Authors:A. Sheikhi-Garjan, A. Hosseini-Gharalari, M. Mahjob, M. Rashid, Q. Sabahi, M. Safari, F. Jalilyan, and R. Arbabtafti
Inc. ( 2002 ): SAS/STAT user’s guide. Version 9. 1. SAS Institute Inc., Cary, North Carolina.
Sheikhigarjan , A. , Keyhanyan , A. , Mahjoub , M. and Abdollahi , Gh. ( 2006 ): Study on efficacy and calibration accuracy of conventional
Authors:J. Mano, S. Lanceros-Méndez, A. Nunes, and M. Dionísio
Dielectric experiments are often performed in non-isothermal conditions. Thus, there is a difference between the temperature of the sample and the sensor temperature. In this work we propose and compare three temperature calibration methods based on the detection of transitions or relaxations: i) the melting of high-purity metallic standards (indium and tin), ii) the 2nd order phase transition of a ferroelectric crystal (TGS); iii) the -relaxation of an amorphous polymer (poly(carbonate)). The results obtained from the three different methods were used to construct a calibration curve for a given heating rate.
Correct calibration in planar chromatography is highly critical. If it is based on classical modes, it is nearly outside the legal limits of mathematical statistics, as we then correlate signal pairs measured in analytical systems which too often are incomparable and falsified by a strong systematic error. This may sound over critical, but the key word in the head line is “correct.” The way out is shown in this paper. It mainly means to reduce and avoid all systematic errors, the main source for a too high analytical uncertainty of quantitative results in planar liquid chromatography (PLC).The main steps to reduce the systematically PLC errors are the following:
Select the best possible area on a plate. It is in the center, not at borders.
Repair the unwanted start chromatography after sampling by a complete sample solvent removal and by focusing the already by part pre separated non-homogenous sample area.
Avoid mobile phase interactions which falsifies RF values. This means: suppress any mobile phase chamber effect simply by notusing any chamber.
Reduce drastically the signal worsening by the “second chromatography” effects during the final mobile phase removal from the plate.
Reduce as strong as possible the plate structure effects at signal integration. Multi integration at mini stepwise position movement of the integration track reduces the structure error by the number of steps.
Apply statistically tested outlier removals.
Apply mathematical statistics to qualify and quantify the data correlation of signal over substance mass in the whole range of the calibration line.
Use the statistically qualified polynomial interpolation mathematics.
This way of calibration pays back in a repeatability standard deviation of about “s = ±0.2 to ±0.05% in top PLC quantification, which can reach the best values of high-performance liquid chromatography (HPLC) quantification. The statement “PLC is a semi quantitative technique thus HPLC application is a must in many analytically important areas” is then disqualified as “nonsense.”
This contribution deals with the calibration of a DSC apparatus between −100 and 0°C using compounds with well-known temperature
and heat of transition. Only a few suitable substances are mentioned in literature. For that reason another compound, adamantane,
is proposed with a solid-solid transition at −64.56°C and a heat of reaction being 24.78 J/g.
Authors:Geert Vanden Poel, Daniel Istrate, Agnieszka Magon, and Vincent Mathot
higher scan rates requires a new approach concerning the temperature calibration of FSC's, which has been developed recently and described in DIN SPEC 91127 [ 14 ].
In this article, an FSC based on MEMS-technology is discussed: the Mettler
For a large number of DSC calibration substances the vapour pressure at room temperature or at transition temperature (whichever is the highest) is given. It is important to know the vapour pressure of substances, because a DSC measurement on a substance with a high vapour pressure requires encapsulation of the substance in a hermetically sealed crucible to prevent evaporation. Because the calibration procedure must be performed using the same type of sample pan as will be used during the actual measurements, the presented information allows one to decide which calibration substances and/or what type of sample pan should be used for calibration.
A new algorithm for calculating efficiency calibration has been implemented. It is based on orthonormal polynomial approximation and is capable of dealing with polynomials of degree up to 12 and to handle up to 20 experimental points. Additional utilities have been provided to control the calibration procedure including restriction of the maximal polynomial degree, applying corrections for coincidence summing, managing experimental data set (rejecting/restoring data from calculation) and graphical representation of the resulting curve and so on.