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The Museum Conservation Institute - Facilities


Proteomics, MS/MS, SEM, ICP-MS, XRF, pXRF, micro-XRF, XRD, Raman, portable-Raman, FTIR, Gas Chromatography, Stable Isotope Mass Spectrometry, Element Analyzer, Infrared Imaging, Multi-Spectral Imaging, 3-D Scanning, Optical Microscopy, 3-D microscopy, Thermal Analysis, Light Fading, Radiography, Materials Aging


Analytical Technique Instrumentation Application(s)
Proteomics Orbitrap Velos
LTQ Orbitrap Velos
Used for the large-scale study of protein structure and function including chemical characterization and quantitation of biological and chemical samples. (available at MCI in early 2011)
Organic MS/MS Thermo LCQ-DUO
Thermo LCQ-DUO

Instrument 1 has a Beckman Coulter Capillary Electrophoresis (CE) front end and is used for biological aging projects.

Instrument 2 has a IonSense DART (Direct Analysis Real Time) peripheral used for surface analysis of organic compounds.

SEM
Scanning Electron Microscopy,

SEM-EDS
SEM-Energy Dispersive Spectroscopy,

SEM-µXRF
SEM-micro X-ray Fluorescence Spectrometer
Hitachi S-3700N Variable Pressure Scanning Electron Microscope w/Bruker EDS and IXRF fX series micro-XRF
LTQ Orbitrap Velos
Used for low- and high-magnification imaging at variable pressure (<1–270 Pa). The sample chamber can accommodate objects up to 30 cm in diameter and 8 cm in height. This instrument is capable of imaging and analyzing intact objects non-destructively, without the need to sample, embed, polish and coat as in traditional SEM-EDS. The EDS and µXRF are used for inorganic elemental mapping and analysis of samples. Depending on the nature and preparation of the sample, EDS analyses can be qualitative or fully quantitative, with limits of detection possible down to 0.5%; in some cases detection limits of 10 ppm are achievable with the µXRF. SEM-EDS elemental map

Figure: SEM-EDS elemental map of oxygen (orange), carbon (green) and phosphorus (purple) in degraded cellulose acetate. The crystals are enriched in phosphorus relative to the surrounding area.

TOF-ICP-MS
Time-of Flight Inductively Coupled Plasma-Mass Spectrometry

LA-ICP-MS
Laser Ablation Inductively Coupled Plasma-Mass Spectrometry
GBC Optimass TOF-ICP-MS
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New Wave 266 nm laser ablation system
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Able to measure most elements on the periodic table. ICP-MS is especially useful for analysis of inorganic materials, such as metal alloys, glass, ceramics, pigments, and minerals.

Samples can be introduced to the spectrometer as a solution or in solid form via laser ablation, which is minimally invasive to the object.

Detection limits range from %-level to ppb or ppt range for many elements.

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Figure: Laser Ablation craters after the analysis of a glass bead. The total area impacted is ca. 0.08 mm diameter.

ED-XRF
Energy Dispersive X-ray Fluorescence Spectrometer
ElvaTech, ElvaX ED-XRF
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Benchtop XRF instrument used for non-destructive elemental analysis in the laboratory or in the collection facilities. XRF is especially useful for identifying inorganic compounds such as metal alloys, glass, ceramics and pigments.
p-XRF
Portable X-ray Fluorescence Spectrometer
(Two instruments available)
Bruker Tracer III-V ED-XRF
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Portable handheld XRF instrument used for non-destructive elemental analysis; p-XRF is especially useful for identifying inorganic compounds, such as metal alloys, glass, ceramics and pigments.

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Figure: Plot of zirconium and strontium concentrations (ppm) for 2154 obsidian artifacts analyzed by portable XRF. Each cluster corresponds to a specific geologic outcrop.

micro-XRF Bruker ARTAX micro XRF
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Micro-XRF instrument used for non-destructive elemental analysis and generating high resolution elemental maps

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Figure: Elemental map (ca. 40 x 15 mm) of chromium distribution in a lunar gabbro meteorite. Warmer colors equal higher concentration, i.e., red is olivine.

XRD
X-ray Diffraction
Rigaku D/MAX-RAPID XRD
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Used for identification of crystalline structure in inorganic materials; especially useful for pigments, minerals, and corrosion products.

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Figure: Typical XRD pattern for dolomite.

Raman Spectroscopy:
FT-Raman & Dispersive Raman
Thermo Nicolet Almega XR Dispersive Raman Spectrometer
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Thermo FT Raman image072

Raman is used to provide qualitative and quantitative information on organic and inorganic molecules in a given sample matrix. Raman is particularly useful for examining polymers, monomers, and other modern materials found in museums, as well as proteinaceous and keratinaceous materials, pigments, and some corrosion products.

Spectra are very specific; chemical identifications can be performed by using search algorithms in digital databases.

Analyses are non-destructive; little or no sample preparation is required.

Fiber optic lines can be used for analyses ‘outside of the box’.

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Figure: Typical Raman spectrum for cellulose acetate.

Portable Raman B&W TEK MiniRam II
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Portable Raman system with a 10 cm-1 spectral resolution through the Raman shift range of 175–3100 cm-1, with an integrated stabilized 785nm excitation laser. By using the fibre-coupled sampling probe, users can collect Raman spectra of solids or liquids in the field.
FTIR
Fourier Transform Infrared
Thermo Nicolet 6700 Fourier Transform Infrared Spectrometer with Centaurus microscope and Golden Gate micro Attenuated Total Reflectance (ATR) accessory.
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FTIR used to produce a "fingerprint" spectrum of different chemical compounds within objects. FTIR is useful for characterizing organic molecules, such as coatings, adhesives, and paint binders, and some inorganic molecules.

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Figure: Comparison of FTIR spectra. Top: a palmitic acid standard; Bottom: sample from an ethnographic object.

GC
Gas Chromatography

GC/MS
Gas Chromatography Mass Spectrometry

Py-GC/MS
Pyrolysis Gas Chromatography Mass Spectrometry

HS-GC/MS
Headspace Gas Chromatography Mass Spectrometry
Instrument 1-Agilent 6890N GC with Agilent 5975 quadrupole mass spectrometer, CDS Pyroprobe 5150 pyrolyzer, & Agilent 7694E headspace sampler
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Instrument 2-Agilent 5890 GC with ECD and NPD image086

GC and GC/MS are instrumental technique in which complex mixtures of chemicals may be separated, identified and quantified. The technique first vaporizes dissolved samples or derivatives (chemically modified samples), into gases and then separates according to their volatility (and polarity). In MS each gas is then bombarded with electrons so that ion fragments are formed. These ions are separated and filtered according to the fragment masses and counted. Interpretation of the resulting mass fragmentation patterns provides the identification of the gases and ultimately the chemical makeup of the sample.

Py-GC/MS is used to provide rapid analysis of solvent-insoluble samples, but is particularly useful analysis of intractable and nonvolatile macromolecular complexes, i.e., polymers, soils, sediments, and hair.

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Figure: Pyrogram of Flo-texx, a product used as a mounting medium in microscopy. Large peak in the center is methyl methacrylate; the large peak on the right is n-butyl methacrylate.

IRMS
Isotope Ratio Mass Spectrometry
Instrument-1 Thermo Delta V Advantage with Conflo-IV Interface, and Costech EA image087

Instrument-2 Thermo Dual inlet Delta V Advantage with Conflo-IV Interface, GasBench II with GC PAL autosampler, and Thermo TC/EA image090

Used for high-precision isotope ratio studies of carbon, nitrogen, oxygen, hydrogen, and sulfur (C, N, O, H, and S).

C, N, O, H, and S naturally occur as two or more stable (non-radioactive) isotopes. The stable isotope composition of organic and inorganic substances can be used to trace the pathways and forms that these key elements take as they are transferred and cycled within biological and geochemical systems. Measurements of stable isotope ratios in soils and plant samples are used to reconstruct past climates and vegetation, evaluate physiological responses of wild and domesticated plants (and animals), characterize energy and material transfers and transformations among plant, animal, and microbial components of ecosystems, and understand atmosphere-biosphere interactions. Stable isotopes record information on biological and physical processes operating across space and time, and thus are useful in integrative studies that span disciplines and levels of biological organization. Rapid and precise stable isotope analysis of solid, liquid, and gaseous materials is fundamental to many studies in physiology, ecology, hydrology, and earth and atmospheric sciences.

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Figure: Chromatogram of N2 and CO2 isotopes in an organic standard.

http://si.edu/mci/irms/index.htm

EA
Element Analyzer
Costech ECS 4010 CHNOS Element Analyzer
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Can be used as a stand-alone instrument to measure bulk carbon, nitrogen, oxygen, hydrogen, and sulfur in a given sample, or as a sampling system for IRMS that does not contaminate the sample with atmospheric nitrogen and oxygen, especially working at very low concentrations.

http://si.edu/mci/irms/index.htm

Infrared Reflectography image094

Non-destructive technique used to examine paintings and artworks and detect hidden details under the upper layers such as added paint, underdrawings, and hidden signatures or watermarks.

(Instrument purchase courtesy of Smithsonian Women’s Committee Grant)

http://si.edu/mci/ImagingStudio/Multispectral Imaging.html

Multi-Spectral Imaging Surface Optics SOC710 Camera
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Used for imaging in the 400 to 1000 nanometer spectral range. Lenses are interchangeable and the camera can be fixed to a tripod or to any microscope for biological scanning.
3-D Scanning Breuckmann GmbH triTOS-HE structured light scanner
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Used for high-resolution, digital, 3-dimensional documentation projects.

By viewing the data files with 3D graphic software, it is possible to view and manipulate the 3D graphic models on a computer screen, make virtual measurements, and create virtual lighting to best study the surfaces of the object. The 3D data also can be used to make replicas in the positive or negative at any scale in almost any material by computer numerical controlled milling (CNC) or rapid prototyping.

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Figure: 3-dimensional representation of a 2nd century B.C.E. bronze torso recovered from the Vani site, Republic of Georgia.

http://si.edu/mci/ImagingStudio/3D%20Scanning.html

Optical Microscopy Multiple microscopes at MCI
image098 http://si.edu/mci/ImagingStudio/Microscopy.html

Used to document, describe, analyze, and identify objects; provides unique information about the structure and state of preservation of objects and the identity of their component materials.

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3-D Microscopy image099

Used for 3-dimensional imaging analysis; provides unique information about the structure and state of preservation of objects and the identity of their component materials.

(Instrument purchase courtesy of Smithsonian Women’s Committee Grant)

http://si.edu/mci/ImagingStudio/Microscopy.html

DSC
Differential Scanning Calorimetry

DTA
Differential Thermal Analysis

TGA
Thermo-Gravimetric Analysis
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DSC and DTA are used to study phase transitions, such glass transition melts and other thermal transitions.

TGA is used to examine the characteristics of materials such as polymers, to determine degradation temperatures, absorbed moisture content of materials, the level of inorganic and organic components in materials, decomposition points of explosives, and solvent residues.

Micro-Scale Color Fading Tester GBandFadeometer

Used to determine light-fastness data for museum objects.

The device consists of a reflectance spectrophotometer coupled to an accelerated light fading micro-tester. The instrument uses fiber optics for delivering light to the sample. Two advantages of this technique are small spot size (< 0.4 mm) and short testing time (1-2 minutes).

Digital Radiography GE Inspection Technologies Computed Radiography Scanner—Pegasus CR 50P
image104 Digital Radiograph of a Nautilus shell

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Used for the structural examination of art and artifacts. For art works, it helps to reveal losses, replacements, and methods of construction that may not be visible to the naked eye.

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Weather-ometer Atlas Ci4000 Xenon Weather-Ometer
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The ci4000 is calibrated to run samples at museum conditions of temperature and relative humidity while exposing samples to accelerated light conditions, in order to assess the likelihood of degradation and deterioration during extended periods of museum gallery display. Other more extreme temperatures and humidity conditions can also be created and maintained; exposure to Ultra violet light or to infra red heating can be included or excluded. Particularly useful to gauge the length of gallery life for organic materials sensitive to light: natural dyes, plastic films, textile fibers, papers, feathers, leathers.