Linear relationships between moisture (as received, W-l(i), hygroscopic, W-h(a), and total, W-l(i) as well as volatile matter content (V-i) and higher heating value (HHVi) versus the respective ashcontent (A), were observed for Vladimir lignite. Equations, errors and correlation coefficients are given.

Linear relationships between higher heating value (HHV) (14 samples) and volatile matter content (VM) (15 samples) is. ash content (4) of Vladimir lignite (Moisture free) were ill vestigated. Both straight lines have high coefficients coefficients (-0.998 for HHV -0.999 for VM). Their equations are: HHV= (25.71 +/- 0.94) - (0.312 +/- 0.022)A and VM = (55.05 +/- 0.80) - (0.481 +/- 0.01)A.

The paper approaches problems regarding the influence of the composition and structure on the properties of PbS thin films. Films with high photosensitivity are obtained from solutions containing oxidants, reducing agents or by treating the obtained films in solutions containing oxidants.

The review presents some considerations on applications of statistics in analytical chemistry such as the statistics of the point, data analysis by regression, correlation and self correlation, dispersional analysis and ANOVA model, validation of statistic hypothesis.Statistics have undergone an enormous impact from microelectronics, in the form of microcomputers and hand-held calculators. These have brought difficult statistical procedures within the reach of all practising scientists. The availability of the tremendous computing power naturally makes it all the more important that the scientist applies statistical methods rationally and correctly.

The 'Simplex' and 'Prisma' methods have been compared for optimization of the mobile phase used far the separation of a mixture of 1,4-benzodiazepines. The objective function used contains more than one term and even a second degree term.

The aim of this paper is to show that the best way in the optimization of a mobile-phase system used for the separation by TLC is the choice of a mixed objective function. The proposed function was used for the practical search for a new solvent system in the case of a mixture of some synthetic organic compounds from 3,5-pyrazolidine-dione class. The practical way was a simplex algorithm used in two dimensions.

The present paper attempts to demonstrate that Information Energy, and informational parameter simpler in its mathematical expression, has a resolution character very similar to entropy (amount of information) and may be efficiently used in analytical chemistry and mainly in thin layer chromatography. This informational parameter permits the calculation of the informational correlation (IC) and the informational correlation coefficent (ICC), two main values for the characterization of the functionality that exists between two systems or two methods which belong to different conditions of periods of time.