Measurement of Nitrophenols in Rain and Air by Two-Dimensional Liquid Chromatography-Chemically Active Liquid Core Waveguide Spectrometry

We report a novel system to analyze atmospheric nitrophenols (NPs). Rain or air sample extracts (1 mL) are preconcentrated on a narrow bore (2 mm) aliphatic anion exchanger. In the absence of strong retention of NPs exhibited by aromatic ion exchangers, retained NPs are eluted as a plug by injection of 100 µL of 0.1 M Na 2 SO 4 on to a short (2 × 50 mm) reverse phase C-18 column packed with 2.2 µm particles. The salt plug passes through the C-18 column unretained while the NPs are separated by an ammonium acetate buffered methanol-water eluent, compatible with mass spectrometry (MS). Environmental occurrence of nitrophenols (NPs) was first reported 35 years ago; 1,2 their toxicity to plants and humans has since led to continued attention. [3][4][5][6] Many NPs (especially 3-methyl-4-nitrophenol (3-Me-4-NP)) are potent vasodilators; 7 2-NP can reduce the oxygen carrying capacity of blood; 8 4-NP and 2,4-dinitrophenol (2,4-DNP) are cytotoxic, mutagenic, and likely carcinogenic. 9 4-NP, routinely found in diesel exhaust aerosols, is both estrogenic and antiandrogenic. 10 Many NPs cause headache, shortness of breath, nausea, fever, and peripheral numbness. 1 Some NPs affect plant cell metabolism even at a 10 µM concentration by uncoupling oxidative phosphorylation; 11 some decrease transpiration 12 and inhibit uptake of nutrients 13 and growth. 14 Phytotoxicity of NPs may contribute to forest decline; 11 compared to healthy leaves, higher NP levels are found on damaged ones. 15 NPs are also toxic to algae and fish. 16 Atmospheric NPs have both primary and secondary sources. 8 Primary sources include industrial raw materials or intermediates involved in the manufacturing of plastics, pharmaceuticals, disinfectants, dyes, explosives, herbicides, and insecticides; the sources stem from the use or disposal of these products, combustion of coal and wood, and notably, internal combustion engine exhaust