Organic salt NEDC (N-naphthylethylenediamine dihydrochloride) assisted laser desorption ionization mass spectrometry for identification of metal ions in real samples.
The significance of metals in life and their epidemiological effects necessitate the development of a direct, efficient, and rapid method of analysis. The matrix assisted laser desorption/ionization technique is on the horns of a dilemma of metal analysis as the conventional matrixes have high background in the low mass range. An organic salt, NEDC (N-naphthylethylenediamine dihydrochloride), is applied as a matrix for identification of metal ions in the negative ion mode in the present work. Sixteen metal ions, Ba(2+), Ca(2+), Cd(2+), Ce(3+), Co(2+), Cu(2+), Fe(3+), Hg(2+), K(+), Mg(2+), Mn(2+), Na(+), Ni(2+), Pb(2+), Sn(2+) and Zn(2+), in the form of their chloride-adducted clusters were systematically tested. Mass spectra can provide unambiguous identification through accurate mass-to-charge ratios and characteristic isotope patterns. Compared to ruthenium ICP standard solution, tris(2,2'-bipyridyl)dichlororuthenium(ii) (C30H24N6Cl2Ru) can form organometallic chloride adducts to discriminate from the inorganic ruthenium by this method. After evaluating the sensitivity for Ca, Cu, Mg, Mn, Pb and Zn and plotting their quantitation curves of signal intensity versus concentration, we determined magnesium concentration in lake water quantitatively to be 5.42 mg L(-1) using the standard addition method. There is no significant difference from the result obtained with ICP-OES, 5.8 mg L(-1). Human urine and blood were also detected to ascertain the multi-metal analysis ability of this strategy in complex samples. At last, we explored its applicability to tissue slice and visualized sodium and potassium distribution by mass spectrometry imaging in the normal Kunming mouse brain.
Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China. znie@iccas.ac.cn.
Jian
J
Hou
Suming
S
Chen
Ning
N
Zhang
Huihui
H
Liu
Jianing
J
Wang
Qing
Q
He
Jiyun
J
Wang
Shaoxiang
S
Xiong
Zongxiu
Z
Nie
D000328:Adult; D000818:Animals; D001923:Brain Chemistry; D002412:Cations / Q000032:analysis / Q000097:blood / Q000652:urine; D002712:Chlorides / Q000737:chemistry; D005029:Ethylenediamines / Q000737:chemistry*; D005260:Female; D006801:Humans; D060106:Lakes / Q000032:analysis*; D008670:Metals / Q000032:analysis* / Q000097:blood* / Q000652:urine; D051379:Mice; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D055815:Young Adult
D002412:Cations; D002712:Chlorides; D005029:Ethylenediamines; D008670:Metals; C008588:N-(1-naphthyl)ethylenediamine