Procedure for fusion

Handbooks supplied by manufacturers contain valuable information for selecting instrument settings. However, in order to optimize the analyte s signal, burners should be clean and flame stoichiometry and burner position should be adjusted before each group of measurements is taken on standards and samples. 

The recommended conditions for determining the elements by AES and AAS spectrometry are given in Table 1. After a suitable burner warm-up time, one AES or AAS reading is obtained on each calibration standard and sample solution using an 8 to 10-second integration time. The process is repeated at least two or three more times to acquire an average of three or four readings for each solution. 

Calibration curves are based on AES or AAS measurements on at least five (preferably six) standards. The calibration curve, relating the average AES or AAS reading to concentration, is graphed either manually or by a suitable computer program. 

Below is shown a typical formula for calculating the percent oxide in a sample. 

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This useful annelation procedure for fusion of 2-carboxy-A -cyclohexenone systems to a preexisting ring was previously marred by the difficult accessibility of 3-oxo-4-pentenoic acid ester. An efficient synthesis of this compound has now been devised by G. Stork and R. N. Guthikonda, Tetrahedron Lett, 2755 (1972). 

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