Multiresidue Determination of ß2-Agonists Including Phenylethanolamine A in Animal-Derived Food by Ultra-High Performance Liquid Chromatography/Tandem Mass Spectrometry.

A comprehensive ultra-high performance liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS) procedure for detection of nine ß-agonists in animal-derived food is described. The method was based on enzymatic hydrolysis with ß-glucuronidase from Helix pomatia, followed by a liquid-liquid extraction procedure with perchloric acid and a solid-phase extraction scheme using two kinds of cartridges, HLB and MCX. The influence of sample solution pH in the extraction recovery was studied, and pH 4.0 was found to give the best recovery. The analytes were eluted with methanol containing 4% ammonia. A validation procedure for quantitative analysis of ß-agonists in animal-derived food was performed. The three kinds of internal standards, d3-salbutamol, d6-ractopamine and d9-clenpenterol, were applied in the sample preparation and detection of UHPLC/MS/MS. The recoveries from spiked samples ranged between 74.9 and 106.9%. The relative standard deviations of detection were at 0.7-9.6%. The limits of detection and quantification were 0.01-0.05 and 0.03-0.20 µg/kg, respectively. The effect of sample matrix in the detection was discussed in detail.

[Determination of aniline in water by flow injection spectrophotometry].

A new flow injection analysis spectrophotometric method for the determination of aniline in water sample was introduced. It is based on the chromogenic-reaction of diazotization-coupling with 1-naphthol in basic media, and coupled with the flow injection analysis for the determination of aniline. The absorbance intensity was registered in this reaction solution at 495 nm. The volume of the sample loop, the length of the reacting coil and chromogenic coil, the flow rate of reagent, the reagent concentrations of H2 SO4, NaNO2, NaOH and 1-naphthol, and the effect of coexistence ions were studied. The calibration graph is linear in the range of 0.005-2.0 mg x L(-1). The detection limit is 0.001 mg x L(-1), and the RSD was 0.7% (c = 0.25 mg x L(-1), n = 11). The proposed method is simple, accurate, sensitive and rapid, and was successfully applied to the determination of aniline in tannery wastewater with the recoveries in the range of 98.0%-103.0%.

[Study on a new method for determining trace amounts of manganese (II) in water by flow-injection catalytic kinetic spectrophotometry].

An on-line supported flow-injection catalytic kinetic spectrophotometry new method for the determination of trace amounts of manganese(II) in water was developed. The method is based on the significant catalytic action of trace manganese on the fading reaction of potassium periodate and magneson I in the presence of nitrilotriacetic acid. The chemical and flow injection variables were optimized. The absorbance intensity was registered in this reaction solution at 560 nm. Under the optimum conditions, a standard curve with good linearity and broad linear range can be obtained in the range of 20-200 microg x L(-1), the linear equation is H(mV) = 0.170 5c (microg x L(-1))+0.125 2 (r = 0.999 3), the detection limit is 1.3 microg x L(-1), the relative standard deviation is 3.57% (n = 8), and the sampling frequency is 15 samples per hour. The interference of foreign iron was studied. Satisfied results were achieved with the proposed method to analyze the Mn(II) in river water, waste water and pond water, and the range of recovery was 96%-102%. This method is simple, rapid, sensitive, accurate, highly selective and suitable for automatic and continuous analysis.

[On-line determination of transitional metal ions by low-pressure ion chromatography with chemiluminescence detection].

The separation and determination of five transitional metal ions, Co2+, Cu2+, Mn2+, Fe2+ and Cr3+ by low-pressure ion chromatography with chemiluminescence detection were investigated for the first time. The separation was carried out on a C3 ion chromatographic column by using a step gradient elution with the mobile phase of oxalic acid-citric acid solution. The five transitional metal ions could be separated simultaneously. Luminol-H2O2-Mn+ system was used as the flow injection chemiluminescence analytical system. Under the optimum conditions with 0.5 mmol.L-1 luminol, 0.05 mol.L-1 H2O2 and 0.020 mol.L-1 NaOH, the linear ranges (mg.L-1) for Co2+, Cu2+, Mn2+, Fe2+ and Cr3+ were 0.001-0.1, 0.1-6, 0.06-4, 0.03-5 and 0.025-1 respectively; the detection limit (microgram.L-1) for Co2+, Cu2+, Mn2+, Fe2+ and Cr3+ were 0.85, 85, 42, 21 and 20. The present method is simple, rapid, accurate and has been successfully applied to detect Co2+ in vitamin B12 and Co2+, Cu2+, Mn2+, Fe2+ and Cr3+ in human hair sample with satisfactory results, which were in good agreement with those from atomic absorption spectrometry.