Quantitative Analysis

A linearity of detector response over a range of &104 for aromatic hydrocarbons in the vapour phase has been reported. Similar linear responses were observed for more polar aromatic compounds (coumarin and phenols) and no deviations from Lambert-Beer's law were found in the range of the mass loading limits imposed by the capillary column employed. Also the linearity for nitric oxide standards has been studied in the range of 10-1800 ng at the wavelength of 213.5 nm. The standards were prepared from a standard gas tube containing 99% nitric oxide. Standard concentrations in nitrogen were prepared from the tube using Tedlar bags and gas-tight syringes. The standard curves were linear in the range studied.

Studies of day-to-day variation and repeatability have been carried out at a temperature of 110°C using a GC-UV Inscan 175 spectrophotometer linked to a dynamic dilution system for the standard concentrations and a 200 |L loop injection. The compounds determined were methanethiol and diethyl sulfide. The within-day relative standard deviations (RSD) were 2.3% (n = 7) for diethyl sulfide at a concentration of 82 p.p.m. and 3.0% (n = 7) for methanethiol at 79 p.p.m. The between-days deviations were measured for 3 months (n = 36). The RSD values were determined for the slope of the standard curves, with concentrations between 80 and 2000 p.p.m.

These between-days RSD values were 4.0% for diethyl sulfide, and 5.0% for methanethiol. These results include the errors arising from the dynamic dilution system used. In this case a photo diode array type detector was employed, which has the advantage of having a low wavelength drift.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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