Gas chromatography/mass spectrometry with chemometric methods for the determination of fatty acid profiles in herbal oils.

The conventional method for analyzing fatty acid is gas chromatography (GC) with polar capillary columns. However, owing to the high cost and the sensitivity of these columns to the presence of water and oxygen, these columns are not the best choice for separation. Also, analyzing long-chain acids (>C28) with polar columns is impossible. On the other hand, complete separation with nonpolar columns is not possible for some saturated, unsaturated and long-chain fatty acids. Therefore, in this study, with the help of chemometric methods, a method was developed using GC/mass spectrometry (MS) with a nonpolar column to resolve the peaks to completely separate and accurately identify and quantify fatty acids. Using this method, the fatty acid profiles of the seed oils of Sesamum indicum L, Nigella sativa, Pimpinella anisum, Linum asitatissimum L, Silybum marianum and Amygdalus communis L. var. Amara and var. Dulcis were identified. Through applying the multivariate curve resolution method after GC/MS, the C-18 fatty acids such as α-linolenic, linoleic, oleic and stearic acids were separated and quantified. Also, the total percentages of identified fatty acids increased by 1-6% after resolving overlapping peaks. Finally, the obtained percentages of saturated and unsaturated fatty acids were confirmed by reference reports.

Selective and Simple Determination of Isoquinoline Alkaloids in Papaver Species by Ion Mobility Spectrometry.

In this study, a fast and precise method for determining three opium alkaloids (morphine, codeine, and thebaine) in different parts of some Papaver species was developed and validated with a low limit of detection (LOD) of 0.05 - 0.20 mg/L. The proposed method was based on three extraction steps by alkaline aqueous solution/chloroform/acidic aqueous solution and analysis by ion mobility spectrometry (IMS) and high-performance liquid chromatography (HPLC). After optimizing IMS parameters based on an experimental design, IMS was applied to analyze the extracts of seeds, stems, leaves, and capsules of seven Papaver species collected from different regions of Iran. All prepared samples were analyzed by HPLC and IMS at the same time. Then, the obtained results of the two instrumental methods were compared. The HPLC did not detect morphine in the prepared samples, while IMS results showed trace amounts of morphine in the capsules and leaves of four Papaver species. Other results were comparable and showed that IMS is more sensitive, affordable, and faster than HPLC for alkaloid analysis.

Carrier-mediated extraction: Applications in extraction and microextraction methods.

The present review is mainly focused on the overview of carrier mediated extraction (principles and applications) being reported over the last two decades and discusses the extraction process through carriers in various extraction methods such as Bulk liquid membranes, supported liquid membranes, emulsion liquid membranes and polymer inclusion membranes. Several types of carriers such as neutral, anionic, cationic, macrocyclic and supramulecular carriers are discussed. Also their application for metal, anions, drugs and environmental compounds are investigated. Carriers have been demonstrated to be useful for the selective extraction and recovery of numerous cations and anions enhancing the extraction properties of traditional solvent extraction and ion-exchange processes. Several types of carriers have different transport mechanisms. In these mechanisms, transport configurations are addressed and emphasized and the detailed information on the type of carrier are presented along with their specific separation modes. The performance of different carriers in terms of selectivity as well as efficiency are also discussed. Finally, the application of different carriers for the extraction of various compounds are compared and reviewed. To our best knowledge no reviews have been published on carrier-mediated extraction methods.

Combination of hollow fiber liquid phase microextraction followed by HPLC-DAD and multivariate curve resolution to determine antibacterial residues in foods of animal origin.

In the present research, a carrier mediated hollow fiber based liquid-phase microextraction approach (HF-LPME) prior to high performance liquid chromatography-diode array detection (HPLC-DAD) was developed for the simultaneous determination of the antibacterial residues of four tetracyclines (TCs) and five quinolones (QNs), which are commonly used as veterinary medicines. In order to obtain high extraction efficiency, the parameters affecting HF-LPME were optimized using a three-factor and three-level Box-Behnken design under response surface methodology. This method was validated according to the recommendations of the Food and Drug Administration (FDA), and, for the first time, successfully applied to a wide range of animal source food samples such as fish, milk, and honey as well as the liver and muscles of lamb and chicken. Analytical performance was determined in terms of linearity, intra- and inter-assay precision, detection and quantification limits, matrix effect, accuracy, and drug stability in real samples. Detection and quantitation limits for the different antibiotics ranged between 0.5-20ngg(-1) and 1.25-40ngg(-1), respectively. Intra and inter-day repeatability, expressed as the relative standard deviation, were in the ranges of 3.4-10.7% and 5.0-11.5%, respectively. The procedure allows good preconcentration factors of 175-700. The results of the validation process proved that the method is suitable for determining TCs and QNs residues in surveillance programs. Finally, the applicability of the proposed method was successfully confirmed by the extraction and determination of nine antibiotics in various animal source food samples. The importance of this methodology relies on the combination of HF-LPME/HPLC-DAD second-order data with multivariate curve resolution-alternative least squares (MCR-ALS) algorithm, which improves the resolution of some overlapped chromatograms and, hence, increases the accuracy and repeatability of drug determination.