Determination of Toluene By Gas Chromatographic Method
Introduction:
Gas chromatography is a specifically gas-liquid chromatography that involves a sample being vaporized and injected onto the head of the chromatographic column. The sample is transported through the column by the flow of inert, gaseous mobile phase, which is usually an inert gas such as helium or an unreactive gas such as nitrogen. The column itself contains a liquid stationary phase, which is a microscopic layer of liquid or polymer on an inert solid support, inside glass or metal tubing that is adsorbed onto the surface of an inert solid. The instrument used to perform gas chromatographic separations is called a gas chromatograph.
A gas chromatograph is a chemical analysis instrument for separating chemicals in a complex sample. A gas chromatograph uses a flow-through narrow tube known as the column, through which different chemical constituents of a sample pass in a gas stream (carrier gas, mobile phase) at different rates depending on their various chemical and physical properties and their interaction with a specific column filling, called the stationary phase. As the chemicals exit the end of the column, they are detected and identified electronically. The function of the stationary phase in the column is to separate different components, causing each one to exit the column at a different time (retention time). The carrier gas flow rate and temperature are facters to change the order or time of retention.
In Gas chromatography, there are two analysis including Qualitative analysis and Quantitive analysis. In this experiment, Quantitive analysis is used which is the area under a peak is proportional to the amount of analyte present. By calculating the area of the peak using the mathematical function of integration, the concentration of an analyte in the original sample can be determined. Concentration can be calculated using a calibration curve created by finding the response for a series of concentrations of analyte, or by determining the response factor of an analyte. The response factor is the expected ratio of an analyte to an internal standard and is calculated by findng the response of a known amount of analyte and a constant amount of internal standard (a chemical added to the sample at a constant concentration, with a distinct retention time to the analyte).
A typical GC analysis takes more time; sometimes a single sample must be run more than an hour according to the chosen program; and even more time is needed to "heat out" the column so it is free from the first sample and can be used for the next.
Toluene is a clear and water-insoluble liquid with the typical smell of paint thinners, redolent of the sweet smell of the related compound benzene. It is an aromatic hydrocarbon that is widely used as an industrial feedstock and as a solvent.
Introduction:
Gas chromatography is a specifically gas-liquid chromatography that involves a sample being vaporized and injected onto the head of the chromatographic column. The sample is transported through the column by the flow of inert, gaseous mobile phase, which is usually an inert gas such as helium or an unreactive gas such as nitrogen. The column itself contains a liquid stationary phase, which is a microscopic layer of liquid or polymer on an inert solid support, inside glass or metal tubing that is adsorbed onto the surface of an inert solid. The instrument used to perform gas chromatographic separations is called a gas chromatograph.
A gas chromatograph is a chemical analysis instrument for separating chemicals in a complex sample. A gas chromatograph uses a flow-through narrow tube known as the column, through which different chemical constituents of a sample pass in a gas stream (carrier gas, mobile phase) at different rates depending on their various chemical and physical properties and their interaction with a specific column filling, called the stationary phase. As the chemicals exit the end of the column, they are detected and identified electronically. The function of the stationary phase in the column is to separate different components, causing each one to exit the column at a different time (retention time). The carrier gas flow rate and temperature are facters to change the order or time of retention.
In Gas chromatography, there are two analysis including Qualitative analysis and Quantitive analysis. In this experiment, Quantitive analysis is used which is the area under a peak is proportional to the amount of analyte present. By calculating the area of the peak using the mathematical function of integration, the concentration of an analyte in the original sample can be determined. Concentration can be calculated using a calibration curve created by finding the response for a series of concentrations of analyte, or by determining the response factor of an analyte. The response factor is the expected ratio of an analyte to an internal standard and is calculated by findng the response of a known amount of analyte and a constant amount of internal standard (a chemical added to the sample at a constant concentration, with a distinct retention time to the analyte).
A typical GC analysis takes more time; sometimes a single sample must be run more than an hour according to the chosen program; and even more time is needed to "heat out" the column so it is free from the first sample and can be used for the next.
Toluene is a clear and water-insoluble liquid with the typical smell of paint thinners, redolent of the sweet smell of the related compound benzene. It is an aromatic hydrocarbon that is widely used as an industrial feedstock and as a solvent.
