Ultrasensitive determination of mercury in human saliva by atomic fluorescence spectrometry based on solidified floating organic drop microextraction

Abstract

We report on a new, rapid and simple method for the determination of ultra-trace quantities of mercury ion in human saliva. It is based on solidified floating organic drop microextraction and detection by cold vapor atomic fluorescence spectrometry (CV-AFS). Mercury ion was complexed with diethyldithiocarbamate, and the hydrophobic complex was then extracted into fine droplets of 1-undecanol. By cooling in an ice bath after extraction, the droplets in solution solidify to form a single ball floating on the surface of solution. The solidified microdrop containing the mercury complex was then transferred for determination by CV-AFS. The effects of pH value, concentration of chelating reagent, quantity of 1-undecanol, sample volume, equilibration temperature and time were investigated. Under the optimum conditions, the preconcentration of a 25-mL sample is accomplished with an enrichment factor of 182. The limit of detection (3σ) is 2.5 ng L −1 . The relative standard deviation for seven replicate determinations at 0.

Atomic spectrometry update. Clinical and biological materials, foods and beverages

“…This involved complexation of the Hg 2+ from 25 mL saliva with DDC followed by extraction into ne droplets of 1-undecanol which were cooled to solidify into a microdrop. 36 An enrichment factor of 182 was reported, giving an LOD of 2.5 ng L À1 . Variations around this general approach were used to determine the concentrations of As in blood and urine by HG-AAS 37 with LODs of 5 ng L À1 and 0.02-10 mg L À1 , respectively, and Se species in garlic by ETAAS 38 for which the LOD was 15 ng L À1 .…”

“…The method was validated by analysing DORM-2 CRM. A very novel sample preparation method was described by Yuan et al 36 for the quantitative determination of Hg in human saliva by AFS. Mercury was complexed with DDC and extracted into ne droplets of 1-undecanol.…”

Trace Determination of Hg(II) in Human Saliva Using Disposable Electrochemically Pretreated Graphite Pencil Electrode Surfaces

“…15,16 Various methods have been developed recently to determine mercury in body fluids, including urine, 17 serum, 18 and saliva. 19,20 Trace levels of mercury can be measured by techniques including atomic absorption spectros-copy, 21 cold vapor atomic emission, 22 X-ray fluorescence, 23 mass spectrometry, 24 and ICP-OES. 25 However, all of these methods have limitations in the routine analysis of mercury, including high costs, complex instrumentation, long duration and poor selectivity.…”

Application of Preconcentration and Separation Techniques in Atomic Fluorescence Spectrometry

“…The liquid drop floating on the surface of the aqueous solution is changed into a solid ball very fast in an ice bath, which can easily be transferred into a conical vial for dissolution and analysis. Wang et al(27) and Yuan et al(28) applied this method for the determination of selenium and mercury in water and human saliva samples by AFS. The target analytes were firstly complexed with a proper ligand and then extracted into solidified floating drops of 1-undecanol.…”