• Bulletin of the Korean Chemical Society
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• v.32 no.11
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• pp.3923-3927
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• 2011

A noble method for pre-concentration and speciation of ultra trace As (III) and As (V) in urine and whole blood samples based on dispersive liquid-liquid microextraction (DLLME) has been developed. In this method, As (III) was complexed with ammonium pyrrolidine dithiocarbamate at pH = 4 and Then, As (III) was extracted into the ionic liquid (IL). Finally, As (III) was back-extracted from the IL with hydrochloric acid (HCl) and its concentration was determined by flow injection coupled with hydride generation atomic absorption spectrometry (FI-HGAAS). Total amount of arsenic was determined by reducing As (V) to As (III) with potassium iodide (KI) and ascorbic acid in HCl solution and then, As (V) was calculated by the subtracting the total arsenic and As (III) content. Under the optimum conditions, for 5-15 mL of blood and urine samples, the detection limit ($3{\sigma}$) and linear range were achieved 5 ng $L^{-1}$ and 0.02-10 ${\mu}g\;L^{-1}$, respectively. The method was applied successfully to the speciation and determination of As (III) and As (V) in biological samples of multiple sclerosis patients with suitable precision results (RSD < 5%). Validation of the methodology was performed by the standard reference material (CRM).

• Analytical Science and Technology
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• v.34 no.4
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• pp.180-190
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• 2021

This study compared the efficacy of chiral GC and chiral HPLC for the analysis of nicotine. To develop a suitable dispersive liquid-liquid microextraction (DLLME) method, the following parameters were optimized: pH, extraction solvent, dispersive solvent, type and quantity of salt, and laboratory temperature. The validation of the method was carried out by the established HPLC method. The LODs were 0.11 ㎍/mL and 0.17 ㎍/mL for the (S)- and (R)- enantiomers, respectively. The LOQs were 0.30 ㎍/mL and 0.44 ㎍/mL, respectively. The optimal calibration range was between 0.30-18 ㎍/mL and 0.44-4.40 ㎍/mL, respectively, and the correlation coefficient (r²) was 0.9978-0.9996. The intra-day accuracy was 79.9-110.6 %, and the intra-day precision was 1.3-12.0 %. The inter-day accuracy was 87.8-108.0 %, and the inter-day precision was 4.0-12.8 %. E-liquid and biological fluids (urine and saliva) were analyzed using the established method.

• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.829-835
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• 2011

A dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFO) has been developed as a new approach for the extraction of trace copper in water and beverage samples followed by the determination with flame atomic absorption spectrometry. In the DLLME-SFO, 8-hydroxy quinoline, 1-dodecanol, and methanol were used as chelating agent, extraction solvent and dispersive solvent, respectively. The experimental parameters related to the DLLME-SFO such as the type and volume of the extraction and dispersive solvent, extraction time, sample volume, the concentration of chelating agent and salt addition were investigated and optimized. Under the optimum conditions, the enrichment factor for copper was 122. The method was linear in the range from 0.5 to $300\;ng\;mL^{-1}$ of copper in the samples with a correlation coefficient (r) of 0.9996 and a limit of detection of $0.1\;ng\;mL^{-1}$. The method was applied to the determination of copper in water and beverage samples. The recoveries for the spiked water and beverage samples at the copper concentration levels of 5.0 and $10.0\;ng\;mL^{-1}$ were in the range between 92.0% and 108.0%. The relative standard deviations (RSD) varied from 3.0% to 5.6%.