Determination Of Catecholamines And Nitroanilines Using High-performance Liquid Chromatography Combined With Solid-phase Extraction

With the development of industry and agriculture, human health and environmental safety were increasingly concerned about. The concentration of the neurotransmitter, such as catecholamines has important implications for human health and disease diagnosis. A large amount of poisonous chemicals, such as nitroaniline and dinitroaniline isomers are imported into environment, by means of inhalation, ingestion or skin contact, these contaminations enter into the body and interact with biomacromolecules directly or indirectly and then effect their function or genetic characteristic, hence research on the residue of nitroanilines and dinitroanilines in the environment and their environmental risk is of great importance in the environmental protection. But two types of substances, whether catecholamines in human urine, or nitroanilines/dinitroanilines in environmental water samples, content was very low, therefore requires the development of novel pre-treatment, separation and detection methods, whick could simultaneously determinate the analytes with low levels in complicated matrix such as urine samples and waste waters.In the first part, environmentally friendly sample preparation methods for chromatography analysis emerged in recent years were reviewed, the principal and procedure of these sample preparation methods were briefly introduced, application of these sample preparation methods to the separation and analysis of catecholamines were summarized, the applications of some separation and analysis methods to the biological sample for the detection of the catecholamines were summarized in detail; separation and analysis of nitroaniline isomers in environmental water samples were also reviewed, and the difficulties of these sample preparation methods combined with different instruments were also summarizedIn the second part, a high-performance liquid chromatography (HPLC)-fluorimetric detection method, combined with solid-phase extraction (SPE), was developed for the determination of four catecholamines including L-DOPA, norepinephrine, epinephrine and dopamine in urine samples. Extraction of the four catecholamines was carried out with a strong cation-exchange cartridge, the BCX. The four catecholamines were eluted by 1 mL 3M HCl. Separation of the four catecholamines was achieved by using an Agilent HPLC. The analytes were detected by a fluorimetric detector, the fluorescence intensity was measured at the excitation wavelengths of 280 nm and the emission wavelengths of 320 nm. Recoveries of the four catecholamines in the spiked urine sample were between 76.0 and 103.8% with a relative standard deviation of less than 5.4%. The limits of detection (S/N=3) determined in a spiked urine sample of 10 mL were 3.5×10-8 mol/L for L-DOPA, 6.3×10-8 mol/L for norepinephrine,4.3×10-8 mol/L for epinephrine and 1.2×10-7 mol/L for dopamine. The proposed method was applied to determine the four catecholamines in the human urine samples.In the third part, a high-performance liquid chromatography (HPLC)-ultraviolet detection method, combined with solid-phase extraction (SPE), was developed for the determination of five nitroaniline and dinitroaniline isomers including 2-nitroaniline, 3-nitroaniline,4-nitroaniline,2,4-dinitroaniline and 2,6-dinitroaniline in waste water samples. Extraction of the five isomers was carried out with a hydrophile-lipophile balance cartridge, the Oasis HLB. The cartridge was washed by a mixed aqueous solution containing 10%(v/v) acetonitrile and 10%(v/v) ethyl acetate before the five isomers were eluted by a mixture of methanol and acetic acid. Separation of the five isomers was achieved by using an Agilent HPLC and detected by a UV detector at a wavelength of 225 nm. Recoveries of the five isomers in the spiked sewage sample were between 84.6 and 94.0% with a relative standard deviation of less than 4.7%. The limits of quantification (LOQs) determined in a spiked sewage sample of 500 mL were 2.0×10-9 mol/L for 2-nitroaniline,3-nitroaniline and 2,6-dinitroaniline, and 4.5×10-9 mol/L for 4-nitroaniline and 2,4-dinitroaniline. The proposed method was applied to determine the five isomers in the real samples of acidic waste water and printing and dyeing waste water.