developed methods DLLME
1)Single-drop microextraction (SDME)
2)Hollow fiber liquid phase microextraction (HF- LPME)
3) Dispersive liquid- liquid phase microextraction (DLLME)
Single-drop microextraction
advantages
Low cost
negligible volume of solvents
Less toxic
The small sample
disadvantage
Drop
Formation of air bubbles
Hollow fiber liquid phase microextraction
advanteges
Allowing rapid stirring
Negligible volume of solvents
EXcellent sample cleanup
High enrichment factor
Solvent Stability
Temperature stability
Possibility of taking samples in long time
disadvantage
Memory effect
DLLME
Phase Extractor
Disperser solvent
Aqueous phase
Disperive liquid-liquid microextraction
Factors affecting the extraction recovery
Volume and type of solvent extraction
Volume and type of disperser solvent
Effect of ionic strength
Sample volume
Extraction time
advanteges
Simplicity
Rapid
Cheap price
High recovery
High enrichment factor
Comparison of DLLME with other methods
The key point of this method is the short
time of extraction.
Disadvantage in DLLME
Very toxic solvents
Incompatibility
Frequency of papers published in the period mid-2010 to mid-2012 for the major solvent microextraction
LDS-DLLME
advantages
Less toxic solvents
Most of the solvent
compatibility with HPLC
AA-DLLME
advantages
Less toxic solvents
compatibility with HPLC
ST-DLLME
Characteristics
The new process for phase separation does not require centrifugation
This method can be used only with low-density extraction solvent.
DLLME-SFO
Characteristics
Extraction solvent
Low volatility, toxicity, Solubility
Its peak in the chromatogram should be well separated from the peak analytes
Melting point close to room temperature
Microwave
درست شود.
The key point
Just adjust the power
UA-DLLME
disadvantage
Ultrasonic irradiation can lead to the formation of stable emulsions.
It is often hard to uniform ultrasonic energy between natural and experimental samples was assured.
VA-DLLME
Advantage
Using Vertex economically more efficient than ultrasonic.
There dispersion under stirring vortex is thermodynamically unstable.
Characteristics
Hydrophobic
Hydrophilic
Reduce the surface tension
SA-DLLME
Cold-induced aggregation microextraction
Influence of anti-sticking agent
Applications of DLLME
GC, HPLC, AAS, and UV–Vis spectrophotometry
Conclusions:
Advantages of DLLME include
Simplicity of operation
Rapidity
Low cost
High recovery
High enrichment factor
And environmental benignity
Organic and inorganic compounds
Refrence:
[1] M.A. Jeannot, F.F. Cantwell ,Anal. Chem., 1997, 69 (2), pp 235–239.
[2] S. Pedersen-Bjegaard, K.E. Rasmussen, Anal. Chem. 71 (1999) 2650–2656.
[3] H. Jiang, B. Hu, B. Chen, W. Zu, . Spectrochimica Acta Part B 63 (2008) 770–776.
[4] M. Rezaee, Y. Assadi, M.-R. Milani Hosseini, E. Aghaee, F. Ahmadi, S. Berijani, J. Chromatogr. A 1116 (2006) 1–9.
[5] F. Pena-Pereir, I. Lavill, C. Bendicho, Spectrochimica Acta Part B 64 (2009) 1–15.
[6] M. Rezaee, Y. Assadi, M.R. Milani osseini, E. Aghaee, F. Ahmadi, S.Berijani, Journal of Chromatography A, 1116 (2006) 1–9. Cold-induced aggregation microextraction
[7] M.A. Farajzadeh, S.E. Seyedi, M.S. Shalamzari, M. Bamorowat, J. Sep. Sci. 32 (2009) 3191.
[8] Y. Zhang, H. Kee Lee, Journal of Chromatography A, 1274 (2013) 28– 35.
[9] M. R.Hadjmohammadi, M. H. FatemiP. Shakeri, J. Sep. Sci.35(2012) 3375–3380.
[10] H.Chen, R.Chen, S.Li, J. of Chromatogr.y A, 1217 (2010) 1244–1248.
[11] M.I. Leong, S.D. Huang, , J. Chromatogr. A 1211(2008) 8–12.
[12] N.Campillo, P.Vinas, N. Martnez-Castillo, M. Hernndez-Cَrdoba, J. of Chromatogr. A, 1218 (2011) 1815–1821.
[13] J. Regueiro, M. Llompart, C. Garcia-Jares, J.C. Garcia-Monteagudo, R. Cela, J. Chromatogr. A 1190 (2008) 27.
[14] Y. Zhang, H. Kee Lee, Journal of Chromatography A, 1249 (2012) 25– 31
[15] M. Moradi, Y. Yamini∗, A. Esrafili, S. Seidi, Talanta 82 (2010) 1864–1869.
[16] F. Pena-Pereir, I. Lavill, C. Bendicho, , Spectrochimica Acta Part B 64 (2009) 1–15.
[17] M. Baghdadi, F. Shemirani,: analytica chimica acta 613 (2008) 56–63.
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