Sendra J M, Navarro J L, Izquierdo L
Instituto de Agroquimica y Tecnologia de Alimentos (CSIC), Valencia, Spain.
J Chromatogr Sci. 1988 Sep;26(9):443-8. doi: 10.1093/chromsci/26.9.443.
A new analytical methodology for the determination of fully methoxylated flavones (FMFs) in citrus juices is described. Isolation of the FMFs is carried out by percolation of 30 mL of clarified citrus juice (to which tetramethyl-o-kaempferol is previously added as internal standard) through a C18 Sep-Pak cartridge, washing with 3 mL of water followed by 5 mL of water/acetonitrile (3:1), and selective elution of the retained FMFs with 5 mL of water/acetonitrile (9:11). Determination of the isolated FMFs is carried out by reversed-phase high-performance liquid chromatography (HPLC) and UV diode array detection (DAD). Signals at wavelengths 320, 335, and 345 nm (bandwidth 4 nm) are simultaneously acquired, stored, plotted, and integrated. The column used is a microbore (200 x 2.1-mm) Hypersil ODS 5 microns. Elution is in gradient mode, using a ternary mobile phase (water/acetonitrile/tetrahydrofuran). Column temperature is 40 degrees C. Recovery yields are nearly 100% for all the FMFs detected and identified: isosinensetin, hexamethyl-o-gossypetin, sinensetin, tetramethyl-o-isoscutellarein, hexamethyl-o-quercetagetin, nobiletin, tetramethyl-o-scutellarein, heptamethoxyflavone, and tangeretin. Chromatographic separation of the FMFs is extremely dependent upon the minor changes of the mobile phase composition and percentages, gradient rate, and temperature. The UV spectra (230 to 400 nm) of the FMFs obtained under chromatographic conditions are given. The FMFs relative response factors at 320, 335, and 345 nm and their concentrations in hand-squeezed and commercial concentrated orange and mandarin juices are tabulated. The FMF concentration differences found among samples are discussed.
本文描述了一种用于测定柑橘汁中全甲氧基黄酮（FMF）的新分析方法。通过将30 mL澄清柑橘汁（预先添加四甲基 - o - 山奈酚作为内标）通过C18 Sep - Pak柱进行渗滤来分离FMF，先用3 mL水洗，再用5 mL水/乙腈（3:1）洗，然后用5 mL水/乙腈（9:11）选择性洗脱保留的FMF。通过反相高效液相色谱（HPLC）和紫外二极管阵列检测（DAD）对分离出的FMF进行测定。同时采集、存储、绘制和积分320、335和345 nm波长（带宽4 nm）处的信号。使用的色谱柱是200×2.1 mm、5微米的Hypersil ODS微径柱。采用梯度洗脱模式，使用三元流动相（水/乙腈/四氢呋喃）。柱温为40℃。所有检测和鉴定出的FMF（异川陈皮素、六甲氧基棉黄素、川陈皮素、四甲基 - o - 异黄芩素、六甲氧基 - o - 槲皮万寿菊素、诺米林、四甲基 - o - 黄芩素、七甲氧基黄酮和橘红素）的回收率接近100%。FMF的色谱分离极大地依赖于流动相组成和百分比、梯度速率以及温度的微小变化。给出了在色谱条件下获得的FMF的紫外光谱（230至400 nm）。列出了FMF在320、335和345 nm处的相对响应因子及其在手工压榨和市售浓缩橙汁和柑橘汁中的浓度。讨论了样品间发现的FMF浓度差异。
