Quantitative analysis by phosphorus-31 nuclear magnetic resonance spectrometry

Determination of silver in precipitation by furnace atomic absorption spectrometry

“…furnace surface temperatures in excess of ~1700 K were required to maximize absorbance. This agrees well with the results reported by Woodriff et al (4). The dropoff in absorbance with tube lengths greater than ~17 mm was due largely to the inability to uniformly heat these to this temperature level in less than 10 s. Heating for longer periods caused rapid decay of the furnaces.…”

“…As noted above, triplicate sample analyses involving the entire procedure were typically reproducible to ±20% at the 1 x 10"5 µg/mL level and improved to ±10% at ten times that level. This compares favorably with an average relative standard deviation of 40% reported by Woodriff et al (4). The detection limits attainable were largely determined by reagent blanks; these were typically less than 1 X 10"6 µg/mL.…”

“…The concentration of silver in natural, unseeded, precipitation is usually on the order of 10-6-10-5 Mg/mL (2,3). Silver levels reported in seeded precipitation range upward to, but rarely exceed, 10'3 µg/mL (4), Warburton (3) measured silver in snow collected 80 km downwind of a seeding program in the Sierra Mountains and noted that seeding approximately doubled the silver background level of 4 X 6 pg/mL. The determination of these ultratrace concentration levels requires an analytical method of unusually high sensitivity.…”

Determination of lead in atmospheric particulates by furnace atomic absorption

“…Apparatus and Materials. The spectroscopic apparatus and the atomic absorption furnace used have been described previously (15,16), and for the sake of brevity will not be repeated here.…”

Determination of sub-nanogram amounts of silver in rain water by stable isotope dilution

“…Others have reported the analysis of Ag in natural water in sub-nanogram quantities by neutron activation (1), flame atomic absorption with microsampling boat (2, 3), and flameless atomic absorption (4,5). Neutron activation analysis is subject to rather large reproducibility errors (on the order of ±25% at nanogram concentrations) and is expensive.…”