Quantification of basicity

Puopolo PR, VolpiceHi SA, Johnson DM, Flood JG. Emergency toxicology testing (detection, confirmation, and quantification) of basic drugs in serum by liquid chromatography with photodiode array detection. Clin Chem 1991 37 2124-30. 

In this book, a simpler approach to these central quantities— in addition to energy—is proposed for the first-year students. The quantities are characterized by their typical and easily observable properties, i.e., by creating a kind of wanted poster for them. This phenomenological description is supported by a direct measuring procedure, a method which has been common practice for the quantification of basic concepts such as length, time, or mass for a long time. 

Thunig J, Flo L, Pedersen-Bjergaard S, Hansen SH, Janfelt C. Liquid-phase microextraction and desorption electrospray ionization mass spectrometry for identification and quantification of basic drugs in human urine. Rapid Commun Mass Spectrom 2012 26 133-140. 

The basic premise of this method is that the magnitude of the detector output, as measured by hj for a particular fraction, is proportional to the weight of that component in the sample. In this sense the chromatogram itself presents a kind of picture of the molecular weight distribution. The following column entries provide additional quantification of this distribution, however. 

Fluorescence Immunoassay. Basic FIA follows the same formats and approaches as EIA. The difference Hes in the indicator a fluotophote is used instead of an enzyme. This allows direct quantification of the indicatot—antibody—antigen complex, or free indicator-reagent, without the need for a substrate. 

Since one of the main chemical and technological problems of conducting polymers is their low stability for long-term applications, and since storage capacity is a quantification of the basic property of these... 

A polyethylene-coated (PEE) silica column was used with water-methanol eluents to achieve the separation and retention of 27 pesticides.40 The retention times of 33 commercial pesticides were determined on an octadecyl (ODS)-derivatized alumina column using water-methanol eluents and compared with retention properties on an ODS-silica column packing.41 More recently, RP-HPLC was used in combination with diode array detection for the identification and quantification of 77 pesticides (acidic, basic, and neutral) in groundwater samples.42... 

Identification of dyes on dyed textiles is traditionally carried out by destructive techniques [493], TLC is an outstanding technique for identification of extracted dyestuffs and examination of inks. Figure 4.9 shows HPTLC/SERRS analysis of acridine orange [492], Wright et al. [494] have described a simple and rapid TLC-videodensitometric method for in situ quantification of lower halogenated subsidiary colours (LHSC) in multiple dye samples. The results obtained by this method were compared with those obtained by an indirect TLC-spectrophotometric method and those from HPLC. The total time for the TLC-videodensitometric assay of five standards and four samples applied to each plate was less than 45 min. The method is applicable for use in routine batch-certification analysis. Loger et al. [495,496] have chromatographed 19 basic dyes for PAN fibres on alumina on thin-layer with ethanol-water (5 2) and another 11 dyes on silica gel G with pyridine-water... 

For quantitative analysis of protein concentration the colorimetric Bradford-assay [147] is most commonly used. Here another Coomassie dye, Brilliant Blue G-250, binds in acidic solutions to basic and aromatic side chains of proteins. Binding is detected via a shift in the absorption maximum of the dye from 465 nm to 595 nm. Mostly calibration is performed with standard proteins like bovine serum albumin (BSA). Due to the varying contents of basic and aromatic side chains in proteins, systematic errors in the quantification of proteins may occur. 

The aromaticity of five-membered rings with two or more heteroatoms was discussed in detail in earlier reviews.52 100 111 In a comprehensive survey on the quantitative measurements of aromaticity,112 it has been shown that basicity-based quantification of aromaticity gave more reproducible resonance energies than other methods, such as heats of formation, ring currents, magnetic susceptibilities, and theoretical indices. 

Fluorescence-based assays either in the measurement of enzyme activity or in the quantification of enantioselectivity all have a high degree of sensitivity, which allows the use of very dilute substrate concentrations and extremely small amounts of enzymes. Basically, there are two different approaches. One involves the use of a substrate of interest to which a fluorescent-active (or potentially active) moiety is covalently attached. The second approach makes use of a fluorescence-based sensor, which gives rise to a signal as a consequence of the enzyme-catalyzed reaction of a substrate of interest. 

The quantification of the formulation of SOW systems was studied in detail during the 1970 s when a considerable research drive was dedicated to enhanced oil recovery by surfactant flooding methods [2], The basic concepts came from Winsor s work on the phase behavior of SOW systems and its R ratio of interactions between the surfactant molecules adsorbed at interface and oil and water [3], which has been presented thoroughly in a review book [4]. 

Native urine should be protected from light and stored at -20°C until processed. Oxidized urine sample can be stored at room temperature, but light protection is still recommended. Two procedures for the oxidation of urine (and other samples) are used (1) oxidation with manganese dioxide (Mn02) under acidic conditions, and (2) oxidation with iodine (iodine/potassium iodide, I2/KI) under acidic and basic conditions. The Mn02 oxidation method is a routine method used to quantify total pterins (fully oxidized neopterin, monapterin, biopterin, primapterin, isoxanthopterin, and pterin) the I2/KI method is used according to Fukushima and Nixon [11] for the differential oxidation of pterins and quantification of BH4. Total biopterin represents the sum of BH4, BH2, and fully oxidized biopterin. Under acidic conditions BH4 and BH2 are oxidized to biopterin, while under basic conditions only BH2 is oxidized to... 

In the Basic Protocol, gas-liquid chromatography (GLC) using an open tubular wall, coated, fused silica column with nonpolar liquid phase is described. In Alternate Protocol 1, reversed-phase HPLC (RP-HPLC) is applied for separation and quantification of cholesterol. In Alternate Protocol 2, enzymatic measurement is applied for determination of cholesterol. 

Currently, high-performance liquid chromatography (HPLC) methods have been widely used in the analysis of tocopherols and tocotrienols in food and nutrition areas. Each form of tocopherol and tocotrienol can be separated and quantified individually using HPLC with either a UV or fluorescence detector. The interferences are largely reduced after separation by HPLC. Therefore, the sensitivity and specificity of HPLC methods are much higher than those obtained with the colorimetric, polarimetric, and GC methods. Also, sample preparation in the HPLC methods is simpler and more efficiently duplicated than in the older methods. Many HPLC methods for the quantification of tocopherols and tocotrienols in various foods and biological samples have been reported. Method number 992.03 of the AOAC International Official Methods of Analysis provides an HPLC method to determine vitamin E in milk-based infant formula. It could probably be said that HPLC methods have become dominant in the analysis of tocopherols and tocotrienols. Therefore, the analytical protocols for tocopherols and tocotrienols in this unit are focused on HPLC methods. Normal and reversed-phase HPLC methods are discussed in the separation and quantification of tocopherols and tocotrienols (see Basic Protocol). Sample... 

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