Description Field of the Invention:
Import into RefWorks 1. Introduction The numerous sources of hydrocarbons combined with the variety of available techniques and analytical methods have created confusion among the end users of data in regards to the appropriate methodologies.
Users, government laboratories and private laboratories disagree on the scope, range of application and quality of information obtained from using different methods [ 1 ].
Due to recognized differences and complexity of biopharmaceuticals and other products [ 2 ], qualitative and quantitative analysis is fundamental to pharmaceutical product development [ 3 ] and food manufacturers for quality control, purity determination, and for the detection of adulterants [ 4 ].
Determining the degree of fatty acid unsaturation of a product is difficult because foods can contain a complex mixture of saturated, monounsaturated, and polyunsaturated fatty acids with a variety of carbon chain lengths [ 4 ].
This situation can be circumvented by analytical chemistry which deals with methods for determining the chemical composition of samples.
It is thus necessary to calibrate each instrument or equipment and devise a specific method for the analysis of each sample type.
Analytic method development and validation are key elements of any product development program [ 3 ]. Method validation has a long history in the pharmaceutical and biopharmaceutical industries [ 2 ]. Method development and validation of a process is needed to confirm that the analytical procedure employed for a specific test is suitable for its intended use.
It helps to improve the reliability, consistency and accuracy of analytical data [ 5 ]. The major stages of a typical analytical method processing are [ 5 ]: GC injector, oven and detector temperature settings, gas pressure and flow rate, retention time definition etc.
Some analytical methods include thin layer chromatography TLChigh-performance liquid chromatography HPLC coupled with detectors such as refractive index RI detector, flame ionization detector FIDdensity detector, evaporative light scattering detector ELSDand mass spectrometer detector. These techniques have been employed to identify and quantify glycerides and FAME.
All these techniques require long analytical procedures and in some cases co-elution of components is verified, such as in mixtures containing low-molecular weight triglycerides TG and high molecular weight diglycerides DG [ 6 ].
The discovery of gas phase chromatography is credited to Archer John Porter Martin and Richard Laurence Millington Synge who published the theory of separation chromatography in [ 78 ].
The GC technique revolutionized the study of lipids by making it possible to determine the complete fatty acid composition of a lipid in a very short time [ 910 ].
Gas Chromatography seems to be the most appropriate method for qualitative and quantitative analysis of isolated lipid extracts. Palm oil from Elaeis guineensis Jacq. Crude palm oil CPO contains much saturated fatty acid palmitic acid considered to be detrimental to health.
Nutritionally, saturated fats are of particular concern, because an excess in the diet leads to their accumulation in the cardiovascular system, resulting in several health related problems.
CPO analysis by GC is required for the appreciation of variability of its fatty acids composition among parents and progeny in view of creating improved oil palm breeding materials that will produce oil of better quality [ 4 ].
Capillary GC-FID is widely used for the quantitative analysis of hydrocarbon compounds and oil analyses [ 11 ].
For precise quantitative analysis, it is essential to calibrate the GC—FID system using calibration standards for each analyte.
The response factor method determined by the analysis of standard materials or other methods prior to measurement of the analytes is also used for calibration of the GC—FID.
The FID response for hydrocarbons is generally proportional to the carbon number of the analyte [ 12 ]. Quantitative analysis of test compounds is sometimes carried out using one of the compounds in the samples as an internal calibration standard, and the analytical results compared with the reference values.
Such calibration method is known as primary ratio method. In this system, only one standard material is required and the cost for analysis is greatly reduced compared to the conventional calibration method using calibration standards for each analyte [ 12 ].
The four critical components for a method are: During the preliminary method development stage, all individual components should be investigated before the final method optimization.
This gives the scientist a chance to critically evaluate the method performance in each component and streamline the final method optimization [ 3 ].CHEMISTRY IN PERSPECTIVE by Adrian Faiers MA (Oxon) (an electrostatic approach for bored and confused A-level chemistry or other senior school chemistry students).
Withdrawn Standards. ANSIZ American National Standard for Personal Protection - Protective Footwear.
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The simplest is a Fischer esterification, which uses a carboxylic acid and an alcohol together with an acid catalyst. This forms an ester and water, so some method must be employed to force the reaction to the right, typically removal of water or by using a large excess of a reagent.
A test for blood sugar suitable for diabetics should have a similar ease of use. This brings us (via aldehydes) to the topic of reducing sugars, since they are the basis of a historically important color-based test for blood glucose. Three Visual “Tests” For The Presence of Aldehydes.
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In the preparation of ethyl esters using anhydrous ethyl alcohol and hydrogen chloride catalyst, the rate of esterification of straight-chain fatty acids from propionic through stearic is substantially constant: branching of the fatty acid chain causes retardation.