What is Limiting Reagents?
Reagents have been used to target a wide group of functionalities, including ketones (using p-nitrobenzene diazonium fluoroborate as the diazo reagent),159 hydroxyl groups, as in 1-hydroxy-2-imidazol-1-yl-phosphonoethyl phosphoric acid (zoledronic acid), in urine and blood samples (using trimethylsilyl diazomethane under multiple methyl ester formation),160 the antidepressant reboxetine (RBX) in human plasma (using 7-flouro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-F) reagent),130 isomeric separation of fatty acids from lipids (using methylation with diazomethane in diethyl ether),161 and for amines, e.g., erythromycyclamine (using 7-chloro-4-nitro-benzo-2-oxa-1,3-diazole (NBD-Cl)).

Extraction Techniques and Applications: Food and Beverage
G. Dugo, ... M. Saitta, in Comprehensive Sampling and Sample Preparation, 2012
4.22.6 Purity of the Reagents
The reagents for analytical use are commercially available in varying degrees of purity: for the analysis of trace elements, it is appropriate that they are of the highest possible degree of purity; pure reagents for the analysis of trace elements are controlled from the manufacturer and the main impurities detected and their relative amounts are listed on the container. It is therefore essential, not only that the impurities are present in the least possible amount but also that it is such as to avoid influencing the outcome of analysis. Even high-purity grade reagents can be a source of contamination, especially when working at very low concentration levels, and it may be necessary to test those that are used for impurities; when impurities are detected in reagents such as nitric or perchloric acid, it should be better to distil them in a quartz distiller before use. It is essential that the water used to dilute the samples is of the highest purity too: it must have a very low conductivity and should be checked constantly; when the de-ionized water used is not suitable, it can be prepared from the de-ionized water by double distillation in a quartz distiller.1–3
Synthesis and Biochemical Evaluation of Fluorinated Monoamine Oxidase Inhibitors
Kenneth L. Kirk, ... Günter Haufe, in Fluorine and Health, 2008
3.4 Allyl hydrazines as SSAO inhibitors
Carbonyl reagents, such as semicarbazide and phenelzine (27), are inactivators of SSAO. In a strategy that includes two inactivating structural motifs (allylamine and hydrazine), a series of allyl hydrazines including the series 28a–c as well as the fluoroallyl analogue 29 were prepared. Compounds 28ac were potent irreversible inhibitors of SSAO, and compounds 28a,c had particularly good selectivity with respect to MAO inhibition. The presence of the vinyl fluoride in 29 had little effect on potency but did result in a loss in selectivity [82].
K. Buchtela, in Encyclopedia of Analytical Science (Second Edition), 2005
Radio Reagent Method
In radio reagent methods a radioactive species is used in a quantitative reaction and the change in activity of that species in the course of the reaction is measured. The radioactive species may be a labeled reagent or the analyte.
After separation from excess reagent by any suitable chemical separation method like liquid–liquid distribution, chromatography, etc., the mass or concentration of this product is determined from activity measurement.
The advantage of radio reagent methods over classical analytical techniques arises from the high sensitivity of the activity measurements that are not subject to interference by other substances. The principle of the radio reagent method can be adapted to various procedures.
What is Limiting Reagents?
The reactant that is entirely used up in a reaction is called as limiting reagent.
Limiting reagents are the substances that are completely consumed in the completion of a chemical reaction. They are also referred to as limiting agents or limiting reactants. According to the stoichiometry of chemical reactions, a fixed amount of reactants is required for the completion of the reaction. Let us consider the following reaction of formation of ammonia:
3H2 + N2 → 2NH3
In the reaction given above, 3 moles of Hydrogen gas are required to react with 1 mole of nitrogen gas to form 2 moles of ammonia. But what if, during the reaction, only 2 moles of hydrogen gas are available along with 1 mole of nitrogen.
In that case, the entire quantity of nitrogen cannot be used (because the entirety of nitrogen requires 3 moles of hydrogen gas to react). Hence, the hydrogen gas is limiting the reaction and is therefore called the limiting reagent for this reaction.