Identification of Organic N-Chloramines In vitro in Stomach Fluid from the RatAfter Chlorination

摘要

When (36)Cl-N-cholorpiperidine (NCP) (300 mg/L as Cl2) was mixed with stomachfluid from laboratory rats (fasted either 24 or 48 hr) and incubated in the dark for 30 min at 37 C and at higher pH values, approximately one-third was reduced to chloride and between 7% and 63% of the radiolabel was found to chromatograph in a manner distinctly different from (36)Cl-chloride of (36)Cl-NCP. The new fraction is referred to as the (36) Cl-chloroorganic fraction. The remainder of the radiolabel was associated with (36)Cl-NCP. Varying concentrations of (36)Cl-NCP (3-200 mg/L as Cl2) have been incubated for 30 min at 37 C with stomach fluid at varying pH on the product distribution. At low pH values a threshold concentration of approximately 100 mg/L active chlorine was measured below which all chloramine was reduced to (36)Cl-chloride. As the pH and concentration of (36)Cl-NCP were increased, the percentage of chloramine reduced to chloride decreased. Using concentrations between 110 and 120 mg/L (Cl2) 7% and 4% of the label was associated with the (36)Cl-chloroorganic fraction at pH 7.1 and at pH 2.2, respectively.