Analysis of dimethyl hydrogen phosphite and its stability under simulated physiological conditions

Journal Article · · Journal of Analytical Toxicology; (USA)

DOI:https://doi.org/10.1093/jat/12.6.334· OSTI ID:7196616

Nomeir, A A; Burka, L T; Matthews, H B ^[1]

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1. National Institute of Environmental Health Sciences, Research Triangle Park, NC (USA)

In a study by the National Toxicology Program, dimethyl hydrogen phosphite (DMHP) was shown to cause dose-related neoplastic lesions in the lungs and forestomachs of Fisher 344 rats. This investigation was carried out to study the stability of this carcinogen under conditions similar to those that the chemical may encounter in the physiological environment. To carry out these studies, capillary gas chromatography was utilized to analyze DMHP. The method was linear over a range of 10 to at least 1000 ng. High-performance liquid chromatography (HPLC) also was used to analyze DMHP and its degradation products. In aqueous solution, DMHP was stable for a period of time before degradation began. Once the process began, degradation continued until 10-20% of the original concentration was reached and further decomposition was minimal. At 10% concentration in 0.1M phosphate buffer, pH 7.4, DMHP was stable for 3.6 at 37{degree}C. This stability period increased at lower temperature, at lower DMHP concentration, and in slightly more alkaline buffer (pH 8). After the stability period, DMHP disappeared from the solution and this disappearance followed a first order kinetics with a rate dependent upon temperature, concentration of DHMP, and the pH of the solution. The half-time of disappearance of DMHP under the conditions mentioned above was 2.4 h, which increased at lower temperature, at lower DMHP concentration, and in slightly more alkaline buffer (pH 8). The decomposition products of DMHP were identified by HPLC and proton nuclear magnetic resonance ({sup 1}H-NMR) spectroscopy as methanol, monomethyl hydrogen phosphite, and orthophosphorous acid.

• OSTI ID: 7196616
• Journal Information: Journal of Analytical Toxicology; (USA), Journal Name: Journal of Analytical Toxicology; (USA) Vol. 12:6; ISSN 0146-4760; ISSN JATOD
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
CARCINOGENS
CHEMICAL PROPERTIES
CHROMATOGRAPHY
GAS CHROMATOGRAPHY
LIQUID COLUMN CHROMATOGRAPHY
NMR SPECTRA
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHYSIOLOGY
SEPARATION PROCESSES
SIMULATION
SPECTRA
STABILITY