Three TLC methods were used for an initial screening of some common plant triterpenoids and phytosterols in cuticular wax extracts of different vegetables (zucchini, eggplant, tomato, red pepper, mangold, spinach, lettuce, white-colored radicchio di Castelfranco, raddichio Leonardo, white cabbage, red cabbage and savoy cabbage). The preliminary experiments showed that the studied vegetables are potential sources of triterpenoids and phytosterols. To identify the compounds present in the extracts with high certainty, the first TLC–MS2 method was developed for the analysis of eight triterpenoids (lupeol, α-amyrin, β-amyrin, cycloartenol, cycloartenol acetate, lupeol acetate, lupenone and friedelin) and two phytosterols (β-sitosterol and stigmasterol). This method takes the advantages of: (1) a satisfactory separation of the target compounds; (2) their differentiation according to the band colors; and (3) the potential of their discrimination by the acquired first-order mass (MS) and product ion (MS2) spectra. Since the closely eluting compounds have complex and similar MS2 spectra, distinguishing between them was possible by the proposed characteristic ions. Using a custom-built mass spectral library, the head to tail MS2 spectra comparison of sample test solution zones and standard aided the compound identification. In addition to the molecular mass information, the developed atmospheric pressure chemical ionization method (APCI) in positive ion mode provided structural information, regarding the presence of functional group in the molecule. This approach resulted in many positively assigned compounds in the investigated vegetable waxes, from which more than a half are reported for the first time.
COBISS.SI-ID: 5635354
The recently developed comprehensive TLC × GC technique using headspace sampling is presented. The main advantage of this approach, as demonstrated in lipid analysis, is the possibility to include a transesterification step of glycerides into fatty acid methyl ester derivatives (FAME) because no particular constraints in terms of operational time between TLC and GC are present. Besides being a relatively low-cost solution, TLC × GC by means of headspace sampling provides many benefits in terms of flexibility of separation conditions and modulation sampling width. The technique provides over two orders of magnitude of linear range with TLC sample loads of about 1 mg with good reproducibility and accuracy, as demonstrated by multiple headspace extraction (MHE) tests. The technique is a viable alternative to the established but more expensive HPLC × GC technique. The useful range of TLC × GC in terms of analyte volatility can be further extended with a future development of devices based on thermal desorption.
COBISS.SI-ID: 5728538
Brewed tea of chamomile flowers (Matricaria recutita L.) (Asteraceae) has been extensively consumed for centuries due to either its pleasant taste or medicinal purposes. On the other hand, the major problem is difficulty in distinguishing the genuine specimen when supplying chamomile through nature-picking. Consequently flowers of other Asteraceae members resembling to chamomile in appearance may frequently be practiced by lay people or marketed in spice shops or bazaars. Evidently detection of such adulterations plays a vital role in terms of public health to avoid risk of toxicity (i.e. pyrazolidin alkaloids) and ineffective treatments (lack or insufficient concentration of the active constituents). This work presents either development and validation of a high performance thin-layer chromatographic (HPTLC) method for apigenin 7-O-glucoside which is one of the active markers in chamomile flowers or its application for the fingerprint discrimination of chamomile-like materials i.e. Anthemis spp., Bellis spp., Chrysanthemum sp. and Tanacetum sp. gathered by local people assuming as chamomile. Separation was performed on the silica gel 60 NH2 F254s HPTLC plates using the developing solvent system of ethyl acetate–formic acid–acetic acid–water (30:1.5:1.5:3, v/v/v/v). The proposed HPTLC method may also be a leading guide for the quality assessment of chamomile tea products on the market.
COBISS.SI-ID: 5627162
The anthocyanin composition of blue (Triticum aestivum L., cv. Skorpion) and purple wheat (Triticum aethiopicum JAKUBZ cv. Abyssinskaja arrasajta cv. Abyssinskaja arrasajta), cultivated in the Czech Republic, and of the prepared whole blue and purple wheat bread was determined. In blue and purple wheat, 19 and 26 anthocyanins, respectively, were tentatively identified by new method based on liquid chromatography and mass spectrometry (LC-MS). The total content of anthocyanins determined in blue and purple wheat was 9.26 and 13.23 mgkg−1, respectively. The breads were baked at 240 and 180 °C. Some significant differences in anthocyanins content were observed between breads prepared at different baking temperatures. The content of cyanidin-3-glucoside, delphinidin-3-glucoside and pelargonidin-3-glucoside was determinated in starting material, whole meal flours and baked breads. These kinds of wheat are suitable for baking bread, since intake of anthocyanins may play an important role in the prevention of human diseases.
COBISS.SI-ID: 4541560
This chapter describes two techniques, which are based on the use of centrifugal force: forced-flow layer liquid chromatographic technique - rotation planar chromatography (RPC; centrifugal layer chromatography) and forced-flow solid-liquid extraction technique - rotation planar extraction (RPE). The theoretical aspects of RPC, development and the state of the art of the instrumentation, characteristics of RPC techniques and practical aspects of RPC, preparation of chromatographic plates, circular, anticircular, and linear modes of the separations, as well as fully off-line, on-line, and mix mode separations are also discussed. Classification of different technical solutions, multiple developments, as well as several applications in the field of analytical, micropreparative, and preparative separations using planar layers and planar columns are also described. A multifunctional technical solution that enables the RPE, analytical and preparative separation of natural compounds from different plant matrices is also demonstrated.
COBISS.SI-ID: 5829146