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
Lucky numbers of Euler Lucky numbers of Euler Euler's “lucky” numbers are positive integers "n" such that for all integers "k" with , the polynomial produces a prime number. When "k" is equal to "n", the value cannot be prime anymore since is divisible by "n". Since the polynomial can be rewritten as , using the integers "k" with produces the same set of numbers as . Leonhard Euler published the polynomial which produces prime numbers for all integer values of "k" from 1 to 40. Only 7 lucky numbers of Euler exist, namely 1, 2, 3, 5, 11, 17 and 41 . The