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Surface and Microanalysis Science Division (Chemical Science and Technology Laboratory)

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Glossary of Terminology and Acronyms

techniques vs. methods	traceability	APM
delta notation	Standards	TOT
IRMS	GC/MS	TOR
IAEA	CSTL	CF-IRMS
TOA	SMSD	VPDB
PM	NGS	VOC
SRM	metrology
STD	CRM
XPS	RM
	IM

SMSD, CSTL	Tthe Surface and Microanalysis Science Division (SMSD) is within the Chemical Science Technology Laboratory (CSTL). CSTL is one of seven technical measurement laboratories within NIST.

delta notation	A system to express isotopic composition of a sample relative to a standard artifact. The delta value is dimensionless, and is commonly multipled by 1000 and expressed as per mill (analogous to percent).
GC/MS	Gas chromatography/mass spectrometry
IAEA	International Atomic Energy Agency, headquartered in Vienna, Austria.
IRMS, CF-IRMS	Isotope ratio mass spectrometry (IRMS). When combined with GC and a continuous flow (CF) interface, the technique is known as CF-IRMS.
metrology	A general term for the total system, or framework, of measurements and supporting services, and the science behind these measurements and services, that enables traceability to primary standards (hence, enabling accurate measurements with known uncertainties).
NGS	Natural Gas Standard, originally developed by the IAEA and distributed by Chevron. NIST distributed these standard materials (as IMs) from 1992 until 2003, when they were upgraded to RMs (RM 8559, 8560, and 8561).
PM, APM, PM2.5	Particulate matter (PM); airborne particulate matter (APM); fine particulate matter (PM2.5) having an aerodynamic diameter less than 2.5 micrometers.

SRM, CRM, RM, IM	Standard Reference Material (SRM) is a certified reference material (CRM) developed and certified by NIST under strict protocols. An uncertified reference material (RM) has property values that are sufficiently homogeneous and well established to be used for the calibration of an apparatus, the assessment of an examination procedure, or for assigning values to materials [Adapted from VIM:1993-6.13 (3)]. The value assignment and uncertainty of an RM may change as the material is characterized further. An intercomparison material (IM) has no value assignment, but is useful to intercompare measurement techniques and methods, especially across laboratories.
Standards	A very broad term. Here, the term signifies standard materials (SRMs, CRMs, RMs, IMs), reference data (SRD, STD), and calibrations.
STD	Standard Test Data. Like NIST's Standard Reference Materials (SRMs), Standard Test Data are used to assure the quality of the chemical measurement process. While SRMs are used to assess the complete chemical measurement process from sample preparation/measurement through data evaluation, Standard Test Data are used to assess the quality of the data evaluation domain; in particular, computer-based data-analysis procedures that convert instrument responses to relevant chemical information.
techniques vs. methods	While the distinction is sometimes blurred, a measurement technique emanates from a particular detection technology or principle (e.g., IRMS), whereas a measurement method (where hardware configuration and physico-chemical procedures are specified for a technique) is specifically developed to quantify a particular analyte.
TOA, TOT, TOR	TOT (Thermal Optical Transmittance) and TOR (Thermal Optical Reflectance) are related -- but distinct -- TOA (Thermal Optical Analysis) techniques. In both, the change in optical absorbance of a sample during thermal heating is monitored either by transmittance (through the sample) or by reflectance (off the sample surface) of IR monochromatic light. Various methods have been developed for each technique.
traceability	The property of the result of a measurement or the value of a measurement standard whereby it can be related to stated references, usually national or international measurement standards, through an unbroken chain of comparisons all having stated uncertainties [VIM:1993, 6.10 (3)]. See NIST policy statement.
XPS	X-ray Photoelectron Spectroscopy. Related closely to AES and ESCA. The technique is based on the photoelectric effect, and is surface specific due to the short range of the photoelectrons that are excited from the solid. The energy of the photoelectrons are characteristic of each element. The shape of each peak and the binding energy can be slightly altered by the chemical state of the emitting atom. Hence XPS can provide chemical bonding information as well as elemental characteristics of the surface.
VPDB	Vienna-Pee Dee Belemnite (VPDB) is the scale for reporting C-13 and O-18 relative abundances via the delta notation. The VPDB scale is defined explicitly through NBS-19 calcite (RM 8544).
VOC	Volatile Organic Carbon.

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