Extraction factorial experimental design

The simplest and cheapest procedure to obtain standards is based on selective extraction followed by crystallization. A method developed to obtain lycopene from tomato residue using factorial experimental design consisted of a preliminary water removal with ethanol, followed by extraction with EtOAc and two successive crys-talhzation processes using dichloromethane and ethanol (1 4), producing lycopene crystals with 98% purity, measured by HPLC-PDA. Using this approach, bixin was extracted with EtOAc from annatto seeds that were previously washed with... 

Evaluation of Bonded-Phase Extraction Techniques Using a Statistical Factorial Experimental Design... 

Figure 17 Separation of compounds using the optimum eluent composition achieved by factorial experimental design. Eluent hexane-dichloro methane-acetone-2-propanol (65 13 21 0.9, v/v) Compounds I, deacetyl-vinblastine II, vincristine III, N-demethyl-vinblastine IV, vinblastine V, deacetoxyvinblastine VI, leurosine the arrows show the unidentified peaks adjacent to vinblastine in the plant extract. (Reproduced by permission from Ref. 67.)...

Fractional distillation of crude pine oil, 24 510 of crude sulfate turpentine, 24 476 Fractional extraction, 10 745, 759-760 Fractional factorial designs, 8 396 amount of coverage in experimental design texts compared, 8 395t commercial experimental design software compared, 8 398t Fractional velocity plots, 10 319-321 Fractionating towers, in plant layout,... 

A research project (carried out under the former BCR and coordinated by the CID-CSIC in Barcelona, Spain) also enabled development of a supercritical fluid extraction procedure which was successfully applied to the certification of TBT in the CRM 462 [99]. The effect of extraction variables, such as extraction time, temperature and extraction agent composition, in supercritical fluid extraction have been optimized by using a factorial-fractional experimental design. Under the optimum conditions (T = 60 °C, P = 35 MPa, 5.1 mol methanol in CO2, t = 30 minutes), the TBT extraction efficiency was 82% with a coefficient of variation of 9.2% (after determination by GC-FPD). 

In many experimental design problems, it is necessary to design the trials or runs in such a way that the variability arising from some nuisance factors can be controlled. These nuisance factors (or "blocking variables ) may affect the response but are neither factors nor fixed variables. They can be analysts, instruments, reagents, sample materials, working day, etc. Let us consider the simple case of a 2 factorial design to improve an automated extraction step in a... 

Elompart et al. (2001), like Jozefaciuk et al. (2003), use a combined R D section (the preferred format in Analytical Chemistry, the journal that published this article). Their R D section describes both preliminary tests and optimization procedures. Results and discussion of the preliminary tests were presented in excerpt 4C results and discussion of the optimization procedures are presented in excerpt 5A. The optimization process used a factorial design in which five experimental parameters were systematically varied and tested to improve the saponification technique. These variables included the concentration of NaOH, the volume of NaOH, the extraction and stirring times, and the kind of SPME fiber used. 

Two algorithms are available to perform all the calculations in a very simple way, namely the Box, Hunter and Hunter (BH ) algorithm and Yates s algorithm. Both are considered below for a typical and simple example of a 2 factorial design. Assume we are studying the influence of pH (A), temperature (B) and time (C) over the yield (response in %) of the extraction of a metal from a complex analytical matrix, just before conducting the extracts to an ICP device. The levels of each factor, fixed by the analyst, are pH (A), 3 (—), 5(4-) temperature (B), 40 (-), 60 C ( + ) and time (C), 1 (-), 2h. (- -). The matrix design and the experimental data are as follows ... 

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