(a)    Completed

Fatty acids, amines and amino acids are of immense importance. Some fatty acids are known precursors of the biologically important prostaglandins. Some other aliphatic amines and polyamines which are odorous substances are known precursors of the carcinogenic and toxic N-nitrosoamine, while amino acid is the building blocks of proteins. The ability to monitor these groups of compound is very important and several techniques to detect or confirm their presence are needed. A number of analytical methods have been used for their analysis ranging from classical to instrumental methods. However, each of these methods has its limitation and its disadvantages. Classical methods of analysis have the disadvantage of low sensitivity of detection, non-selectivity and non-specificity. The limitation of the classical approach has been overcome by modern chromatographic techniques in particular gas chromatography and high performance liquid chromatography. Gas chromatographic determination of amines at low concentration is hampered by adsorption and decomposition, column ghosting phenomena, tailed elution peaks and low detector sensitivity. To different degrees, one or more of these problems are encountered in the analysis of carboxylic and aminos acids using any of the available chromatographic techniques.

             A general approach to these problems has been the preparation of suitable derivatives of the   

             analytes because derivatization can be used to improve the chromatographic behavior as well   

           as the sensitivity and specificity of detection. Most derivatization approaches in          

             chromatographic analysis has been the use of solution reagents, in which the derivatising   

             reagent is present in solution and mixed with a solution of substrate of interest (homogenous

             derivatisation). A major draw back of homogenous derivatisation is associated with the need  

             to remove excess of reagent because the reagent often has similar behavior to the derivatives    

             in terms of its response to the chromatographic detection. Therefore the response of the system  

             to their derivative may be swamped by that of the excess reagent. This problem of excess 

           reagent is one that could be conveniently overcome if derivatisation was done in a  

           heterogenous medium using solid-phase reagent.

             So, in my research work, I have successfully developed, prepared, and applied some solid-        

           phase reagents; made up of  resin-bound N- nitroso- benzylsulfonamide,resin bound  

           naphthalene methanol,resin bound bisulfate addition compound of  salicylaldehyde and 

             solution reagent comprising sodium benzoxazole-2-sulfonate for analytical derivatization of  

             some fatty acids (acetic-, valeric-,hexanoic-.Octanoic-,nonanoic-,capric- lauric-, palmitic 

acids) and some primary and secondary amines  (ethylamine,propylamine,butylamine,diethylamine, di-n propylamine and di n-butylamine).

           The work have been concluded and published (see papers 1,2,4,7,8,9,20,) 

           In Progress:

                       Development of bound reagent i.e.Solid-Phase reagent (S-P reagent) for hydroxyl

                       compounds in particular alcohol. Previous workers have employed solution reagents for   

                       chemical derivatisation of hydroxyl (alcohol) functional  group to produce fluorescent

                       derivatives. One of the frustrating disadvantages of this solution reagent is due to close 

                       similarity in the spectra of fluorescent characteristics of   the reagent and the derivatives

                       it forms with the alcohols.The inevitable presence of excess reagent in the reaction 

                       mixture,causes high background response and hence an inadequate detection limit for

                       the analyte.Introduction of steps to remove excess reagent often makes the method

                       more tedious and more prone to error.Therefore,in this study, S-P reagent for the 

                       hydroxy (alcohol) functional group is developed.The idea is based on the high reactivity  

                       of 2-pyridyl esters of thiocarboxylic acids with alcohol in the presence of silver ion  

                       (Ag⁺).An initial stage of this reaction was the preparation of 2-

                       mercaptobenzoxazole, followed by quarternisation of the heteocyclic nitrogen through 

                       alkylation;after which the S-P reagent was prepared merely by stirring with cationic ion

                       exchange resin.The reagent was applied in this form to derivatise alcohol to produce 

                       derivative that fluorensced intensely.This study has become very important because it

                       offers the opportunity to develop new method for trace analysis of some Endocrine 

                       Disrupting Compounds (ECDs) like bisphenol A, triclosan and phthalates in clinical 

                       and environmental samples. Results of the study are beenprocessed for publication. My 

                       research work also continues with analysis of heavy metals and newly emerging  

                       environmental contaminant like poly brominate diphenyl ethers using both                       

                       concentrated-based approach and risk-based approach. Some publication arising from 

                       this work are highlighted in papers15,17,18,19,22,23,24,31,36,37,38,39,40 and 46.

                        (c)        Dissertation and Thesis:

                              (i)  Adewuyi, G.O. (1994) Development of resin bound reagents for analysis of 

                                   amines and carboxyilic acids.

                       M.Phil.Dissertation,University of Ibadan.

                                       (ii)  Adewuyi, G.O. (1997) Development of resin bound (or solid - phase) reagents  

                      for some different functionalities of   analytical importance.

                                   Ph.D.Thesis,University of Ibadan.