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To achieve accurate, fast and sensitive detection of phenolic endocrine disruptors in small volume of environmental water samples, a method of dispersive liquid-liquid microextraction (DLLME) coupled with fluorescent derivatization was developed for the determination of bisphenol A, nonylphenol, octylphenol and 4-tert-octylphenol in environmental water samples by high performance liquid chromatography-fluorescence detection (HPLC-FLD). The DLLME and derivatization conditions were investigated, and the optimized DLLME conditions for small volume of environmental water samples (pH 4.0) at room temperature were as follows: 70 microL chloroform as extraction solvent, 400 microL acetonitrile as dispersing solvent, vortex mixing for 3 min, and then high-speed centrifugation for 2 min. Using 2-[2-(7H-dibenzo [a, g] carbazol-7-yl)-ethoxy] ethyl chloroformate (DBCEC-Cl) as precolumn derivatization reagent, the stable derivatives of the four phenolic endocrine disruptors were obtained in pH 10.5 Na2CO3-NaHCO3 buffer/acetonitrile at 50 degrees C for 3 min, and then separated within 10 min by HPLC-FLD. The limits of detection (LODs) were in the range of 0.9-1.6 ng/L, and the limits of quantification (LOQs) were in the range of 3.8-7.1 ng/L. This method had perfect linearity, precision and recovery results, and showed obvious advantages and practicality comparing to the previously reported methods. It is a convenient and validated method for the routine analysis of phenolic endocrine disruptors in waste water of paper mill, lake water, domestic wastewater, tap water, etc.

A simple and sensitive method for the determination of long-chain free fatty acids (FFAs) using 1-[2-(p-toluenesulfonate) ethyl]-2-phenylimidazole [4, 5-f] 9, 10-phenanthrene (TSEPIP) as pre-column derivatization reagent by reversed-phase high performance liquid chromatography with fluorescence detection and mass spectrometric identification was developed. Eleven long-chain (C20-C30) FFA derivatives were separated on Eclipse XDB-C8 column with a good baseline resolution. Studies on derivatization conditions indicate that FFA reacts rapidly and smoothly with TSEPIP in the presence of K2CO3, catalyst at 90 degrees C in N, N-dimethylformamide solvent to give the corresponding sensitively fluorescent derivatives with maximal yields close to 100% with a 5-fold molar reagent excess. The identification of 11 FFA derivatives was carried out by online post-column mass spectrometry with atmospheric pressure chemical ionization source in positive-ion mode. The contents of 11 FFAs in soil and three bryophytes (Homomallium connexum (Card.) Broth., Actinothuidium hookeri, Neckera pennata) were determined. The results indicate that the bryophyte plants enrich an abundance of FFAs from soil. The excitation and emission wavelengths of fluorescence detection were set at 260 nm and 380 nm, respectively. Linear correlation coefficients for the most FFA derivatives were higher than 0.9996, and the detection limits (at signal-to-noise of 3:1) were 26.19-76.67 fmol. The method is sensitive and reproducible for the determination of long-chain FFAs in real samples.

Aliphatic amines exist widely in nature. Therefore, quick and precise determination of aliphatic amines is of great significance. A simple and highly sensitive method based on the derivatization of aliphatic amines utilizing 1,2-benzo-3,4-dihydrocarbazole-9-acetic acid (BCAA) as the novel pre-column derivatization reagent followed by high performance liquid chromatography with fluorescence detection and online mass spectrometric identification was developed. Optimum derivatization was obtained by the reaction of aliphatic amines with BCAA at 50 degrees C for 15 min in the presence of 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDAC) in acetonitrile solvent. The condition of derivatization was mild and the yield of derivative each aliphatic amine was higher than 94%. Derivatives were sufficiently stable to be efficiently analyzed by high performance chromatography without pretreatment. On a reversed-phase BDS-C18 column, twelve aliphatic amine derivatives (C8 - C12) were separated under gradient elution with baseline resolution. The precise determining aliphatic amines from soil and wastewater samples was obtained by post-column online mass spectrometric identification with atmospheric pressure chemical ionization (APIC) source under positive mode detection. The established method exhibited excellent reproducibility and recovery. Linear responses were observed with coefficients over 0.999 3. The detection limits (at signal-to-noise ratio of 3: 1) were 12 - 28 fmol.