Search results for "Halal"
showing 10 items of 28 documents
o-Phthalaldehyde–N-acetylcysteine polyamine derivatives: formation and stability in solution and in C18 supports
2001
A comparative study of different derivatization procedures has been performed in order to improve the stability of the reaction products o-phthalaldehyde-N-acetylcysteine (OPA-NAC) polyamines. Procedures such as solution derivatization, solution derivatization followed by retention on a packing support, derivatization on different packing supports and on-column derivatization, have been optimized and compared. The degradation rate constant (k) of the derivative was dependent on the procedure used and on the analyte. For the spermine (the most unstable isoindol tested) k was 8 +/- 2 x 10(-2) min(-1) in solution versus 7.7 +/- 1.1 x 10(-4) min(-1) on the (C18) solid support. The results obtai…
Enhancement of retention predictions in reversed-phase liquid chromatography using reference compounds
2004
Abstract The use of reference compounds to correct errors associated with the preparation of mobile phase is studied, in order to enhance modelling of retention for optimisation purposes in reversed-phase liquid chromatography. The method fits individual retention models for a set of reference compounds, which are present in all injections. In second step, mobile-phase composition is corrected for each chromatogram, according to the fitted models of the reference compounds. The enhanced precision provided by the large number of replicates for the reference compounds is partially propagated to the retention models of the analytes. The approach is assayed in the separation of amino acids, aft…
More about sampling and estimation of mercaptans in air samples
2013
[EN] Several strategies have been developed for sampling and determination of volatile thiols. The selectivity and sensitivity of the proposed methodologies are achieved by using a specific derivatizing reagent. The different procedures assayed are based on air sampling followed by derivatization of the analytes with OPA and isoleucine in alkaline solution. The derivatization products are separated and determined by liquid chromatography and fluorescence detection. To start, the derivatization conditions and stability of the derivates have been studied in order to establish the storage conditions. In general, the strategies studied consisted on trapping and detivatization the thiol compound…
Evaluation of the proteolysis degree with the o-phthalaldehyde/N-acetyl-L-cysteine reagent
1990
The o-phthalaldehyde/N-acetyl-L-cysteine (OPA-NAC) reagent is applied to the spectrophotometric evaluation of the proteolytic activity of enzymes. The high stability of the OPA-NAC isoindoles makes a strict control of the time of reaction unnecessary. A mathematical expression is proposed to calculate proteolysis degrees, where the absorbance decrease of the OPA-NAC derivative of the protein itself during the hydrolysis process is taken into account. The method is applied to bovine serum albumine, caseine, lysozyme, lactoglobuline and protamine sulphate as substrates, and pronase, papaine, trypsin and chymotrypsin as enzymes.
Azacoccones F-H, new flavipin-derived alkaloids from an endophytic fungus Epicoccum nigrum MK214079.
2020
Abstract Three new flavipin-derived alkaloids, azacoccones F-H (1–3), along with six known compounds (4–9) were isolated from the endophytic fungus Epicoccum nigrum MK214079 associated with leaves of Salix sp. The structures of the new compounds were established by analysis of their 1D/2D nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectroscopy (HRESIMS) data. The absolute configuration of azacoccones F-H (1–3) was determined by comparison of experimental electronic circular dichroism (ECD) data with reported ones and biogenetic considerations. Epicocconigrone A (4), epipyrone A (5), and epicoccolide B (6) exhibited moderate antibacterial activity again…
Some observations on the automation by flow injection analysis of the spectrophotometric determination of amino acids and proteins witho-phthalaldehy…
1992
Automation by flow injection analysis with Spectrophotometric detection of the determination of total amino acids and proteins witho-phthalaldehyde is not straightforward. The use of spectrophotometry, instead of spectrofluorimetry, and of N-acetyl-L-cysteine, instead of the conventional mercaptoethanol is advantageous because of the lower variability of absorptivities with respect to fluorescence yields, and the larger stability of the derivatives. Under adequate working conditions and with leucine as reference, the procedure can be used for the evaluation of total amino acids. A similar procedure is proposed for the analysis of proteins in a sample. Limits of detection are ≈ 1 × 10−5M for…
Derivatization of ephedrine with o-phthaldialdehyde for liquid chromatography after treatment with sodium hypochlorite.
2000
The usefulness of the reaction with NaClO followed by derivatization with o-phthaldialdehyde (OPA) and N-acetyl-L-cysteine (NAC) has been investigated for the chromatographic analysis of ephedrine. The influence of parameters affecting the two-stage reaction has been evaluated, including concentration of NaClO, time of reaction, temperature and pH. On the basis of these studies, conditions for the pre-column and (automated) post-column determination of ephedrine are presented. The described conditions have been applied to the measurement of ephedrine in the concentration intervals 0.2-20.0 microg/ml and 2.0-50.0 microg/ml for the pre-column and post-column methods, respectively. The possibi…
Sunnītu musulmaņu pārtikas lietošanas teoloģiskie un praktiskie priekšnosacījumi (halal) un to īstenošanas iespējas Latvijā
2022
Korāns raksturo islāmticīgos, kuru pienākums ir pārtikā lietot tikai halal pārtiku, tā kā islāms nav tikai rituālu reliģija, tas ir dzīvesveids. Tomēr mūsdienu multikulturālās sabiedrības vidē ir jādefinē juridiskie, ekonomiskie un teoloģiskie priekšnosacījumi halal produktu pieejamībai un sertifikācijai. Islāmā pārtikas lietošana tiek uzskatīta par Dieva pielūgsmes jautājumu, tāpat kā rituālas lūgšanas. Šajā darbā es apgalvoju, ka Latvijas sabiedrībā trūkst izpratnes par halal pārtikas izšķirīgo nozīmi, pēc likuma noteiktās reliģijas brīvības praktizēšanai ikdienā. Lai to pierādītu, es piedāvāšu padziļinātu Korāna hermeneitiku, analizējot ēdiena lomu, aizliegtos, atļautos un šaubīgos produ…
Different forms of trigeminal autonomic cephalalgias in the same patient: description of a case.
2010
The trigeminal autonomic cephalalgias (TACs), including cluster headache, paroxysmal hemicrania and SUNCT, are characterized by the cardinal combination of short-lasting unilateral pain and autonomic phenomena affecting the head. Hemicrania continua (HC) shares many clinical characteristics with TACs, including unilateral pain and ipsilateral autonomic features. Nevertheless, HC is separately classified in the revised International Classification of Headache Disorders (ICHD-II). Here, we describe the case of a 45-year-old man presenting an unusual concurrence of different forms of primary headaches associated with autonomic signs, including subsequently ipsilateral cluster headache, SUNCT a…
Red ear syndrome in children: Review of literature and report of three cases
2020
Abstract Background Red ear syndrome (RES) is a neurological syndrome that is characterized by attacks of redness and pain that is localized in the earlobe, accompanied by a burning sensation, swelling or otalgia. The exact pathophysiology of RES is not known. Several pediatric cases have been described. They show an extreme variability in clinical presentation and therapeutic response, and therefore there are numerous difficulties in the diagnostic-therapeutic approach and in the comprehension of the physiopathology. The goal of this report is to present three clinical cases of red ear syndrome in children. These cases show various characteristics that can give useful indications regarding…