Method for determining concentrated form of analyte and method for converting concentrated form of analyte

1. A method of determining whether a preconcentrated analyte is stacked at a certain position in a material preconcentration device, the method comprising:

(a) establishing a critical mobility model that determines whether a mechanism for advection or electro-migration is dominant during preconcentration of the analyte in the device based on a comparison of an absolute value of an electrophoretic mobility of the analyte with a critical mobility of the analyte;

(b) calculating a critical mobility of the analyte by applying a parameter value to the critical mobility model, wherein the parameter value comprises an operating condition of the material preconcentration device; and

(c) inputting an analyte to the material preconcentration device; and

(d) operating the material preconcentration device to preconcentrate the analyte; and

(e) determining that the preconcentrated analyte is stacked at a certain position in the device when the critical mobility calculated in step (b) is greater than the absolute value of the electrophoretic mobility of the analyte.

2. The method of claim 1 , wherein, in step (a), the critical mobility model

is established as

μ

cr

=

μ

+

+

μ

-

I

zFQc

0

-

D

+

-

D

-

D

eff

⁢

exp

⁡

(

-

QL

D

eff

⁢

A

)

1

-

exp

⁡

(

-

QL

D

eff

⁢

A

)

 (where μ + and μ − respectively denote electrophoretic mobilities of cations and anions of an electrolyte, D + and D − respectively denote diffusion coefficients of cations and anions, D eff denotes a corrected diffusion coefficient of an electrolyte, Q denotes a flow rate of solution entering a main microchannel of the material preconcentration device, I denotes an ion current, A denotes a cross-sectional area of the main microchannel of the material preconcentration device, L denotes a length of the main microchannel, c 0 denotes a bulk concentration of the electrolyte, z denotes an ion valence of the analyte, and F denotes a Faraday constant).

3. The method of claim 2 , wherein, in step (b), the parameter value is applied by substituting an operating condition of the material preconcentration device in the critical mobility model.

4. The method of claim 3 , wherein the parameter value includes:

a flow rate Q of solution entering the main microchannel of the material preconcentration device,

an ion current I,

a cross sectional area A of the main microchannel of the material preconcentration device, and

a length L of the main microchannel.

5. The method of claim 1 , wherein an equilibrium position of preconcentration of the analyte in the material preconcentration device is determined as a sum of advection caused by a flow of the analyte and electro-migration of the analyte caused by an electrophoretic mechanism, wherein the equilibrium position of the preconcentration of the analyte propagates in an inlet/outlet direction during preconcentration.

6. The method of claim 1 , wherein the material preconcentration device comprises a main microchannel having an inlet at one end for supplying the analyte thereto, and an ion selective membrane provided on at least one surface of the main microchannel, and

wherein, when an electric field is applied to the material preconcentration device, an ion concentration polarization (ICP) phenomenon occurs in a part of the main microchannel adjacent to the ion selective membrane which causes an ion depletion layer to be generated.

7. The method of claim 6 , wherein the ion-selective membrane is made of C 7 HF 13 O 5 S.C 2 F 4 .

8. A method of determining whether an equilibrium position of preconcentration of an analyte to be preconcentrated in a material preconcentration device propagates in the device, the method comprising:

(a) establishing a critical mobility model that determines whether a mechanism for advection or electro-migration is dominant during preconcentration of the analyte based on a comparison of an absolute value of an electrophoretic mobility of the analyte with a critical mobility of the analyte;

(b) calculating a critical mobility of the analyte by applying a parameter value to the critical mobility model, wherein the parameter value comprises an operating condition of the material preconcentration device;

(c) inputting an analyte to the material preconcentration device;

(d) operating the material preconcentration device to preconcentrate the analyte; and

(e) determining that an equilibrium position of preconcentration of the preconcentrated analyte propagates in the device when the critical mobility calculated in step (b) is less than the absolute value of the electrophoretic mobility of the analyte.

9. The method of claim 8 , wherein, in step (a), the critical mobility model

is established as

μ

cr

=

μ

+

+

μ

-

I

zFQc

0

-

D

+

-

D

-

D

eff

⁢

exp

⁡

(

-

QL

D

eff

⁢

A

)

1

-

exp

⁡

(

-

QL

D

eff

⁢

A

)

 (where μ+ and μ− respectively denote electrophoretic mobilities of cations and anions of an electrolyte, D+ and D− respectively denote diffusion coefficients of cations and anions, Deff denotes a corrected diffusion coefficient of an electrolyte, Q denotes a flow rate of solution entering) a main microchannel of the material preconcentration device, I denotes an ion current, A denotes a cross-sectional area of the main microchannel of the material preconcentration device, L denotes a length of the main microchannel, c o denotes a bulk concentration of the electrolyte, z denotes an ion valence of the analyte, and F denotes a Faraday constant).

10. The method of claim 9 , wherein, in step (b), the parameter value is applied by substituting an operating condition of the material preconcentration device in the critical mobility model.

11. The method of claim 10 , wherein the parameter value includes:

a flow rate Q of solution entering the main microchannel of the material preconcentration device,

an ion current I,

a cross-sectional area A of the main microchannel of the material preconcentration device, and

a length L of the main microchannel.

12. The method of claim 8 , wherein the equilibrium position of preconcentration of the analyte in the material preconcentration device is determined as a sum of advection caused by a flow of the analyte and electro-migration of the analyte caused by an electrophoretic mechanism, wherein the equilibrium position of the preconcentration of the analyte propagates in an inlet/outlet direction during preconcentration.

13. The method of claim 8 , wherein the material preconcentration device comprises a main microchannel having an inlet at one end for supplying the analyte thereto, and an ion-selective membrane provided on at least one surface of the main microchannel, and

wherein, when an electric field is applied to the material preconcentration device, an ion concentration polarization (ICP) phenomenon occurs in a part of the main microchannel adjacent to the ion-selective membrane which causes an ion depletion layer to be generated.

14. The method of claim 13 , wherein the ion-selective membrane is made of C 7 HF 13 O 5 S.C 2 F 4 .