title: Gold nanoparticles as assisted matrices for the detection of biomolecules in a high-salt solution through laser desorption/ionization mass spectrometry.
abstract: Citrate-capped gold nanoparticles (AuNPs) serve as matrices for the determination of biomolecules in a high-salt solution through matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). In the case of using 2,5-dihydroxybenzoic acid (2,5-DHB) as a matrix, the signal intensities of neutral steroids were severely suppressed in a high-salt solution. A high concentration of NaCl caused the formation of the sodium adduct ions during the desorption/ionization process, resulting in a decrease of the signal intensities of the protonated ions. In comparison, by applying AuNP-assisted LDI-TOF-MS, the signal intensities of neutral steroids remained almost constant when the concentration of NaCl was increased to 500 mM. Because the use of citrate-capped AuNPs as matrices primarily offers alkali metal ion adducts, AuNP matrices have a higher tolerance to high NaCl concentrations relative to that of 2,5-DHB matrices. The relevant phenomena are also discovered in the case of analysis of neutral carbohydrate, monosialoganglioside, indolamine, and angiotensin I. The quantification of small molecules in a high-salt solution has been accomplished by AuNP-assisted LDI-TOF-MS coupled to a unique sample preparation, in which samples are deposited onto the sample plate before AuNPs. The present method has been further applied to the determination of urea, creatinine, uric acid, and glucose in a urine sample.
authors.affiliation: Department of Chemistry, National Sun Yat-sen University, Taiwan.
authors.forename: Hsin-Pin
authors.initials: HP
authors.lastname: Wu
authors.forename: Cheng-Ju
authors.initials: CJ
authors.lastname: Yu
authors.forename: Chin-Yu
authors.initials: CY
authors.lastname: Lin
authors.forename: Yen-Hsiu
authors.initials: YH
authors.lastname: Lin
authors.forename: Wei-Lung
authors.initials: WL
authors.lastname: Tseng
mesh_terms: D000803:Angiotensin I / Q000032:analysis; D002241:Carbohydrates / Q000032:analysis; D019343:Citric Acid / Q000737:chemistry; D003404:Creatinine / Q000652:urine; D005260:Female; D005677:G(M1) Ganglioside / Q000032:analysis; D005732:Gangliosides / Q000032:analysis; D005841:Gentisates / Q000737:chemistry; D005947:Glucose / Q000032:analysis; D006046:Gold / Q000737:chemistry*; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis; D007211:Indoles / Q000032:analysis; D016014:Linear Models; D053768:Metal Nanoparticles / Q000737:chemistry*; D009994:Osmolar Concentration; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013256:Steroids / Q000032:analysis; D014508:Urea / Q000652:urine; D014527:Uric Acid / Q000652:urine
chemical_list: D002241:Carbohydrates; D005732:Gangliosides; D005841:Gentisates; D007211:Indoles; D013256:Steroids; C025447:sialogangliosides; D014527:Uric Acid; D019343:Citric Acid; D005677:G(M1) Ganglioside; D012965:Sodium Chloride; C067042:indolamine; D006046:Gold; D014508:Urea; D000803:Angiotensin I; D003404:Creatinine; D005947:Glucose; C010925:2,5-dihydroxybenzoic acid; D006854:Hydrocortisone