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اطلاعات کتابشناختی
عنوان اصلی: ميكرواستخراج و آناليز اسانسها با استفاده از تكنيك كروماتوگرافي گازي-طيف سنجي جرمي و روشهاي كمومتريكس
پدیدآورندگان : پرديس علوم-دانشگاه تهران (پديدآور)
نوع : متن
جنس : پايان نامه
صاحب محتوا :

کتابخانه دیجیتالی دانشگاه تهران

وضعیت نشر :
مشخصات فیزیکی : جلد1 - ص ط, ط, 209
خلاصه : Analysis of complex systems such as essential oils is a challenging problem to analytical chemists and pharmacologists. To our experience, GC–MS combined with the chemometric resolution techniques is the best tool for the characterization of the components of essential oils. Essential oils have been used for many years in Iran on account of the advantages of definite pharmacological activities and low toxicity. In the first study, the essential oil components of geranium oil were identified and determined using GC-MS data combined with the chemometric resolution techniques. A total of 61 components accounting for 91.51% were identified using similarity searches between the mass spectra and MS database. This number was extended to 85 components using chemometric techniques. Various chemometric methods such as MS, SBM and FSMWEFA were used for determining the number of components, pure variables, zero concentration and selective regions. Then the overlapping peak clusters were resolved into pure chromatograms and pure mass spectra using HELP method. In the second study, GC-MS combined with iterative and non-iterative resolution methods was used to characterize the essential oil components of cumin and caraway. OPR as a non-iterative and DS-MCR-ALS as an iterative method were used as auxiliary means to the analysis in the case of overlapping peaks. A total of 19 and 39 components were identified by direct similarity searches for cumin and caraway oils, respectively. These numbers were extended to 49 and 98 components, respectively with the help of chemometric techniques. As the sophisticated analytical instruments are not capable of handling sample matrices directly, a sample preparation step is required. This is a critical step in an analytical procedure. In analytical chemistry, the trend is toward simplification and miniaturization of the sample preparation step. In the third study, a novel method for extraction and analysis of volatile compounds of Artemisia haussknechtii boiss., using HD-SHLPME-GCMS has been developed. SHLPME parameters including nature of extracting solvent, extraction time, sample weight and microdrop volume were optimized. The experiments showed that this method is fast, simple, inexpensive for the analysis of essential oils. Using this method, 56 compounds were extracted and identified. In the fourth study, HD-DHLPME-GCMS has been described for the extraction and analysis of the volatile constituents of the same plant. The main parameters such as nature of extracting solvent, sampling volume, solvent volume, number of extraction cycles and syringe withdrawal rate were optimized. The proposed method that for the first time has been used for the extraction of the essential oils takes a very short time (few min) and requires a small amount of the plant material. The methods HD, HD-SHLPME and HD-DHLPME have been compared. HD-DHLPME method is superior due to its efficiency. In the fifth study, the combined extraction methods of HD-DHLPME-GC-MS was applied for determination of essential oil components of Rosmarinus officinalis. The effects of various parameters affecting the extraction efficiency were studied simultaneously. Optimization of the extraction parameters including, syringe withdrawal rate, sampling volume and sample weight was carried out by means of a 23 full factorial design. It was found that the effects and interactions of these three were significant. Therefore, a central composite design (CCD) with these factors was performed and a response surface equation was derived. The optimum conditions were obtained using the counter plots.
یادداشت :
عنوان انگليسي: Development of microextraction and analysis of essential oils using gas chromatography-mass spectrometry combined with chemometrics techniques
كتابنامه: به فارسي و انگليسي
چكيده: به فارسي و انگليسي
دانشكده شيمي
دكتري تخصصي
شناسه : oai:ut.ac.ir:thesis/1-40078
تاریخ ایجاد رکورد : 1386/7/29
تاریخ تغییر رکورد : 1387/12/24
قیمت شيء دیجیتال : دارای قیمت

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