Caution! Several chemicals (e.g., acrylamide, 1,1'-dichloroethene) used in these procedures are acutely toxic and carcinogenic. Consult all relevant material safety data sheets (MSDS) prior to use. Follow appropriate safety practices when performing the experiments.
Note: Unless otherwise stated, carry out all procedures at ambient temperature in a class 100 laminar flow hood.
1. Fabrication of the Dipole-assisted SPE Microchip
2. Surface Verification of PMMA Modification
3. Characterization of the Dipole-assisted SPE Reaction
Figure 2 depicts the reaction that occurs during the channel modification procedures of the PMMA microchip. Contact angle analysis was used to monitor the surface changes during the proposed procedures. An LA-ICP-MS system and a dispersive Raman spectrometer were employed to verify the successful modification of the C-Cl moieties formation on the PMMA substrate (Figure 3(a),(b)). The proposed dipole-assisted SPE reaction was characterized by the XANES analysis (Figure 4).
Figure 1. The PMMA microchip. (a) The snapshot of the pattern file for the fabricated microchip. (b) Layout of the fabricated microchip: S, E, and B represent the introduction ports for the sample, eluent, and buffer solutions, respectively; O represents the outlet. The black circle represents the drilled access hole for each. The channels used for the introduction of sample and buffer solutions both formed an angle of 30° with the extraction channel. The length of the effective extraction channel, which was defined as the distance from the convergence point of the flows of the sample and buffer solutions to the confluent outlet, was 94 mm. (c) The photograph of the cross-section of the machined plate. Reproduced from Ref. 16 by permission of The Royal Society of Chemistry. Please click here to view a larger version of this figure.
Figure 2. Scheme of the channel modification for the PMMA microchip. The inset photographs show the contact angle corresponding to the resulting product in sequence. The contact angle was determined by using an image of a water drop. The average of three repeated measurements was used for determining the reported contact angles in each case. Reproduced from Ref. 16 by permission of The Royal Society of Chemistry. Please click here to view a larger version of this figure.
Figure 3. Surface verification of PMMA modification. (a) Signal for Cl obtained by ablating both the PMMA and PMMA modified with the C-Cl moieties. The inset shows the ablation positions corresponding to each obtaining signal. (b) Raman spectra of native and modified PMMA. Reproduced from Ref. 16 by permission of The Royal Society of Chemistry. Please click here to view a larger version of this figure.
Figure 4. Mn K-edge XANES spectra of modified PMMA and modified PMMA treated with Mn2+ ions. The spectra of modified PMMA was presented as red line. The interactions between the highly electronegative C-Cl moieties of modified PMMA and the Mn2+ ions shown the absorption spectra was presented as blue line. Reproduced from Ref. 16 by permission of The Royal Society of Chemistry. Please click here to view a larger version of this figure.
AutoCAD | Autodesk | N/A | http://www.autodesk.com/education/free-software/autocad |
Poly(methyl methacrylate) (PMMA) sheet | Kun Quan Engineering Plastics | N/A | 350 mm (L) x 20 mm (W) x 2 mm (H). The glass transition temperature (Tg) of PMMA sheets is ranged from 102–110 °C. The UV transmittance of the PMMA at 365 nm is 91.2%. |
Micromachining system | Laser Life | LES-10 | Maximum laser power: 10 W. Maximium engraving speed: 762 mm s−1. |
High-resolution optical microscope | Ching Hsing Computer-Tech | FS-230 | |
Power Image Analysis system (PIA) | Ching Hsing Computer-Tech | PIA V16.1 | |
Multi drilling machines | N/A | LT-848 | |
Deionized water (D. I. H2O) | Millipore | Milli-Q Integral 5 System | |
Sodium dodecyl sulfate (SDS) | J. T. Baker | 4095-04 | |
Ultrasound oscillator | Elma | Transsonic Digital | |
Glass board | N/A | N/A | 160 mm (L) x 35 mm (W) x 2 mm (H); fragile |
Binder clip | SDI | 0234T-1 | http://stationery.sdi.com.tw/product_detail.php?Key=322&cID=55&uID=6 |
Precision oven | Yeong Shin | DK-45 | |
Poly(etheretherketone) (PEEK) tube | VICI | JR-T-6002 (0.5 mm i.d.); JR-T-6001 (0.25 mm i.d.) | |
Polymer tubing cutter | Upchurch Scientific | A-327 | |
Two-component epoxy-based adhesive | Richwang | N/A | Skin irritative. The major components are an epoxy resin and a hardener. |
Peristaltic pump | Gilson | Minipuls 3 | |
Peristaltic tube | Gilson | F117934 | |
Sodium hydroxide (NaOH) | Sigma–Aldrich | 30620 | |
Nitric acid (HNO3) | J. T. Baker | 959834 | |
Acrylamide (prop-2-enamide, C3H5NO) | Sigma–Aldrich | A8887 | Acutely toxic and carcinogenic |
In-house-built photomask | N/A | N/A | The in-house-built photomask was made of a black paper (114 mm (L) × 22 mm (W)) that contained an open window (94 mm (L) × 2 mm (W)) allowing the desired region |
1,1-Dichloroethylene | Sigma–Aldrich | 163032 | Acutely toxic and carcinogenic |
Cartridge | Dikma | ProElut AL-B | |
2,2-Azobisisobutyronitrile (AIBN, C8H12N4) | Showa Chemical | 0159-2130 | |
Ethanol | Sigma–Aldrich | 32221 | |
Hexanes (C6H14) | Millinckrodt Chemical | 5189-08 | |
In-house-built irradiation system | Great Lighting (UV-A lamp) | N/A | An opaque box with an UV-A lamp (40 W, maximum emission at 365 nm) |
Glass vial | Yeong Shin | 132300019 | Fragile |
Aluminum foil | Diamond | N/A | |
Conical tubes with screw caps | labcon | 3181-345-008 (50 mL); 3131-345-008 (15 mL) | |
Rocking shaker | TKS | RS-01 | |
Contact angle meter | First Ten Angstroms | FTA 125 | |
PMMA bead | Scientific Polymer Products | 037A | |
Mortar and pestle, agate | Yeong Shin | 139000004 | Fragile |
Tissue culture plate | AdvanGene Life Science Plasticware | AGC-CP-24S-50EA | 24-Well, non-treated, sterilized |
Hydraulic press | Panchum | Press-200 | |
Laser ablation | New Wave Research | NWR193 | |
Inductively coupled plasma-mass spectrometer | Agilent Technologies | Agilent 7500a | |
Glass bottle | DURAN | 21801245 (100 mL); 21801365 (250 mL) | |
Dispersive Raman spectrometer | Thermo Fisher Scientific | Nicolet Almega XR | |
Manganese nitrate tetrahydrate (Mn(NO3)2×4H2O) | Sigma–Aldrich | 63547 | |
Maleic acid disodium salt hydrate (C4H4Na2O5) | Sigma–Aldrich | M9009 | |
X-ray absorption near edge structure (XANES) | N/A | N/A | The Mn K-edge XANES analyses were conducted at 07A and 17C1 beamlines of the National Synchrotron Radiation Research Center (NSRRC) in Taiwan. |
This paper describes a fabrication protocol for a dipole-assisted solid phase extraction (SPE) microchip available for trace metal analysis in water samples. A brief overview of the evolution of chip-based SPE techniques is provided. This is followed by an introduction to specific polymeric materials and their role in SPE. To develop an innovative dipole-assisted SPE technique, a chlorine (Cl)-containing SPE functionality was implanted into a poly(methyl methacrylate) (PMMA) microchip. Herein, diverse analytical techniques including contact angle analysis, Raman spectroscopic analysis, and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis were employed to validate the utility of the implantation protocol of the C-Cl moieties on the PMMA. The analytical results of the X-ray absorption near-edge structure (XANES) analysis also demonstrated the feasibility of the Cl-containing PMMA used as an extraction medium by virtue of the dipole-ion interactions between the highly electronegative C-Cl moieties and the positively charged metal ions.
This paper describes a fabrication protocol for a dipole-assisted solid phase extraction (SPE) microchip available for trace metal analysis in water samples. A brief overview of the evolution of chip-based SPE techniques is provided. This is followed by an introduction to specific polymeric materials and their role in SPE. To develop an innovative dipole-assisted SPE technique, a chlorine (Cl)-containing SPE functionality was implanted into a poly(methyl methacrylate) (PMMA) microchip. Herein, diverse analytical techniques including contact angle analysis, Raman spectroscopic analysis, and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis were employed to validate the utility of the implantation protocol of the C-Cl moieties on the PMMA. The analytical results of the X-ray absorption near-edge structure (XANES) analysis also demonstrated the feasibility of the Cl-containing PMMA used as an extraction medium by virtue of the dipole-ion interactions between the highly electronegative C-Cl moieties and the positively charged metal ions.
This paper describes a fabrication protocol for a dipole-assisted solid phase extraction (SPE) microchip available for trace metal analysis in water samples. A brief overview of the evolution of chip-based SPE techniques is provided. This is followed by an introduction to specific polymeric materials and their role in SPE. To develop an innovative dipole-assisted SPE technique, a chlorine (Cl)-containing SPE functionality was implanted into a poly(methyl methacrylate) (PMMA) microchip. Herein, diverse analytical techniques including contact angle analysis, Raman spectroscopic analysis, and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis were employed to validate the utility of the implantation protocol of the C-Cl moieties on the PMMA. The analytical results of the X-ray absorption near-edge structure (XANES) analysis also demonstrated the feasibility of the Cl-containing PMMA used as an extraction medium by virtue of the dipole-ion interactions between the highly electronegative C-Cl moieties and the positively charged metal ions.