Analysis of N-nitrosamines by high-performance liquid chromatography with post-column photohydrolysis and colorimetric detection.
N-Nitrosamines eluted from reversed-phase HPLC were quantitatively photohydrolysed in a UV photoreactor in aqueous solution to give the nitrite ion which could be determined colorimetrically with the Griess reagent. The chromatographic behavior of N-nitroso compounds (including 19 volatile dialkyl and 7 non-volatile N-nitrosamines) was studied on three octadecylsilane columns. The capacity factor varies linearly with the number of carbons atom of the n-dialkyl chains. N-nitrosamines bearing di-n-alkyl chains with the same number of carbon atoms could be separated with a highly polar mobile phase. The yield of photohydrolysis depends upon pH and time of exposure under UV light. The response was shown to be linear in the 0-200 ng range with a limit of detection of 8 pmoles injected for N-dialkyl nitrosamines. This limit was 20 pmoles for N-nitrosamines bearing two phenyl groups. Although N-nitrosamines could be detected at 230 nm without post-column reaction, such a reaction enhances the specificity of detection in biological matrices such as gastric juice or alcoholic beverages.
Laboratoires de Biochimie-Nutrition, Faculté de Médecine, Brest, France.
G
G
Bellec
J M
JM
Cauvin
M C
MC
Salaun
K
K
Le Calvé
Y
Y
Dréano
H
H
Gouérou
J F
JF
Ménez
F
F
Berthou
D001515:Beer / Q000032:analysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003124:Colorimetry; D005750:Gastric Juice / Q000737:chemistry; D006801:Humans; D006868:Hydrolysis; D009602:Nitrosamines / Q000032:analysis*; D010777:Photochemistry; D013056:Spectrophotometry, Ultraviolet
D009602:Nitrosamines