Indicator colorimetric reagent

Diphenylcarbazide as adsorption indicator, 358 as colorimetric reagent, 687 Diphenylthiocarbazone see Dithizone Direct reading emission spectrometer 775 Dispensers (liquid) 84 Displacement titrations 278 borate ion with a strong acid, 278 carbonate ion with a strong acid, 278 choice of indicators for, 279, 280 Dissociation (ionisation) constant 23, 31 calculations involving, 34 D. of for a complex ion, (v) 602 for an indicator, (s) 718 of polyprotic acids, 33 values for acids and bases in water, (T) 832 true or thermodynamic, 23 Distribution coefficient 162, 195 and per cent extraction, 165 Distribution ratio 162 Dithiol 693, 695, 697 Dithizone 171, 178... 

V. Treatment with Diphenylamine Reagent. See item E under colorimetric reagents and Charts A Si B. A yel color indicates the presence of one of the expls TNT, TNAns, HNDPhA, PA, AmmPic or DNPh viol, blue or black color indicates DNT, DNB, DINA, Tetryl, PETN, RDX, EDNA, EDD or AN red color indicates o-MNN... 

Reagents, Indicators, and Solutions. This section includes the specifications and testing methods for reagents to be used in the tests specified in the USP-NF, and directions for making the various indicator, buffer, colorimetric, test, and volumetric solutions used in the testing. Reagents for which ACS specifications exist are referenced to the ACS book (7). 

The other method is less accurate but more rapid and involves direct Nessleri2ation of the sample for colorimetric deterrnination. Other colorimetric indicators with more sensitivity, such as indophenol, have been used in place of Nessler s reagent. Ion-selective electrodes have also found use in analysis for trace ammonia (93). 

It is certainly clear that a coulometric titration, like any other type of titration, needs an end-point detection system in principle any detection method that chemically fits in can be used, be it electrometric, colorimetric, photoabsorptionmetric, etc. for instance, in a few cases the colour change of the reagent generated (e.g., I2) may be observed visually, or after the addition of a redox, metal or pH indicator the titration end-point can be detected photoabsorptiometrically by means of a light source and photocell combination. Concerning the aforementioned coulometric titration of Fe(II), it is... 

The colorimetric reaction of urea nitrate with p-DMAC [91] was also adopted as a field test, UN-1. The reagent (0.4% in ethanolic solution) is sprayed on the sample, or on the suspected area, and the appearance of a red color within 1 min indicates the presence of urea nitrate [103]. 

All integrated sensors based on an interaction between the analyte and reagent (neither of which is used in a retained form) and regeneration of the latter rely on chemiluminescent reactions involving electroregeneration of the reagent or a quenching phenomenon. On the other hand, absorptiometric and reflectometric sensors of this type use colorimetric acid-base indicators supported on a suitable material. 

SafTest System A set of kits for colorimetric determination of various oxidation indices (POV, ACV, MDA, HNE) with undisclosed reagents . ... 

A concise survey regarding very specific reagents based on heterocyclic-sub-stituted formazans is compiled in [75], The cyclic formazans 47 are lithium-specific indicator dyes, useful for the quantitative colorimetric determination of lithium ions in biological fluids such as blood [76],... 

In coulometric analyzers, S02 serves to reduce a solution of bromine or iodine. These elements can then be detected to give an indication of the S02 content of the sample air stream. The required supply of reagents for coulometric analyzers is usually less than the reagent requirements of either colorimetric or conductiometric analyzers. 

The Merck Company of Darmstadt, Germany developed the OXIFRIT FRIT-EST to measure oil quality in frying operations, especially in restaurants. The Fritest measures the alkali color number to indicate oxidized fatty acid (OFA) and the Oxifrit Test measures oxidation products in the fryer oil. Both tests are colorimetric and use a solvent-based reagent system. The test methodology is too comphcated for the restaurant personnel. 

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