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
Negative and positive rights after a disaster. This consideration has led ethicists to agree in a general way that positive obligations are usually junior to negative obligations because they are not reliably "prima facie". Some critics of positive rights implicitly suggest that because positive obligations are not reliably "prima facie" they must always be agreed to through contract. Nineteenth-century philosopher Frédéric Bastiat summarized the conflict between these negative and positive rights by saying: According to Jan Narveson, the view of some that there is no distinction between negative and positive rights on the ground that negative rights require police and courts for their enforcement