A radiofrequency plasma in a polydimethylsiloxane (PDMS) microchip

Lim, Heung Bin; Kim, Dong-Hoon; Jung, T.R.; Houk, R. S.; Kim, Yangsun

doi:10.1016/j.aca.2005.04.067

Cited by 10 publications

(5 citation statements)

References 12 publications

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“…Rotational temperature of plasmas was estimated using Boltzmann plots and the Q1 branch from Q 1 (2) to Q 1 (14) in the 3075-3115 Å region of the OH radical. Figure 2 shows OH spectrum generated by the He-plasma.…”

Section: Resultsmentioning

confidence: 99%

“…Various types of micro plasmas have been recently described, such as, CCP, 7-9 MIP, 4,10,11 ICP, 12,13 and others, which can detect halogens. However, argon plasmas have insufficient energy to excite halogens, 14 and thus, helium has been used instead due to the higher excitation and ionization energy. The thermal properties of plasmas can be estimated using several techniques, such as, mass spectrometry, Langmuir probe, and optical techniques.…”

Section: Introductionmentioning

confidence: 99%

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He-Polymer Microchip Plasma (PMP) System Incorporating a Gas Liquid Separator for the Determination of Chlorine Levels in a Sanitizer Liquid

2009

Bulletin of the Korean Chemical Society

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The authors describe an analytical method to determine total chlorine in a sanitizer liquid, incorporating a lab-made He-rf-plasma within a PDMS polymer microchip. Helium was used instead of Ar to produce a plasma to achieve efficient Cl excitation. A quartz tube 1 mm i.d. was embedded in the central channel of the polymer microchip to protect it from damage. Rotational temperature of the He-microchip plasma was in the range 1350-3600 K, as estimated from the spectrum of the OH radical. Chlorine was generated in a volatilization reaction vessel containing potassium permanganate in combination of sulfuric acid and then introduced into the polymer microchip plasma (PMP). Atomic emission lines of Cl at 438.2 nm and 837.7 nm were used for analysis; no emission was observed for Ar plasma. The achieved limit of detection was 0.81 µg mL -1 (rf powers of 30-70 W), which was sensitive enough to analyze sanitizers that typically contained 100-200 µg mL -1 of free chlorine in chlorinated water. This study demonstrates the usefulness of the devised PMP system in the food sciences and related industries.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

He-Polymer Microchip Plasma (PMP) System Incorporating a Gas Liquid Separator for the Determination of Chlorine Levels in a Sanitizer Liquid

2009

Bulletin of the Korean Chemical Society

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“…Then, the microarray chips were treated with oxygen plasma for 30 s to render the exposed PDMS pillars hydrophilic. 24,25 3-Glycidoxypropyl-trimethoxysilane (GPTMS, 98%, Sigma-Aldrich) was inserted as a linker on the pillars to improve the reactivity and immobilization efficiency of IgG. For this, 500 mL of GPTMS was deposited on each chip by chemical vapor deposition in a vacuum of 70 Torr at 100 C for 2 h. Then, each chip was washed with ethyl alcohol (99.9%, Duksan, Korea) and dried with flowing He gas.…”

Section: Experimental Immobilization Of Immunoglobulin G (Igg) On Mic...mentioning

confidence: 99%

LA-ICP-MS with microarray chip sampling to determine holoceruloplasmin in serum

Joo

Lim

2012

J. Anal. At. Spectrom.

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An analytical method was developed to determine holoceruloplasmin (holo-CP) concentration in serum using laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS). Since each holo-CP in serum contains six Cu ions, the concentration was estimated quantitatively by determining the Cu concentration. For small sample consumption, polydimethylsiloxane (PDMS) microarray chips with 150 mm diameter pillars were manufactured. The surface of each pillar was immobilized by a ceruloplasmin (CP) antibody (IgG) for an antigen-antibody reaction to afford high selectivity for the sampling of total CP in the serum matrix. A calibration curve with a linear regression coefficient of 0.992 was obtained by standard addition methods. For demonstration, 126 pL of human serum was loaded on each pillar of the microarray chips and analyzed by LA-ICP-MS in single-shot mode. The determined concentration of holo-CP was compared with that of the total CP estimated by competitive enzyme linked immunosorbent assay (ELISA), from which the concentration of apoceruloplasmin (apo-CP) was deduced. In conclusion, this analytical method for determining holo-CP concentration with high selectivity and small sample volume can be used in the confirmative diagnosis of diseases related to copper deficiency in clinical samples.

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“…RF power of 500 W and 50 kHz (Corona Treatment Generator HK-2000, Hankook High Frequency, Goyang-si, Korea) was used for 30 s at atmospheric pressure for the plasma treatment, optimized in the lab. 23,24 Finally, the PDMS plate with 5 Â 5 and 6 Â 7 arrays of islands, $150 mm in diameter and 100 mm in height, was cut into $4 Â 4 mm chips. Since the hydrophilic surface is unstable due to the diffusion of low molecular weight chains, 25,26 the chip with mask film was re-treated if not used within 30 min.…”

Section: Experimental Manufacturing Microchipmentioning

confidence: 99%