Chemical ionization source, the reagent gas is present in large excess compared to the analyte. Electrons entering the source with energy around 200-500 eV will preferentially ionize the reagent gas. Then, the ion/molecule reactions produces more stable reagent ions and the resultant collisions with other reagent gas molecules will create an ionization plasma. Positive and negative ions of the analyte are formed by reactions with this plasma. The following reactions are possible with methane as the reagent gas. If ammonia is the reagent gas, For isobutane as the reagent gas, Self chemical ionization is possible if the reagent ion is an ionized
Positive and Negative Affect Schedule between the two. Previous mood scales for children have been shown to reliably capture the former relationship but not the latter; the PANAS-C was created as a tool with better discriminant validity for child assessment. Similar to the development of the original PANAS, the PANAS-C drew from terms of the PANAS-X and eliminated several terms with insufficient correlations between the term and the affective construct after preliminary analyses with a non-clinical sample of children. The final version of the measure consists of 27 items: 12 positive affect terms and 15 negative affect terms. Despite the purpose of its development, however,