Harvey Diehl

Bio: Harvey Diehl is an academic researcher from Iowa State University. The author has contributed to research in topics: Perchloric acid & Titration. The author has an hindex of 23, co-authored 88 publications receiving 2261 citations.

The Versenate Titration for Total Hardness

Abstract: ersity of Zurich has reported in Helvetica Chimica Acta for 1947 and 1948 the results of a brilliant series of investigations of the complex ions of the alkaline-earth and other metals with aminopolycarboxylic acids. Iminotriacetic acid, ethylenediaminetetraacetic acid and other aminopolycarboxylic acids form very slightly ionized compounds with the alkaline earths, and the formation of these materials can be employed for the determination of calcium, magnesium and various bivalent metals. The problem of determining the endpoint in this titration was solved by Biedermann and Schwarzenbach ( 1 ) in an unusual manner, using a dye which also has the property of forming slightly ionized compounds with magnesium and calcium. For the determination of the total hardness of water (calcium plus magnesium) the method is superior to the soap method in accuracy and speed and is equal in accuracy to the timeconsuming soda-reagent method.

Ferrozine---a new spectrophotometric reagent for iron

Abstract: -N=C&N-, have been known to react as bidentate ligands with certain metal ions such as ferrous, cuprous, and cobaltous, to give colored complex species (1-6). This effect was first noticed with the ferrous ion ( I ) , and since this complex of a given compound is generally of a more intense color than are those with other ions (7), the atomic configuration in question was given the trivial name of the ferroin group. During the last century, hundreds of compounds containing the ferroin group have been synthesized (7), the majority of which demonstrate the ability to form complexes with the ferrous ion. Most of these complexes are only weakly colored, are unstable under normal physical conditions, or are formed over a very narrow pH range. A few of these compounds, however, form stable, intensely colored species with the ferrous ion and are, therefore, suitable for the quantitative determination of iron (8). Examples of compounds which have found acceptance for such use are 1,lOphenanthroline (9), 4,7-diphenyl-l,lO-phenanthroline (IO), 2,2‘-bipyridine (I]), 2,6-bis(2-pyridyl)-pyridine (11). 2,4,6tris(2-pyridyl)-1,3,5-triazine (12), and phenyl 2-pyridyl ketoxime (13, 14). Many of these reagents are the product of difficult and tedious organic syntheses and, hence, are high in cost (14). Although for even the most expensive of these reagents, the cost of a single manual analysis is fairly low, when one considers automated continuous instrumental analysis, a lowcost yet highly sensitive reagent would be desirable, since the cost of maintaining such an analytical instrument with I

Loop-mediated isothermal amplification (LAMP) of gene sequences and simple visual detection of products

Abstract: As the human genome is decoded and its involvement in diseases is being revealed through postgenome research, increased adoption of genetic testing is expected. Critical to such testing methods is the ease of implementation and comprehensible presentation of amplification results. Loop-mediated isothermal amplification (LAMP) is a simple, rapid, specific and cost-effective nucleic acid amplification method when compared to PCR, nucleic acid sequence-based amplification, self-sustained sequence replication and strand displacement amplification. This protocol details an improved simple visual detection system for the results of the LAMP reaction. In LAMP, a large amount of DNA is synthesized, yielding a large pyrophosphate ion by-product. Pyrophosphate ion combines with divalent metallic ion to form an insoluble salt. Adding manganous ion and calcein, a fluorescent metal indicator, to the reaction solution allows a visualization of substantial alteration of the fluorescence during the one-step amplification reaction, which takes 30-60 min. As the signal recognition is highly sensitive, this system enables visual discrimination of results without costly specialized equipment. This detection method should be helpful in basic research on medicine and pharmacy, environmental hygiene, point-of-care testing and more.

The Aβ Peptide of Alzheimer's Disease Directly Produces Hydrogen Peroxide through Metal Ion Reduction†

Abstract: Oxidative stress markers characterize the neuropathology both of Alzheimer's disease and of amyloid-bearing transgenic mice. The neurotoxicity of amyloid Aβ peptides has been linked to peroxide gen...