BRIEFS Mediated, Thin-Layer Cell. Coulometric Determination of Monomolecular Films of Trichlorosilane Viologen Derivatives at Gold and Nonconducting Surfaces 754 The method is used to verify the monomolecular quantities of 7V-methyl-iV-(2-(trimethoxysilyl)ethyl)benzyl-4,4/-bipyridinium dichloride and of other viologen silane derivatives immobilized at gold electrodes. Cindra A. Widrig and Marcin Majda*, Department of Chemistry, University of California, Berkeley, Calif. 94720 Anal Chem., 59 (1987) Voltammetric-Amperometric Dual-Electrode Detection for Flow Injection Analysis and Liquid Chromatography 761
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The potential is scanned at the upstream electrode, and the reaction products are detected amperometrically at the downstream electrode. Detection limits of 10" 7 M hydroquinone are achieved at scan rates up to 2.0 V/s. Craig E. Lunte, Thomas H. Ridgway, and William R. Heineman*, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221 " Anal Chem., 59 (1987) 1,3-Bis(8-quinolyloxy)propane Derivatives as Neutral Carriers for Lithium Ion Selective Electrodes 766 The Li + selectivity is improved by modifying the chain structure of the carriers. The detection limit for Li + is ~ 5 X 10" 5 mol/dm 3 . Kazuhisa Hiratani*, Tatsuhiro Okada, and Hideki Sugihara, Industrial Products Research Institute, 1-1-4, Yatabe-machi Higashi, Tsukuba-gun, Ibaraki 305, Japan Anal Chem., 59 (1987)
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769
Histamine is determined in the 0.1-2000 ng/mL range in wine and canned tuna samples. The detection limits for the first- and second-derivative methods are 0.16 and 0.06 ng/ mL, respectively. Carmen Gutierrez, Soledad Rubio, Agustina Gomez-Hens, and Miguel Valcârcel*, Department of Analytical Chemistry, Faculty of Sciences, University of Cordoba, Cordoba, Spain Anal Chem., 59 (1987)
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Determination of Histamine by Derivative Synchronous Fluorescence Spectrometry
Micelle-Stabilized Room-Temperature Liquid Phosphorimetry of Metal Chelates and Its Application to Niobium Determination 774 Published since 1955, the annual LabGuide leads all others in advertising pages and in reader usage (22,000 references daily). It's the true one-stop buying source where most manufacturers say with their ads, "Here we are. Compare our products with those of our competitors." That's why in more than six out of ten purchases by the 277,000 users it serves, the LabGuide is consulted before the purchase is made.
370 A · ANALYTICAL CHEMISTRY, VOL. 59, NO. 5, MARCH 1, 1987
Several requirements necessary for observing analytical RTP are presented. The limit of detection is 4 ppb with an RSD of ±2%. Possible mechanisms for the micellar reactions are discussed. Alfredo Sanz-Medel*, Pedro Luis Martinez Garcia, and Marta Elena Diaz Garcia, Department of Analytical Chemistry, Faculty of Chemistry, University of Oviedo, Oviedo, Spain Anal Chem., 59 (1987)
