Molecular emission cavity analysis—a new flame analytical technique

Direct current electrogenerated chemiluminescent microdetermination of peroxydisulfate in aqueous solution

“…In the meantime, several techniques have been reported for the determination of S2082" (14)(15)(16)(17)(18). For example, about 10"3 ( = mol L'1) S2082" was detected using alternating current polarography (14).…”

“…It was observed that nanogram amounts of sulfur-containing species, such as S042" and S2082", could be determined by a flame analytical technique, based on S2 emission, called molecular emission cavity analysis (MECA) (17,18). However, the MECA method is not specific for S2082" and requires an expensive instrument.…”

Determination of sulfite and sulfate in solids by time-resolved molecular emission spectrometry

“…Sulfite solutions were stabilized for several days by the addition of sufficient disodium EDTA to make them 8 x 10"4 M in Na2EDTA, and then stored in 10-mL evacuated blood collection tubes to minimize air oxidation. As suggested by Belcher (30), solutions were made 0.10 M in phosphoric acid to provide optimum conditions for molecular sulfur emission.…”

“…The cooling coil was used to ensure more reproducible sample temperatures prior to introduction into the flame, to hasten cooling between sample runs, and to thermally isolate the cavity portion of the rod during analysis. As suggested by Belcher (30), a quartz cup 6 mm in diameter and 4 mm deep was inserted in the end of the stainless steel sampling rod (Figure 2, B).…”

“…The production of molecular sulfur which has a blue emission band at about 384 nm is further stimulated by the abundance of hydrogen radicals and the relatively cool nature of the flame. Belcher and his coworkers also found that many sulfur anions differ significantly in their volatility and therefore may exhibit singular timedependent emission responses under the appropriate experimental conditions (30). By varying parameters such as cavity material and H2/N2 ratios, they were able to resolve various binary and ternary mixtures of dissolved sulfur anions, including: S0327S042" and S27S0327S042- (31,32).…”