Apparatus for solution component analysis and fabricating method thereof

The present invention provides an apparatus for solution component analysis and fabricating method thereof, by which a mixing channel, reaction channel, and measurement channel are formed as continuous micro-grooves on one substrate to implement the miniature apparatus for analyzing solution components, by which the apparatus is provided with portability facilitating access to a spot outside a laboratory to perform an instant sample analysis, and by which an optical system configuration for sample analysis can be simplified in a manner of facilitating an optical transfer by forming a transparent silicon oxide (SiO2) layer between a micro channel of the apparatus and an optical fiber to insert the optical fiber therein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for analyzing solution components and fabricating method thereof, and more particularly, to an apparatus for solution component analysis and fabricating method thereof, by which a mixing channel, reaction channel, and measurement channel are formed as continuous micro-grooves on one substrate to implement the miniature apparatus for analyzing solution components and by which the apparatus is provided with portability for instant sample analysis.

The solution component analyzing apparatus according to the present invention is to decide the sort of an unknown solution component using the Beer-Lambert Principle and to measure a concentration of the solution component.

2. Discussion of the Related Art

FIG. 1is a schematic diagram of a solution component analyzing apparatus according to prior art.

Referring toFIG. 1, a solution component analyzing apparatus according to prior art comprises a light source10, a monochromator20separating a light of the light source10into multi-wavelength lights, a transparent sample vessel30transmitting the multi-wavelength lights separated by the monochromator20and holding a sample solution therein, and a light-receiving unit50receiving the multi-wavelength lights transmitted through the transparent sample vessel30via an optical system40to measure a light intensity.

The light source10employs such a light source as a xenon lamp, tungsten-halogen lamp, and the like, which emit a continuous light. The light emitted from the light source10is separated into the multi-wavelength lights using the monochromator having a diffraction grid or an optical filter.

The separated multi-wavelength lights pass through the transparent sample vessel30filled up with a measurement sample solution.

In doing so, some of the multi-wavelength lights passing through the transparent sample vessel30are absorbed in a measurement sample solution component, whereas the others of the multi-wavelength lights pass through the transparent sample vessel30. And, a light-receiving sensor of the light-receiving unit50measures the variation of the light intensity for each wavelength band on the multi-wavelength lights having passed through the transparent sample vessel30.

FIG. 2is an exemplary graph of measurement by a solution component analyzer according to prior art.

Referring toFIG. 2, a light having a specific wavelength band is absorbed in a sample solution so that the light-receiving unit50measures a variation that a light intensity decreases like ‘a’. A pattern of a photo-absorption spectrum can be more complicated according to the sample solution. And, a component and concentration within the sample solution can be determined using the pattern of the photo-absorption spectrum and the light intensity variation of the pattern.

However, the prior art solution component analyzer comprising the light source, monochromator, sample vessel, light-receiving sensor, and the like, increases in its volume and weight, thereby failing to facilitate its portability.

And, in order to prepare the sample solution for measuring the component within the solution and the concentration of the component, the related art solution component analyzer additionally needs a mixer or reactor for mixing additives to meet acidity (pH) of the sample solution or catalyst additives for accelerating reaction. Moreover, the prior art solution component analyzer occasionally needs such an equipment as a separator for separating only the measurement sample solution. For such reasons, it is difficult to instantly analyze the components of a solution collected on the spot outside a laboratory equipped with the prior art solution component analyzer. And, it takes a considerably long period of time to analyze the components.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to an apparatus for solution component analysis and fabricating method thereof that substantially obviate one or more problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide an apparatus for solution component analysis and fabricating method thereof, by which a mixing channel, reaction channel, and measurement channel are formed as continuous micro-grooves on one substrate to implement the miniature apparatus for analyzing solution components and by which the apparatus is provided with portability facilitating access to a spot outside a laboratory to perform an instant sample analysis.

Another object of the present invention is to provide an apparatus for solution component analysis and fabricating method thereof, by which an optical system configuration for sample analysis can be simplified in a manner of facilitating an optical transfer by forming a transparent silicon oxide (SiO2) layer between a micro channel of the apparatus and an optical fiber to insert the optical fiber therein.

To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, an apparatus for solution component analysis according to the present invention comprises a plurality of grooves, which is formed on a substrate, comprising a plurality of sample inlets; a plurality of microchannels connected to a plurality of the sample inlets to enable a plurality of samples to flow therein, respectively; a mixing channel communicating with a plurality of the microchannels to mix a plurality of the samples within a plurality of the microchannels; a reaction channel enabling the samples mixed in the mixing channel to react; a measurement channel measuring the samples having reacted in the reaction channel; and an outlet discharging the samples having completed a measurement in the measurement channel, wherein the measurement channel comprises an input microchannel connected to the reaction channel to receive the reaction-completed samples from the reaction channel, a straight microchannel enabling the reaction-completed samples via the input microchannel to flow straight and to transmit a light in a direction that the reaction-completed samples flow, and an output microchannel outputting the samples having passed through the straight microchannel to the outlet; optical fiber insertion grooves provided on the substrate to communicate with both ends of the straight microchannel, respectively; first and second optical fibers inserted to be fixed in the optical fiber insertion grooves so that the light can be inputted and outputted via the first and second optical fibers, respectively; and a transparent layer between the measurement channel and each of the optical fiber insertion grooves.

In another aspect of the present invention, a method of fabricating an apparatus for solution component analysis comprises a first step of forming a plurality of grooves and optical fiber insertion grooves to insert a plurality of optical fibers therein, respectively, on a first substrate, wherein a plurality of the grooves comprise a plurality of sample inlets, a plurality of microchannels connected to a plurality of the sample inlets, respectively, a mixing channel communicating with a plurality of the microchannels, a reaction channel communicating with the mixing channel, a measurement channel communicating with the reaction channel, and an outlet communicating with the measurement channel; a second step of bonding a second substrate having perforated holes for solution injection and discharge onto the first substrate, wherein the perforated holes correspond to the sample injection inlet and the outlet, respectively; and a third step of inserting first and second optical fibers in the optical fiber insertion grooves, respectively.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 3is a layout of an apparatus for solution component analysis according to the present invention.

Referring toFIG. 3, an apparatus for solution component analysis according to the present invention comprises a plurality of grooves formed on a substrate. A plurality of the grooves comprise a plurality of sample inlets110, a plurality of microchannels115connected to a plurality of the sample inlets110to enable a plurality of samples to flow therein, respectively, a mixing channel120connected to a plurality of the microchannels115to mix a plurality of the samples, a reaction channel130enabling the samples mixed in the mixing channel120to react, a measurement channel140measuring the samples having reacted in the reaction channel130, and an outlet150discharging the samples having completed a measurement in the measurement channel. The measurement channel140comprises an input microchannel141connected to the reaction channel130to receive the reaction-completed samples from the reaction channel130, at least one straight microchannel140enabling the reaction-completed samples via the input microchannel141to flow straight and to transmit a light in a direction that the reaction-completed samples flow, and an output microchannel142outputting the samples having passed through the straight microchannel140to the outlet150. Optical fiber insertion grooves161and162are provided on the substrate to be connected to both ends of each of the at least one or more straight microchannels140, respectively. And, first and second optical fibers are inserted to be fixed in the optical fiber insertion grooves161and162so that the light can be inputted and outputted via the first and second optical fibers, respectively. Moreover, the at least one or more straight microchannels140differ from each other in length so that a plurality of the straight microchannels can communicate with each other.

Thus, if photo-absorption of the measurement sample is high and if a length of the measurement channel is long, the light incident on the measurement sample solution is entirely absorbed in the sample solution, whereby the variation of the light intensity cannot be measured in the light-receiving unit.

In this case, the straight microchannel140having a shorter length is selected to lower the photo-absorption, whereby the variation of the light intensity according to the photo-absorption can be measured.

And, if photo-absorption of the measurement sample is low and if the length of the measurement channel is short, the light incident on the measurement sample solution is barely absorbed in the sample solution, whereby the variation of the light intensity cannot be measured in the light-receiving unit.

In this case, the straight microchannel140having a longer length is selected to raise the photo-absorption, whereby the variation of the light intensity according to the photo-absorption can be measured.

FIG. 4is a diagram for explaining a method of measuring a component and concentration of a sample solution using a measurement channel and optical fibers of an apparatus for solution component analysis according to the present invention. Referring toFIG. 4, the input microchannel141receives the reacted sample from the reaction channel. When the reacted sample having passed through the input microchannel141straightly flows through the straight microchannel140, the light irradiated from the light source181is passed through a first optical fiber171to pass through the sample which is flowing in the straight microchannel140.

In doing so, the sample solution contains a substance of a specific component so that a pattern variation of a photo-absorption spectrum occurs in a specific wavelength band of the light that is passing through the sample solution.

Subsequently, a second optical fiber172receives the light having passed through the sample to transfer to the light-receiving unit182. In doing so, the light-receiving unit182comprising a light-receiving sensor or spectrometer measures the variation of the light intensity according to the wavelength of the light having passed through the sample.

Thereafter, the sample having completed its measurement in the straight microchannel140is discharged from the outlet via the output microchannel142.

FIGS. 5A to 5Dare cross-sectional diagrams of a method of fabricating an apparatus for solution component analysis according to the present invention.

Referring toFIG. 5B, a plurality of ‘␣’ type microchannel grooves201including sample injection inlets, microchannels connected to the sample injection inlets, respectively, a mixing channel communicating with the microchannels, a reaction channel communicating with the mixing channel, a measurement channel communicating with the reaction channel, and an outlet connected to the measurement channel and ‘␣’ type optical fiber insertion grooves202aand202bto insert and fix optical fibers thereto, respectively, are simultaneously formed on the first substrate200.

In this case, the first substrate200is a silicon substrate and the microchannel grooves201and the optical fiber insertion grooves202aand202bare formed by etching the silicon substrate vertically using silicon deep etching.

Referring toFIG. 5C, a second substrate210having perforated holes211and212for solution injection and discharge is attached on the first substrate200on which the process inFIG. 5Bhas been performed so that the perforated holes211and212can correspond to the microchannel grooves of the sample inlet and outlet on the first substrate200.

In doing so, the second substrate210can be formed of glass or PDMS (polydimethylsiloxane). In case that the second substrate210is a glass substrate, the second substrate210is assembled to the first substrate200by anodic bonding so that the sample can flow inside the microchannel grooves201.

Referring toFIG. 5D, first and second optical fibers301and302are inserted in the optical fiber insertion grooves202aand202b, respectively.

FIG. 6AandFIG. 6Bare magnified layouts for explaining a process of forming a transparent silicon oxide (SiO2) layer between a measurement channel and an optical fiber insertion groove.

In case that the substrate100of the apparatus for solution component analysis according to the present invention is a silicon substrate,FIG. 6Ashows that the measurement channel140, input microchannel141, and optical insertion groove161are formed by etching the silicon substrate vertically using deep etching.

In this case, a silicon layer145having a thickness ‘d’ of several micrometers is formed between the measurement channel140and the optical fiber insertion groove161.

Since the silicon layer145has a very small light transmittance in a visible ray band, the optical transmission loss increases in the process of transferring the light coming out of the optical fiber to the measurement channel140.

In order to solve the problem, the silicon substrate is oxidized to form a transparent layer as the silicon layer145to provide a high light transmittance in the visible ray band.

Referring toFIG. 6B, by the oxidation of the silicon substrate, a silicon oxide layer146is formed at an interface between the measurement channel140and the optical fiber insertion groove161the moment the silicon layer145is turned into the silicon oxide (SiO2) layer146.

Therefore, the transparent layer having a high light transmittance in the visible ray band can be provided between the measurement channel140and the optical fiber insertion groove161.

And, the transparent silicon oxide layer146prevents the sample solution from leaking toward the optical fiber from the measurement channel140and is operative in transferring the light coming out of the optical fiber to the measurement channel140smoothly.

FIG. 7is a magnified layout of an optical fiber inserted in an optical fiber insertion groove according to the present invention. Referring toFIG. 7, since the transparent silicon oxide layer146has the length of several micrometers, distortion of the layer146may be caused by the layer stress on forming the silicon oxide layer.

In order to minimize the distortion, an opening area of the transparent silicon oxide layer146formed in a direction of the optical fiber is formed as small as possible within a range failing to affect the light transfer of the optical fiber.

After the optical fiber171has been inserted in the optical fiber insertion groove161, in order to prevent the transparent silicon oxide layer146from being broken by the pressure of the sample solution flowing in the measurement channel140and to minimize Fresnel Reflection between the silicon oxide layer146and the optical fiber171, a space between the transparent silicon oxide layer146and the optical fiber171is filled up with UV-hardening type transparent epoxy191.

FIG. 8is a cross-sectional diagram of a micro heater and temperature sensor provided beneath a substrate corresponding to an area where a reaction channel of an apparatus for solution component analysis according to the present invention exists.

Referring toFIG. 8, in order to enable chemical reaction to occur more favorably by maintaining a uniform temperature of the sample solution within the reaction channel130, a micro heater500and a temperature sensor501are further provided beneath the substrate100corresponding to the area where the reaction channel130exists.

Since the reaction channel is constructed with a microchannel, the mixed sample solution may proceed to the measurement channel from the reaction channel to be measured before reacting sufficiently. Hence, in order to enable the sample solution passing through the reaction channel to react chemically and sufficiently in a short time, the micro heater500is provided to the bottom of the substrate100and the temperature sensor501is provided to control the temperature of the micro heater500as well.

As mentioned in the foregoing description of the apparatus for solution component analysis according to the present invention, the mixing, reaction, and measurement channels are continuously connected in turn, whereby it is possible to considerably reduce the size of the microanalysis apparatus.

And, the transparent silicon oxide layer is formed between the measurement channel and the optical fiber to facilitate the light transfer via the inserted optical fibers, thereby enabling to simplify the configuration of the optical system for sample analysis.

Accordingly, in the present invention, the mixing channel, reaction channel, and measurement channel are formed as a continuous micro-groove on one substrate to implement the miniature apparatus for analyzing solution components and the apparatus is provided with portability facilitating access to a spot outside a laboratory to perform an instant sample analysis. Moreover, in the present invention, an optical system configuration for sample analysis can be simplified in a manner of facilitating an optical transfer by forming a transparent silicon oxide layer between a micro channel of the apparatus and an optical fiber to insert the optical fiber therein.