College of Pharmacy, Chung-Ang University, Seoul, Republic of Korea.
J Sep Sci. 2012 Feb;35(3):416-23. doi: 10.1002/jssc.201100670. Epub 2011 Dec 27.
The quantitative performance of a simple home-built preparative gas chromatography (prep-GC) arrangement was tested, incorporating a micro-fluidic Deans switch, with collection of the target compound in a deactivated uncoated capillary tube. Repeat injections of a standard solution and peppermint sample were made into the prep-GC instrument. Individual compounds were eluted from the trapping capillary, and made up to constant volume. Chloronaphthalene internal standard was added in some cases. Recovered samples were quantitatively assayed by using GC-MS. Calibration linearity of GC-MS for menthol standard area response against number of injections (2-20 repeat injections) was excellent, giving R(2) of 0.996. For peppermint, menthol correlation over 2-20 repeated injections was 0.998 for menthol area ratio (versus IS) data. Menthone calibration for peppermint gave an R(2) of 0.972. (1) H NMR spectroscopy was conducted on both menthol and menthone. Good correspondence with reference spectra was obtained. About 80 μg of isolated menthol and menthone solute was collected over a sequence of 80 repeat injections from the peppermint sample, as assayed by 600 MHz (1) H NMR analysis (∼100% recovery for menthol from peppermint). A procedure is proposed for prediction of number of injections required to acquire sufficient material for NMR detection.
测试了一种简单的自制制备气相色谱（prep-GC）装置的定量性能，该装置采用微流道 Dean 开关，将目标化合物收集在钝化的未涂层毛细管中。将标准溶液和薄荷样品重复注入 prep-GC 仪器中。将捕获毛细管中洗脱的各个化合物收集至恒定体积。在某些情况下，添加氯萘作为内标。使用 GC-MS 对回收的样品进行定量分析。GC-MS 对薄荷醇标准面积响应与进样次数（2-20 次重复进样）的校准线性关系非常好，R(2)为 0.996。对于薄荷，在 2-20 次重复进样时，薄荷醇面积比（与 IS 相比）数据的相关系数为 0.998。对于薄荷，薄荷酮的校准得到 R(2)为 0.972。对薄荷醇和薄荷酮进行了 1 H NMR 光谱分析。得到了与参考光谱的良好对应。通过 600 MHz (1) H NMR 分析（从薄荷中回收的薄荷醇约为 100%），从薄荷样品中序列重复 80 次进样，收集了约 80μg 的分离薄荷醇和薄荷酮溶质。提出了一种预测获得足够 NMR 检测材料所需进样次数的方法。
