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

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, 9268-9275報告者 : 王碩鋒2013/04/18地點 :R108

2

Outline

IntroductionMass

MALDI＆ SALDI

Analyte

Experiment

Results and Discussion

Conclusion

Introduction

離子源離子源離子偵測器

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

CHEMISTRY（ THE CHINESE CHEM. SOC., TAIPEI） September. 2006 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

IntroductionMatrix 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

IntroductionSurface Assisted Laser Desorption Ionization(SALDI)

優點 :(1) 無機基質上可吸附較多分析物 SALDI: 107-109 analyte molecules MALDI:103-105analyte 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,SiO2

(b)Co

6

IntroductionMagnetic nanoparticles

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

IntroductionCoC−NH2 nanomagnets

(1) Graphene has outstanding physical, and chemical properties(2) increase ion yields(3) affinity for the specific analytes

Introductionpolyfluorinated compounds (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

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

EXPERIMENTAL SECTION

Method 1two-layer sample preparation method

CoC−NH2 Nanomagnets sample

EXPERIMENTAL SECTION

Method 2

RESULTS AND DISCUSSION

Characterization of Modified and Unmodified CoC Nanomagnets.

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=sodiumdodecylsulfate


Affinity SALDI-MS Using Modified and Unmodified CoC−NH2 Nanomagnets.

angiotensin IIm/z: 1047


Graphene oxide (SY = 0.38)

a hybrid film of poly(allylaminehydrochloride)-functionalized graphene oxide and gold nanoparticles(SY = 0.78)


Extraction of PFOS from Water Using CoC−NH2 Nanomagnets and SALDI-MS Detection.


PFOS pKa:−3.27

pH < 7pH 11



LOD

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


Tap water sample

Extraction of PFCs with Different Chain Lengths from Water Using CoC−NH2 Nanomagnets, Followed by SALDI-MS Detection.

Extraction of PFCs with Different Chain Lengths from Water Using CoC−NH2 Nanomagnets, Followed by SALDI-MS Detection.

CONCLUSIONS1.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.

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.

Thanks for your attention!!

Documents

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