Separation optimisation programmes

Changes one variable at a time and [X edicts separation as function of that variable Drylab 165, 166,170 

Changes one or more variables at a time and predicts separation as a function of those variables ICOS, DIAMOND 167, 168,171 

Ch iges column conditions (column dimensions, particle size and flow rate) d predicts separation for any column condition Drylab, ENHANCER 165 

Changes gradient conditions and predicts separation fa any gradient condition Drylab 153, 165,166 

Changes one oi more conditions and examines experimental chromatc rams for best separation PESOS 169, 170 

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The analysis of PAHs by fluorescence detection HPLC is often the water analysts first introduction to HPLC. The analysis of the WHO six PAHs (section 11.8.1.1) namely fluoranthene, benzo[6]fluoranthene, henzo[k]fluoranthene, benzo[a]pyrene, benzo[g/j/ perylene and indeno[l,2,3-cd]pyrene was carried out using fixed excitation and emission E wavelengths. With the advent of relatively cheap variable wavelength programmable fluorescence detectors, the detectors can be optimised for each separate PAH with a resultant lowering of detection limit. Ultratrace determination of PAHs down to 180fg of benzo[a]pyrene was reported as early as 1983. 

By far the most critical economical parameter is the yield of a bioprocess, i.e. the amount of product obtained relative to the raw materials applied, the working volume of the bioreactor and the elapsed reaction time. The yield may be improved by the use of more efficient biocatalysts as a result of screening programmes or genetic engineering as well as optimisation of downstream separation and purification techniques. 

Glass capillary column coated with methyl silicone, carbowax, 5%-phenyl-methylsiloxane are usually employed for the separation. Column temperature programming can be preliminary set by using medium ramping time of each step of increments, if the components are eluted unresolved or too far apart, the programme can be optimised. The maximum temperature for each type of column has to be carefully checked. 

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