Farmingdale, NY (PRWEB) June 25, 2013
The Spectral Bandwidth (SBW) of a spectrophotometer is the basis of establishing its ability to resolve absorption lines separated by small differences in wavelength. If a substance that requires measurement has an absorption line at 257.4nm and there is an interfering line at 260.0 nm, one needs to establish whether the spectrophotometer can resolve the two lines separately or if it "mixes" the two absorption lines into a single line. This brings about erroneous results. Toluene in Hexane is used as a reference for the calculation of SBW. The ratio of the absorption of the solution when read at a maxima (around 268.7nm) and at a minima (around 267.0nm) relates directly to the SBW of the instrument being assessed. Regular use of this technique will assure that the resolution of your instrument is within the required range for Good Laboratory Practice.
Assessing the photometric and wavelength performance of a UV/VIS spectrophotometer is a necessary part of keeping a laboratory in accordance with GLP standards which makes NSG Precision Cells' Toluene in Hexane a necessity. Understanding and accounting for how expanded uncertainties affect these measurements is a critical component of the calibration process.
NSG's Toluene in Hexane reference standard ensures accurate wavelength and absorbance results by verifying the spectrophotometer's resolution. Accurate absorbance and wavelength measurements can only be achieved if due consideration is given to the resolution of the monochromator in use. In modern instruments with grating monochromators, the resolution relates directly to the slit width chosen. The smaller the slit and associated spectral bandwidth, the greater the resolution, but the corresponding reduction in energy means the signal-to-noise ratio falls. When measuring an absorbance band in a high-resolution instrument, it is recommended that the spectral bandwidth (SBW) should not exceed 10% of the natural bandwidth (NBW) of the band. Simple checks of the resolution and bandwidth of your spectrophotometer will ensure that the best possible results are obtained for your analyses. A 0.02% Toluene in Hexane Solution is the European Pharmacopoeia's preferred method for verifying resolution of a spectrophotometer.
Toluene in Hexane is Heat-sealed in a quartz cuvette and traceable to the NIST. Resolution is measured by calculating the ratio of the peak maxima of toluene at 269nm to its peak minima at 266nm. Resulting ratio provides a measure of instrument resolution. To determine spectral bandwidth, compare ratio obtained with table provided with the standard.
The EP recommends comparing the ratio of the peak maxima at 269nm and the minimum at 266nm to determine the spectral resolution of your spectrophotometer. Determine the resolution by running the toluene in hexane against the hexane blank between 265-270nm and calculate the peak minima and maxima. Calculate the ratios of the peak to the trough and compare these results with the reference values. Please note that this is a liquid calibration filter and does not come with the same Lifetime Warranty as NSG's Solid State Standards. The NSG Toluene in Hexane filter must be recalibrated every year according to NIST guidelines.
About NSG Precision Cells
NSG Precision Cells, Inc. was founded in 1958 and has been growing ever since. NSG Precision Cells, Inc. is a well established, highly regarded quartz manufacturer and we specialize in the manufacturing of quartz flowcells, quartz flow channel cuvettes, quartz microchips, quartz cuvettes, and other quartz optical products.