Fumigant Residues, Determination of 1,2-Dibromo-Ethane in Air and as Residue in Fruits

Abstract

were quite pronounced. The first dilution almost eliminated decomposition and produced a corrected CS2 reading of 244 units, approximately the reading which would be expected from 25.3 mg. of CS2 per liter when inhibition is complete (Figure 4). The first dilution of "Fire inhibited" 80:20, which contained 1% re-pentane, completely eliminated decomposition and produced a corrected CS2 reading of 245 units. The joint inhibitory effects of CCh and pentane apparently raised the lower limit of the critical CS2 concentration range above that for CS2 in 80:20 without pentane. FUMIGANT RESIDUES AcknowledgmentThis study was supported in part by a research grant from the Frontier Chemical Co., Wichita, Kan. The valuable counsel of C. C. Roan and the assistance of Carl S. Bulger are gratefully acknowledged. Literature Cited(1) Baldridge, J. R. (to Diamond Alkali Co.). U. S. Patent 2,895,870 (Julv 21, 1959).(2) Cotton, R. T., "Pests of Stored Grain and Grain Products," p. 208. Burgess, Minneapolis, Minn., 1956.

Analytical methods for the determination of fumigants

“…The intensity of the resulting solution was measured at 470 mf-L. Recoveries of 15.3 mg. of EDB were 97 to 103 percent, and of 49.7 mg. of EDB were 97 to 100 percent. DUMAS (1962) extended the MB method of DUMAS and LATIMER ( 1962) to EDB analysis, but did not suggest the method for analysis of mixtures of the two.…”

“…in the 100-g. sample specified for the method. DUMAS (1962) used the method of KENNETT and HUELm (1957) for the extraction and refluxing steps, but then determined the bromide level by coulometric titration. BIELORAI and ALUMOT (1965) utilized only the extraction by steam distillation, then analyzed the benzene layer by GLC.…”

“…This calculation would not be valid were any organic MB present as a residue, but the likelihood of this has been shown to be small. DUMAS (1962) apparently used the same approach, although he did not present directions for calculation. The sample was treated with alcoholic sodium hydroxide and ashed and the bromide determined by iodimetric titration.…”

Air Pollution

“…The samples were collected and concentrated on silica gel, flushed with nitrogen into a Saran plastic bag and then transferred to the infrared cell. Coulometric titration for bromide has been used to determine 1,2-dibromoethane after its absorption in methanolic sodium hydroxide (74). The feasibility of using polarographic techniques was investigated for the analysis of several low-molecular-weight chlorinated hydrocarbons in air (71).…”