Nebulized flame ionization detection in high performance liquid chromatography

A nebulized flame ionization detector interfaced with LC was examined and found to be more versatile in applications than common LC detectors, such as UV, RID, ELSD and CAD. The technique can be used for both volatile and non-volatile analytes. It is compatible with gradient elution and can be used for the analysis of non chromophore-possessing analytes. The calibration plots of non-volatile analytes were linear in contrast to other aerosol-based detectors, such as ELSD and CAD. The technique was examined in three consecutive stages; optimization of the FID, testing the response patterns of analytes (volatile and non-volatile) and applications to the analysis of compounds of diverse functional groups. The optimum conditions for the operation of the FID were: hydrogen, 157 ml/min; nitrogen, 250 ml/min; air, 654 ml/min; spray chamber internal diameter, 40 mm, collector internal diameter, 4mm and eluent (water), 1 ml/min. The calibration plots of all volatile analytes were linear while those of the non-volatile analytes were linear only when anions (in the form of sulfuric acid, nitric acid, hydrochloric acid, orthophosphoric acid, sodium sulphate and ammonium sulphate) were added to the eluent The separations of diverse analytes (alcohols, aldehydes, ketones, amines, amino acids, carboxylic acids and sugars) gave detection limits in the low μg range

Equilibrium Sorption Studies of Hg (II) Ions from Aqueous Solution using Powdered Swamp Arum (Lasimorpha senegalensis) Seeds

The potential of swamp arum (Lasimorpha senegalensis) seeds as a low-cost adsorbent for the removal of  Hg (II) ions from aqueous solution was investigated in this study. The influence of initial metal  concentration on the percent adsorption of Hg (II) ions onto powdered swamp arum seeds was studied in a batch system and the filtrate was analyzed using Atomic Absorption Spectrometry (AAS). The percent adsorbed for 10, 20, 40, 60 and 80 mg/L of the aqueous solution were 97.7, 98.9, 99.3, 99.7, and 96.5% respectively. Three isotherms; Langmuir, Freundlich, and BET were used to model the equilibrium sorption of Hg (II) ions onto powdered swamp arum seeds, with a correlation coefficient of 0.998, 0.784 and0.842 respectively. The Langmuir model fitted the equilibrium data best, with a correlation coefficient of 0.998 and a maximum adsorption capacity qm, of 5.917 mg/g. Thus, indicating monolayer coverage on the adsorbent. The results showed that swamp arum seed have the potential to be applied as alternative lowcost biosorbent in the remediation of heavy metal contamination in waste water. ©JASEMKeywords: Equilibrium, sorption studies, ions, solution, swamp arum, seeds

Liquid chromatography–flame ionisation detection using a nebuliser/spray chamber interface. Part 1. Design and testing

AbstractA nebuliser and spray chamber have been used to link a flow injection analyser to a flame ionisation detector, with the potential for the combination to be used as a universal detector for liquid chromatography. The hydrogen and air flows were adjusted to achieve a stable system. The detector responded to both volatile and involatile analytes and to compounds with and without chromophores, including alkanes, alkanols, aromatic amides and acids, phenols, amino-acids and carbohydrates and gave a linear response for many analytes. However, for involatile polar analytes it was necessary to add traces of acid or salt to the carrier stream to obtain a linear response