Quenching-Chemiluminescence Determination of Trace Amounts of l-Tyrosine Contained in Dietary Supplement by Chemiluminescence Reaction of an Iron-Phthalocyanine Complex

The chemiluminescence (CL) signal immediately appeared when a hydrogen peroxide solution was injected into an iron-phthalocyanine tetrasulfonic acid (Fe-PTS) aqueous solution. Moreover, the CL intensity of Fe-PTS decreased by adding l-tyrosine. Based on these results, the determination of trace amounts of l-tyrosine was developed using the quenching-chemiluminescence. The calibration curve of l-tyrosine was obtained in the concentration range of 2.0 × 10−7 M to 2.0 × 10−5 M. Moreover, the relative standard deviation (RSD) was 1.63 % (n = 5) for 2.0 × 10−6 M l-tyrosine, and its detection limits (3σ) were 1.81 × 10−7 M. The spike and recovery experiments for l-tyrosine were performed using a soft drink. Furthermore, the determination of l-tyrosine was applied to supplements containing various kinds of amino acids. Each satisfactory relative recovery was obtained at 98 to 102%

Fluorescence Detection-FIA for ppb Levels of Bromate with Trifluoperazine

Abstract The fluorescence of tifluoperazine at EX:300 nm and EM:485 nm was changed into non-fluorescent substance in the presence of bromate under acidic conditions, and the fluorescence detection-FIA of trace amounts of the bromate was developed using this phenomenon. In the concentration range of 1-15 μg L -1 , the bromate analysis was able to obtain a good straight line and eighteen samples per hour were measured. For 7.5 μg L -1 of bromate, the relative standard deviation(RSD) was 2.03 %(n=5) and the detection limit (3σ) was 1.47 μg L -1

Separation and Recycling for Rare Earth Elements by Homogeneous Liquid-Liquid Extraction (HoLLE) Using a pH-Responsive Fluorine-Based Surfactant

A selective separation and recycling system for metal ions was developed by homogeneous liquid-liquid extraction (HoLLE) using a fluorosurfactant. Sixty-two different elemental ions (e.g., Ag, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, In, Ir, La, Lu, Mg, Mn, Mo, Nb, Nd, Ni, Os, P, Pb, Pd, Pr, Pt, Re, Rh, Ru, Sb, Sc, Se, Si, Sm, Sn, Sr, Ta, Tb, Te, Ti, Tl, Tm, V, W, Y, Yb, Zn, and Zr) were examined. By changing pH from a neutral or alkaline solution (pH ≥ 6.5) to that of an acidic solution (pH < 4.0), gallium, zirconium, palladium, silver, platinum, and rare earth elements were extracted at >90% efficiency into a sedimented Zonyl FSA® (CF3(CF2)n(CH2)2S(CH2)2COOH, n = 6–8) liquid phase. Moreover, all rare earth elements were obtained with superior extraction and stripping percentages. In the recycling of rare earth elements, the sedimented phase was maintained using a filter along with a mixed solution of THF and 1 M sodium hydroxide aqueous solution. The Zonyl FSA® was filtrated and the rare earth elements were recovered on the filter as a hydroxide. Furthermore, the filtrated Zonyl FSA was reusable by conditioning the subject pH