白刺在食品、药品中的进一步开发应用和质量控制提供一定的数据支持.     

鼠类粪便中类固醇的荧光标记及质谱鉴定

利用新型荧光试剂1,2-苯并-3,4-二氢咔唑-9-乙基肼基甲酸酯(BCEC)作柱前衍生化试剂,在HypersilBDSC18(4.6mm×200mm,5μm)色谱柱上,采用梯度洗脱对皮质醇、皮质酮、睾酮、孕酮4种类固醇荧光衍生物进行了优化分离。65℃下在乙腈溶剂中以三氯乙酸作催化剂,衍生反应2h后获得稳定的荧光产物。激发和发射波长分别为333nm和390nm。采用大气压化学电离源(APCI)正离子模式,实现了黑线姬鼠粪便中4种类固醇化合物的定性及定量测定。线性回归系数均在0.9999以上,检出限为47.3~71.2fmol。     

氮杂多环光致发光分子用于食品中脂肪胺的分析及质谱鉴定

对含氮类光致发光分子2-（11H-苯[a]咔唑）-异丙基氯甲酸酯进行柱前衍生处理,并经荧光检测对脂肪胺进行高效液相色谱（HPLC）分离和质谱定性。衍生物于λex=279nm产生强烈荧光,发射波长为λex=380nm。40℃下在pH9．0的硼酸缓冲液中,衍生反应3min后获得稳定的荧光产物。在Eclipse XDB-C8色谱柱（4．6mm×150mm,5μm）上,采用梯度洗脱对12种脂肪胺衍生物进行了优化分离。采用大气压化学电离源（APCI Source）正离子模式进行质谱定性,实现了各种脂肪胺衍生物的快速、准确测定。该方法具有良好的重复性,多数脂肪胺的线性回归系数大于0．9994,检出限在2．73～23．16fmol水平。     

HPLC-APCI-MS法分析测定白刺籽油中游离脂肪酸

利用荧光衍生试剂1,2-苯并-3,4-二氢咔唑-9-乙基对甲苯磺酸酯(BDETS)作为脂肪酸柱前衍生化试剂,采用梯度洗脱在Eclipse XDB-C8色谱柱上对游离脂肪酸(FFA)(油酸、亚油酸、软脂酸和硬脂酸)衍生物进行分离.利用柱后在线的串联质谱以大气压化学电离源(APCI)正离子模式实现了各组分的质谱定性.荧光检测的激发和发射波长分别为λex=333 nm,λem=390 nm.脂肪酸的线性回归系数大于0.9990,检出限为3.38～6.59 nmol/L.建立的方法具有良好的重现性.利用此方法对超临界CO2提取的唐古特白刺籽油中几种游离脂肪酸进行了分析.结果表明白刺籽油中含有大量的游离不饱和脂肪酸.     

高效液相色谱荧光测定及质谱鉴定分析血清中胆汁酸

利用新型荧光试剂1,2-苯并-3,4-二氢咔唑-9-乙基苯磺酸酯(BDEBS)作柱前衍生化试剂,在EclipseXDB-C8色谱柱上,采用梯度洗脱对10种胆汁酸(BAs)荧光衍生物进行了优化分离。95℃下在二甲基亚砜(DMSO)溶剂中以柠檬酸钾作催化剂,衍生反应35min后获得稳定的荧光产物,衍生反应完全。荧光激发和发射波长分别为λex=333nm,λem=390nm。采用大气压化学电离源(APCISource)正离子模式,实现了血清中胆汁酸的定性测定。分析物的定量测定采用荧光法进行。线性回归系数均在0.9996以上,检出限为22.36~44.57×10-15mol。     

反相高效液相色谱法测定鼠胆汁中游离与结合型胆汁酸

建立了一种柱前衍生反相高效液相色谱荧光检测大鼠胆汁中游离与结合型胆汁酸的方法.以4-溴甲基-7-甲氧基香豆素为衍生剂,月桂酸为內标,Waters Nova C18色谱柱分离,采用甲醇/乙腈和水梯度洗脱,荧光激发波长(λex)330 nm,发射波长(λem)400 nm,內标标准曲线法定量.各胆汁酸在5-2 400μmol/L范围内线性良好,r为0.998 9-0.999 7.最低检出限为1.2-2.5μmol/L.精密度日内在1.05%-3.67%之间,日间在3.16%-6.83%之间.平均回收率为87.8%-106.7%.该方法灵敏、重复性好,分析时间短,线性范围宽,适合于科研工作中对鼠胆汁中各胆汁酸进行定量检测.     

污水中脂肪胺荧光衍生物的高效液相色谱分离及质谱鉴定

利用新型荧光试剂1,2-苯并-3,4-二氢咔唑-9-异丙基氯甲酸酯(BCIC)作为柱前衍生化试剂,在乙腈中,以硼酸钠缓冲液(pH 9)为催化剂,40 ℃下衍生反应10 min后获得稳定的荧光产物.在Eclipse XDB-C8色谱柱上,通过梯度洗脱对12种游离脂肪胺进行了分离和在线质谱定性.激发和发射波长分别为λex=333 nm,λem=390 nm.采用大气压化学电离源(APCI)正离子模式,实现了污水中脂肪胺的定性及相应含量测定.脂肪胺的线性回归系数大于0.9996,检出限在10.57～37.83 fmol.     

新型荧光衍生试剂用于脂肪胺的反相高效液相色谱-荧光检测分析

利用新型荧光试剂4-(1H-菲并[9,10-d]咪唑-2-)苯甲酸(PIBA)进行柱前衍生并经荧光检测对脂肪胺进行了高效液相色谱(HPLC)分离和在线质谱定性。激发和发射波长分别为ex=261nm,em=443nm。80℃下在吡啶溶剂中用N-乙基-N’-[(3-二甲氨基)丙基]碳二亚胺盐酸盐(EDC)做催化剂,衍生反应10min后获得稳定的荧光产物。在EclipseXDB-C8色谱柱(4.6150mm,5mm)上,梯度洗脱对12种游离脂肪胺衍生物进行了优化分离。采用大气压化学电离源(APCI)正离子模式,实现了各种脂肪胺衍生物的测定。多数脂肪胺的线性回归系数大于0.9999,检测限为10.5～53.4fmol。     

A new fluorescent derivatization reagent and its application to free fatty acid analysis in pomegranate samples using HPLC with fluorescence detection

A new fluorescent labeling reagent has been developed for the determination of fatty acids (FAs) by HPLC with fluorescence detection. The derivatization conditions including the amount of derivatization reagent, temperature, and type of catalyst were investigated, the results indicated that the reaction proceeded within 30 min at 90°C in the presence of K₂CO₃ catalyst. The maximal yield was obtained with a four‐ to fivefold molar reagent excess. The derivatives exhibited strong fluorescence with an excitation maximum at λ_ex = 245 nm and an emission maximum at λ_em = 410 nm. Twenty‐five FA derivatives were well separated by RP‐HPLC on a Hypersil BDS C₈ column in combination with gradient elution. All FAs were found to give excellent linear responses with correlation coefficients >0.9992. The method gave a low LOQ of 0.85–5.5 ng/mL (S/N of 10). The developed method was employed to analyze free FAs (FFAs) composition in pomegranate samples without any purification. FFAs in samples were doubly identified by HPLC retention time and protonated molecular ion corresponding to m/z [M+H]⁺. This newly developed method allows a highly sensitive determination of trace FFAs from pomegranate and other foodstuffs.     

多级溶剂萃取-气相色谱法测定啤酒中的游离脂肪酸

啤酒中含量极低、极不稳定的游离脂肪酸是影响啤酒风味重要因素之一。本文采用溶剂萃取和气相色谱联用技术,对啤酒不良风味物质游离脂肪酸进行了检测。啤酒样品经3次萃取(有机溶剂萃取、碱液反萃取、有机溶剂萃取)后,通过甲醇-硫酸甲酯化处理,最后用正己烷萃取浓缩进行气相色谱(GC)分析。该方法中以辛酸、癸酸和月桂酸为代表的平均回收率分别为86.26%、92.19%和83.57%。辛酸、癸酸、月桂酸、棕榈酸在2.326~2326 mg/L,0.362~362 mg/L,0.250~250 mg/L,0.330~330 mg/L范围内线性良好,相关系数在0.9996~0.9999之间。     

Separation of triacylglycerols and free fatty acids in microalgal lipids by solid-phase extraction for separate fatty acid profiling analysis by gas chromatography

Microalgal lipids were separated into two fractions, triacylglycerols (TAGs) and free fatty acids (FFAs), by solid-phase extraction employing sodium carbonate as the sorbent and dichloromethane (20% by volume) in n-hexane as the extracting solvent. The TAG fraction was then saponified, followed by acidification, extraction and tert-butyldimethylsilyl esterification. The FFA fraction was directly acidified, extracted and derivatized. From the lipid extracts of eight microalgal species examined, a total of 13 fatty acids were detected in the TAG fractions and nine were found in the FFA fractions, with at much higher total TAG content in all microalgae. Oleic acid was the most prominent fatty acid in three species, α-linolenic acid was more abundant in two others, and palmitic acid was present in highest concentration in the remaining three species.     

Identification of fatty acid methyl esters as minor components of fish oil by multidimensional GC-MSD: New furan fatty acids

The separation and analysis of furan fatty acids and other minor component fatty acids present at very low concentrations in complex sample matrices, such as fish oil or lipids derived from liver and testes, require several pre-analytical separation steps if single column gas chromatography is to furnish sufficient resolution: after extraction and transesterification hydrogenation, urea complex precipitation and argentation TLC have been applied prior to GC analysis of furan fatty acids. By using multidimensional GC-MSD with cooled injection and flow-controlled column switching with intermediate cold trapping, it has been possible to identify directly the methyl esters of furan fatty acids without further pre-analytical separation. The most common of the furan fatty acids can be subdivided into two groups depending on whether they bear a propyl or pentyl side group in the 5-position of the furan ring. In addition to the eight furan fatty acids known to be present in fish oil, six new ones were identified, four with propyl substitution and two with pentyl substitution. Four have earlier been reported to be present in the hepatopancreas of crayfish and in fish tissue, whereas the propyl-substituted 16,19-epoxy-17,18-dimethyldocosa-16,18-dienoic acid and the pentyl-substituted furan fatty acid 6,9-epoxy-7-methyltetradeca-6,8-dienoic acid were hitherto unknown.     

尿素包合法分离蚕蛹油中多不饱和脂肪酸

蚕蛹是缫丝副产品,我国每年副产近20万吨干蛹[1].蚕蛹中油脂含量相当丰富,约占蚕蛹干基的25%～29%,且油脂总量的71.0%为不饱和脂肪酸,这些不饱和脂肪酸在人体内可合成二十碳五烯酸及二十二碳六烯酸,与鱼油中的EPA,DHA具有相似的抗衰老、健脑益智的功能,能维持正常的肾脏功能,治腰背疼痛、肌肉无力,预防动脉硬化、血脂升高等血栓疾病[2].     

Determination of free amino acids by precolumn derivatization with phenylisothiocyanate. Application to wine samples

Summary A method to determine free amino acids by pre-column derivatization with phenylisothiocyanate is discussed. The method has been applied to determine free amino acids in wine samples, and the results have been compared with those obtained by means of an automatic orthophthal-aldehyde-9-fluorenylmethyloroformate (OPA-FMOC) method.     

Mass spectrometric analysis of free fatty acids in infant milk powders by frozen pretreatment coupled with isotope‐labeling derivatization

In combination with frozen pretreatment and carboxyl group derivatization, a novel workflow was developed for the determination of free fatty acids in milk powder. The workflow showed a significantly enhanced performance for comprehensive free fatty acid analysis owing to a highly efficient frozen extraction method. In addition, the advantages of the workflow also involved high sensitivity and great tolerance to a complex matrix. Characteristic fragment ions of derivatization reagents also provide clear evidence for the qualitative analysis of free fatty acids. Fourteen types of free fatty acids in a number of domestic and overseas infant milk powders have been successfully detected. The content of free fatty acids in the different samples was different, which probably indicates the diverse quality of infant milk powder. The workflow is expected to be a pragmatic tool for the analysis of free fatty acids in intricate matrices.     

Direct, reagent-free determination of free fatty acid content in olive oil and olives by Fourier transform Raman spectrometry

Fourier transform (FT) Raman spectrometry in combination with partial least squares (PLS) regression was used for direct, reagent-free determination of free fatty acid (FFA) content in olive oils and olives. Oils were directly investigated in a simple flow cell. Milled olives were measured in a dedicated sample cup, which was rotated eccentrically to the horizontal laser beam during spectrum acquisition in order to compensate sample heterogeneity. Both external and internal (leave-one-out) validation were used to assess the predictive ability of the PLS calibration models for FFA content (in terms of oleic acid) in oil and olives in the range 0.20-6.14 and 0.15-3.79%, respectively. The root mean square error of prediction (RMSEP) was 0.29% for oil and 0.28% for olives. The predicted FFA contents were used to classify oils and olives in different categories according to the European Union regulations. Ninety percent of the oil samples and 80% of the olives were correctly classified. These results demonstrate that the proposed procedures can be used for screening of good quality olives before processing, as well as, for the on-line control of the produced oil.     

Determination of free fatty acids by capillary zone electrophoresis

Capillary zone electrophoresis was investigated for the separation of free fatty acids as an alternative to well established techniques such as GC or HPLC. The analysis was performed with indirect UV detection in a counterelectroosmotic flow mode using a diethylbarbiturate carrier electrolyte at a pH between 10 and 11 in a mixed aqueous-organic solvent. Separation of saturated and unsaturated fatty acids could be achieved after bromination of the double bonds. Problems with wall adsorption of fatty acids could be overcome by increasing the temperature and using a high concentration of a zwitterionic reagent to inactivate the silica surface. Increased sensitivity could be achieved after preconcentration on alumina. The method was applied to the determination of free fatty acids in dairy products. The advantages compared to traditional methods include short analysis times and simple preparation steps.Dedicated to Univ. Prof. Dr. Karl Winsauer on the occasion of his 70th birthday