Detection and Imaging of Chrome Yellow (Lead Chromate) in Latent Prints, Solid Residues, and Minerals by Laser-Desorption-Ionization Mass Spectrometry (LDI-MS).

Title Detection and Imaging of Chrome Yellow (Lead Chromate) in Latent Prints, Solid Residues, and Minerals by Laser-Desorption-Ionization Mass Spectrometry (LDI-MS).
Authors Z. Zheng; J. Pavlov; A.B. Attygalle
Journal J Mass Spectrom
DOI 10.1002/jms.3931
Abstract

In the past, Chrome Yellow (lead chromate, PbCrO4 ), a bright orange-red substance, has been widely used as an inorganic pigment in the production of paints, coatings, and plastics. Herein, we demonstrate that laser desorption/ionization mass spectrometry (LDI-MS) is a powerful tool for the detection of lead chromate in solid residues. In fact, lead chromate in trace amounts is easily detectable by LDI-MS even from residues left as latent prints. For example, a latent print obtained by stamping the exposed laterally cut surface of a pencil over 50?years old on an acetonitrile-moistened paper, was successfully imaged for both lead and chromate using a Synapt G2 HDMS mass spectrometer. After rastering the print with a 355?nm laser beam and recording positive- and negative-ion mass spectra over the range m/z 50-1200, we generated false-color "heat maps" (single-ion images) for (208) Pb(+?) (m/z 207.98) and for Cr2 O6(-?) (m/z 199.85). The heat maps matched closely with the faint visual image of the pencil imprint. Moreover, our results confirmed that lead chromate was used in the pigment coating of old pencils. Evidently, LDI-MS imaging is an efficient procedure to survey for the presence of lead and chromate in minerals and other materials.

Citation Z. Zheng; J. Pavlov; A.B. Attygalle.Detection and Imaging of Chrome Yellow (Lead Chromate) in Latent Prints, Solid Residues, and Minerals by Laser-Desorption-Ionization Mass Spectrometry (LDI-MS).. J Mass Spectrom. 2017. doi:10.1002/jms.3931

Related Elements

Chromium

24 Cr 51.996100000 Chromium

See more Chromium products. Chromium (atomic symbol: Cr, atomic number: 24) is a Block D, Group 6, Period 4 element with an atomic weight of 51.9961. Chromium Bohr ModelThe number of electrons in each of Chromium's shells is 2, 8, 13, 1 and its electron configuration is [Ar] 3d5 4s1. Louis Nicolas Vauquelin first discovered chromium in 1797 and first isolated it the following year. The chromium atom has a radius of 128 pm and a Van der Waals radius of 189 pm. In its elemental form, chromium has a lustrous steel-gray appearance. Elemental ChromiumChromium is the hardest metallic element in the periodic table and the only element that exhibits antiferromagnetic ordering at room temperature, above which it transforms into a paramagnetic solid. The most common source of chromium is chromite ore (FeCr2O4). Due to its various colorful compounds, Chromium was named after the Greek word 'chroma.' meaning color.

Lead

82 Pb 207.200000000 Lead

Lead Bohr ModelSee more Lead products. Lead (atomic symbol: Pb, atomic number: 82) is a Block P, Group 14, Period 6 element with an atomic radius of 207.2. The number of electrons in each of Lead's shells is [2, 8, 18, 32, 18, 4] and its electron configuration is [Xe] 4f14 5d10 6s2 6p2. The lead atom has a radius of 175 pm and a Van der Waals radius of 202 pm. In its elemental form, lead has a metallic gray appearance. Lead occurs naturally as a mixture of four stable isotopes: 204Pb (1.48%), 206Pb (23.6%), 207Pb (22.6%), and 208Pb (52.3%). Elemental LeadLead is obtained mainly from galena (PbS) by a roasting process. Anglesite, cerussite, and minim are other common lead containing minerals. Lead does occur as a free element in nature, but it is rare. It is a dense, soft metal that is very resistant to corrosion and poorly conductive compared to other metals. Its density and low melting point make it useful in applications such as electrolysis and industrial materials.

Related Forms & Applications

Chromates
Publish your research on the American Elements website