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Functionalized Graphene-Coated Cobalt Nanoparticles for Highly Efficient Surface- Assisted Laser Desorption/Ionization Mass Spectrometry Analysis Hideya.

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Presentation on theme: "Functionalized Graphene-Coated Cobalt Nanoparticles for Highly Efficient Surface- Assisted Laser Desorption/Ionization Mass Spectrometry Analysis Hideya."— Presentation transcript:

1 Functionalized Graphene-Coated Cobalt Nanoparticles for Highly Efficient Surface- Assisted Laser Desorption/Ionization Mass Spectrometry Analysis Hideya Kawasaki, Keisuke Nakai, Ryuichi Arakawa, Evagelos K. Athanassiou, Robert N. Grass and Wendelin J. Stark Anal. Chem. 2012, 84, 報告者 : 王碩鋒 2013/04/18 地點 :R108

2 Outline Introduction Mass MALDI & SALDI Analyte Experiment Results and Discussion Conclusion 2

3 Introduction 離子源 離子偵測器 ESI LDI EI CI quadrupole time-of-flight ion trap 將自質量分析器飛出 之離子,激發電子產 生並放大訊號 Mass Spectrometry Introduction 3 MALDI 質量分析器

4 CHEMISTRY ( THE CHINESE CHEM. SOC., TAIPEI ) September Vol. 64,No.4, pp.459~468 Introduction Laser Desorption Ionization (雷射脫附法) 1. 約在 1960 年代發展。 2. 主要偵測小分子的無機有機物。 3. 直接以高能雷射轟擊分析物產生脫附游離。 4. 缺點: 使分析物易碎裂成碎片 Introduction 4

5 Matrix Assisted Laser Desorption Ionization (1)Sweet spot (2)Shot to shot Reproducibility (3)Protein complexes are unstable under strongly acidic conditions (a)2,5-dihydroxybenzic acid(DHB) (b)Sinapinic acid(SA) (c)CHCA dry Introduction 5

6 Surface Assisted Laser Desorption Ionization(SALDI) 優點 : (1) 無機基質上可吸附較多分析物 SALDI: analyte molecules MALDI: analyte molecules (2) 具有較高的再現性 (3) 基質具有對特定分子的專一性 缺點 : 分析分子量較低 ( 一般低於 30000) 種類 : (a)Au,Ag,SiO 2 (b)Co 6

7 Introduction Magnetic nanoparticles (1) high surface area (2) affinity for the specific analytes (3) efficient extraction of analytes (4) easily oxidized in air

8 Introduction CoC−NH2 nanomagnets (1)Graphene has outstanding physical,Graphene and chemical properties (2) increase ion yields (3) affinity for the specific analytes

9 Introduction Graphene (1)maximum UV absorption at 270 nm (2)high surface area (3) good energy transfer ability (4) less interference of matrix-related ions

10 Introduction polyfluorinated compounds (PFCs)PFCs Compounds in this class were firstproduced in the 1940s and1950s. By the early 2000s, when it became apparent that PFCs were broadly distributed in the environment. Perfluorooctanesulfonic acid (PFOS)PFOS

11 PFCs

12 PFOS An increase in hepatocellular adenomas and thyroid follicular cell adenomas was observed in rats exposed to high levels of PFOS in their food the half-life of PFOS in humans is approximately 5.4 years

13 EXPERIMENTAL SECTION Method 1 two-layer sample preparation method CoC−NH2 Nanomagnetssample

14 EXPERIMENTAL SECTION Method 2

15 RESULTS AND DISCUSSION

16 Characterization of Modified and Unmodified CoC Nanomagnets. Unmodified CoC Nanomagnets.

17 Characterization of Modified and Unmodified CoC Nanomagnets. Functionalization of carbon-coated magnetic nanobeads with chlorobenzene and nitrobenzene and reduction of the nitro groups to amino groups with elemental sulfur. SDS=sodium dodecylsulfate

18 Characterization of Modified and Unmodified CoC Nanomagnets.

19 Affinity SALDI-MS Using Modified and Unmodified CoC−NH 2 Nanomagnets. angiotensin II m/z: 1047

20 Affinity SALDI-MS Using Modified and Unmodified CoC−NH 2 Nanomagnets. Graphene oxide (SY = 0.38) a hybrid film of poly(allylamine hydrochloride)- functionalized graphene oxide and gold nanoparticles (SY = 0.78)

21 Affinity SALDI-MS Using Modified and Unmodified CoC−NH 2 Nanomagnets.

22 Extraction of PFOS from Water Using CoC−NH 2 Nanomagnets and SALDI-MS Detection.

23 PFOS pKa:−3.27 pH < 7pH 11

24 Extraction of PFOS from Water Using CoC−NH 2 Nanomagnets and SALDI-MS Detection.

25 LOD The recovery ratio of PFOS from 1 L of 10 ppt PFOS aqueous solution using CoC−NH2 nanomagnets was more than 99%.

26 Extraction of PFOS from Water Using CoC−NH 2 Nanomagnets and SALDI-MS Detection. Tap water sample

27 Extraction of PFCs with Different Chain Lengths from Water Using CoC−NH 2 Nanomagnets, Followed by SALDI-MS Detection.

28

29 CONCLUSIONS 1.We have demonstrated that CoC−NH2 nanomagnets work well in tandem with SALDI-MS as a LDI-assisting material and for the extraction/enrichment of analytes from dilute solution. 2.The benzylamine surface modification of the CoC nanomagnets was shown to increase the ion yield of angiotensin II and decrease ion fragmentation of benzylpyridinium ions. 3.SALDI-MS using CoC−NH2 nanomagnets enabled the detection of various small molecule drugs,but the detection of the small acidic drug molecules acetylsalicylic acid and ibuprofen were not achieved with this approach. 4.The detection sensitivities of PFCs were 0.1 ppt for PFOS (C8), 10 ppt for PFHxS (C6), and 10 ppt for PFBS (C4). 5.In future work, it may be interesting to detect aromatic compounds as aqueous environmental samples using affinity SALDI-MS with CoC−NH2 nanomagnets.

30 CONCLUSIONS In fact, preliminary experiment indicated that the detection of pentachlorophenol (20 ppb) in water, was accomplished by the use of affinity SALDIMS with CoC−NH2 nanomagnets.

31 Thanks for your attention!!


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