George W. Harrington

The Determination of Nitrite and Nitrate Ions by Differential Pulse Polarography

Abstract A previously reported method for the determination of nitrite ion has been extended to include nitrate ion. Nitrate is reduced to nitrite by a cadmium column and the nitrite ion determined as diphenylnitrosamine. Cadmium interference is removed by pH adjustment and the use of KDTA.

2-Methyl-4-methoxy-1,2,3-oxadiazetidine. A correction.

Im Gegensatz zu fruheren Angaben fuhrt die Reaktion zwischen Aminen (II), Aldehyden (III) und Alkoholen (IV) mit Nitrit nicht zu den Oxadiazetidinen (I), sondern zu Nitrosaminen (V).

Radioisotopic exchange between chlorine gas and molten PbCl2KCl

Cl gas solubility in molten lead chloride- potassium chloride mixtures, temperature and KCl concentration dependence and existence of exchange process

The metabolism of N-nitrosomethylaniline.

SummaryThe distribution in the body, rate of disappearance from organs, tissues, and blood, and excretion in the urine of N-nitrosomethylaniline (NMA, N-nitrosophenylmethylamine) was investigated after various single doses given IP to rats. The compound was distributed fairly evenly throughout the body with no preferential concentration in the esophagus, its target organ for carcinogenicity. The high lipid solubility of NMA did not lead to any increased accumulation in adipose tissue. According to its rate of disappearance from circulating blood and tissues of rats, and from the whole bodies of mice after injection, NMA appeared to be rapidly metabolized. Methylaniline (MA), the parent amine, was found in the urine after administration of NMA but the amounts present were small relative to the dose of NMA. Administered MA was mainly excreted unchanged in the urine, suggesting that denitrosation of NMA could only be a minor metabolic pathway. No volatile nitrosamines were found in the urine or blood of rats given NMA, indicating that little, if any, transnitrosation could have occurred to yield these compounds.

Formation of an N-nitrosamine by oxidation.

Tolazamide, an antidiabetic drug, was found to produce N-nitrosohexamethyleneimine (NHM) upon exposure to an oxidizing agent and in the absence of a nitrosating agent. The oxidizing agents were either hydrogen peroxide or oxygen.

Estimation of the fraction of the dose of N-nitrosodimethylamine metabolized to methylamine in rats.

Despite many years of research on the metabolism of N-nitrosodimethylamine (NDMA) in rats, the significance of enzymatic denitrosation as a pathway remains unclear. To assess the role of this pathway of metabolism in rats, animals were administered NDMA by intravenous infusion at two infusion rates until steady state was achieved and the concentrations of NDMA (Css,NDMA) and methylamine (MA) (Css,MA), a product of the enzymatic denitrosation pathway, were determined in plasma. The clearance of NDMA (ClNDMA) from plasma was determined by dividing the infusion rate by Css,MA. The plasma clearance of MA (ClNDMA) was determined in a separate experiment. The fraction of the dose of NDMA metabolized by enzymatic denitrosation (fm) was calculated using the equation fm = (Css,MA*ClMA)/(Css,NDMA*ClNDMA). By this method it was estimated that 29% of the dose of NDMA was metabolized via the enzymatic denitrosation pathway. Thus enzymatic denitrosation is an important pathway in the metabolism of NDMA in rats.

The formation of N-nitrosodimethylamine and N-nitrodimethylamine from the plant growth regulator daminozide (alar)

Daminozide (Alar) was found to produce N-nitrosodimethylamine (NDMA) and N-nitrodimethylamine (NITDMA) when treated with nitrite in acidic solution. Unsymmetrical dimethylhydrazine (UDMH), the hydrolysis product of Daminozide, gave the same products. Use of 15N-nitrite and 15N-Daminozide showed that both the nitroso group of NDMA and the nitro group of NITDMA arise from the nitrite.