It is shown that activation analysis is especially suited to serve as a basis for determining the chemical similarity between
samples defined by their trace element concentration patterns. The general problem of classification and identification is
discussed. The nature of possible classification structures and their approriate clustering strategies is considered. A practical
computer method is suggested and its application as well as the graphical representation of classification results are given.
The possibility for classification using information theory is mentioned. Classification of chemical elements is discussed
and practically realized after Hadamard transformation of the concerntration variation patterns in a series of samples.
Authors:Alina Pyka-Pająk, Małgorzata Dołowy, and Katarzyna Bober
The aim of the work was the chromatographic separation of salicylic acid and their derivatives, i.e., acetylsalicylic acid, salicylanilide, salicylaldehyde, salicylamide, methyl salicylate, phenyl salicylate, 2,5-dihydroxybenzoic acid, salicylhydroxamic acid, 3,5-dinitrosalicylic acid, 3-aminosalicylic acid, 4-aminosalicylic acid, and 5-aminosalicylic acid by use of adsorption thin-layer chromatography (normal-phase thin-layer chromatography [NPTLC]) and partition thin-layer chromatography (reversed-phase thin-layer chromatography/high-performance thin-layer chromatography [RP-TLC/HPTLC]). Three qualitatively and quantitatively different mobile phases were used for the separation of salicylic acid and its derivatives. Cluster analysis (single linkage method, Euclidean distance) allowed the evaluation of the suitability of the chromatographic conditions used to separate the pairs of tested compounds. The cluster analysis data indicate that the composition of the mobile phase is fundamental in the process of separation of the analyzed compounds by use of NP-TLC. The best separation of the studied substances was observed in the case of mobile phase n-hexane—diethyl ether—acetic acid (80%) in different volume ratios. The similarity analysis of the results obtained by use of RP-TLC/HPTLC revealed that the type of chromatographic plates influences significantly the quality of separation of the tested compounds. The best conditions for the separation by RP-TLC were obtained on silica gel RP-18 F254 plates. The present study indicates that the cluster analysis represents a simple-to-use and powerful chemometric tool in the prediction of TLC separation of medically important salicylic acid derivatives under various chromatographic conditions. It can be helpful in the quality control of multicomponent synthetic preparations containing these compounds or in the chemical standardization of plant products consisting of salicylic acid and related compounds.
Biliverdin is a useful component in various aspects of biochemistry and biosynthesis, but its synthetic preparation is often
long-winded. Micro-production (and subsequent isolation) by solar photolysis and gamma radiolysis of bilirubin provides rapid
in vitro generation. Both methods are competitive, and this article discusses their merits and limitations for application
in biosynthetic research. The investigation assumed a comparative study to evaluate the relative potential of the photolytic
and radiolytic phenomena in this respect. The calculated rate of incident energy in the case of solar photolysis was roughly30.4.10-2 W, and about 5.70.10-4 W during gamma-irradiation (from a 137Cs source). In both cases the bilirubin (40 µM) degradation was pronounced in the initial few minutes of exposure, producing
respective depletion rates of approximately 6.8 µM/min and 2.4 µM/min. Overall, both applications showed declining bilirubin
concentrations close to 90%, after about 30 minutes. However, the corresponding production of biliverdin was higher by about
50% in the photolytic application. To account for heat-up effects in the photolytic application, thermal effects were studied
up to 65 °C, and it was found that, as a result of this, a reduction in bilirubin concentration of about 40% was encountered.
The species of interest were monitored spectrophotometrically, and the composite results showed that regulated production
of biliverdin is possible under certain conditions.
The equation for calculation of the activation energy of the diffusion of the evolved products through the matrix (E) from a single TG curve were proposed by solving Fick's laws. The solution is based on the similarly theory by utilizing
a Fourier number.
The proposed method was examined by using mass loss data for the dehydroxylation of some micas with and without FeO (muscovite
and its varieties and lepidolite) as determined from their TG curves. TheE values for the first stage of the dehydroxylation of these micas areE1,=85±10 kJ mol−1; for the final stageE2=380±40 kJ mol−1 and for the mass loss connected with fluorineEF=85±10 kJ mol−1.
Authors:Agnieszka Jabłońska-Wawrzycka, Barbara Barszcz, and Katarzyna Stadnicka
For a comparison of structural data and thermal behaviour of Zn(II) and Cd(II) complexes with biologically important ligand,
2-hydroxymethylbenzimidazole (L) the complex of the formula [ZnL3](NO3)2L0.67L′0.33 was prepared and characterized by elemental analysis, infrared (IR) spectra, single-crystal X-ray diffraction and thermal
analysis (where L′ = 2-carbaldehydebenzimidazole). IR and X-ray studies have confirmed a bidentate fashion of coordination
of the 2-hydroxymethylbenzimidazole to Zn(II) ion (through the nitrogen atom of heteroaromatic ring and oxygen atom of hydroxymethyl
group). The zinc ion is hexacoordinated and the shape of polyhedron can be described as pseudo-octahedron (N3O3 chromophore type). The decomposition process of studied Zn(II) and Cd(II) benzimidazole complexes in the air atmosphere proceeds
in three or four main stages and traces structures of complexes. On the basis of the first DTGmax of the decompositions the thermal stability of the complexes follows the order: [CdL3](NO3)2LEtOH0.25 < [CdL2(NO3)2] < [ZnL3](NO3)2L0.67L′0.33. As the final solid products of thermal decomposition suitable metal oxides are formed.
Authors:Yanqin Zhu, Ping Du, Shaojun Huang, Qinhong Yin, and Yaling Yang
shells preparations. The chemical fingerprints of Moringa seed shells from various regions were established and investigated by similarity analysis (SA), principal component analysis (PCA) and hierarchical clustering analysis (HCA). The combination of
Similarity Evaluation System for Chromatographic Fingerprint of TCM (Version 2004A), which was recommended by China Food and Drug Administration (CFDA). The correlation coefficient of the samples was calculated and similarity comparison was performed between
A high-performance thin-layer chromatographic (HPTLC) method for the analysis of the protostemonine from Stemona sessilifolia (Miq.) Miq. has been developed and validated. According to the HPTLC fingerprint, 12 common peaks were selected to evaluate the similarities among 10 batches of samples with RF values ranging from 0.02 to 0.95. Ten different batches of samples were stable and reliable in quality, all the similarities of which are more than 0.98. The results indicated that this method was sensitive and precise for the quality evaluation of S. sessilifolia samples.
Authors:Manrong Tan, Yongsheng Ren, Dan Yan, Xianghong Meng, Longhu Chen, Lingling Qiu, Yan Yan, Jianyu Li, and Xiaohe Xiao
detection capability of microcalorimetry for drug-damaged microbe, a typical bacteriostatic ceftizoxime sodium (CZX) and Traditional Chinese Medicine injection Shuanghuanglian (SHL) were chosen.
The similarity showed that thermogenic curve of low
Clerodendrum viscosum leaves are used in indigenous systems of medicines of mainland and maritime Southeast Asian countries for the treatment of fever, pain, dysentery, colic, and removal of Ascarids. The Clerodendrum species under study exhibit various phytochemical and morphological similarities. Therefore, it is very challenging to distinguish raw powdered materials used for therapeutic purposes. A validated high-performance thin-layer chromatography (HPTLC) method with 4 key markers, viz., 24ß-ethylcho-lesta-5,22E,25-triene-3ß-O-D-glucoside, clerodinin-A, 24ß-ethyl-cholesta-5,22E,25-triene-3ß-ol, and lupeol coupled with a chemometric analysis was used to distinguish 3 closely related Clerodendrum species, viz., C. inerme, C. multiforum, and C. viscosum. PRISMA approach was applied for effective HPTLC fingerprint development. The HPTLC-densitometry method was validated following the current International Conference on Harmonisation (ICH) guidelines. Taxonomic differentiation was established by fingerprint-based similarity analysis, a chemotaxonomic study using hierarchical clustering analysis (HCA), and principal component analysis (PCA) was done. HPTLC chromatogram similarity was calculated as correlation coefficient and congruence coefficient values, demonstrating poor similarities (0.26–0.86). However, PCA has resulted in 2 principal component (PC) loadings. PC1 separated C. multiforum, explaining 85.48% of variance mainly due to distribution of 2 triterpenoids. The present HPTLC method is coupled to marker-based quality determination of raw plants as well as discrimination of Clerodendrum species. Chemometric analysis based on 4 metabolites clearly establishes a practical identification of Clerodendrum species intended for therapeutic use.