Background correction procedure

In AAS, systematic errors are often due to non-element specific absorption, which necessitates the use of background correction procedures. The absence of nonelement specific absorption can only be expected in the analysis of sample solutions with low matrix concentrations by flame AAS, but in furnace AAS work background correction is required particularly for matrix loaded solutions. The determination of the non-element specific absorption can be performed in several ways. 

Spectrophotometric methods for the analysis of caffeine Caffeine is quantified spectrophotometri-cally by measuring the ultraviolet (UV) absorbance at wavelengths between 270 and 280 nm. The major drawback of such methods is the presence of interfering substances. Such interferences can be reduced, but not eliminated, by using derivative techniques. Sample cleanup by various types of columns and background correction procedures is used to purify caffeine before spectrophotometric measurement. For example, in the Levine method, sample cleanup is achieved by a series of acidic and basic Celite columns. This method is adopted by AOAC for the analysis of... 

The results of the peak integration as a part of the post-detection data treatment (see Sects. 2.2.3 and A. 1.5) of the TCE MOs (see Fig.4.22) on the Mo(112) surface are discussed as a representative example. Applying the background correction procedure for EES data, introduced in this work, all five TCE related peaks of the adsorbed molecule on the surfaces can be resolved and fitted. 

The molecule correction factors Uscan,. which are a measure of the strength of the different reference absorbance spectra for the corresponding scan, are obtained by omission of the pixel at the analyte wavelength position and its neighbors, since the actual analyte absorption may not influence the background correction procedure. 

Because of the very high sensitivity of ICP-MS measurements, and the relatively constant background coimt rate, background correction procedures normally used for other plasma quantitation techniques (i.e., ICP-AES) are not required in ICP-MS measurements for accurate and sensitive analysis. However, background measurements are often used in ICP-MS as a diagnostic tool to ascertain whether the instrumentation is performing property or requires maintenance to function reliably. 

---