Recommendations for Fluorescence Instrument Qualification: The New ASTM Standard Guide

Abstract

Aimed at improving quality assurance and quantitation for modern fluorescence techniques, ASTM International (ASTM) is about to release a Standard Guide for Fluorescence, reviewed here. The guide's main focus is on steady state fluorometry, for which available standards and instrument characterization procedures are discussed along with their purpose, suitability, and general instructions for use. These include the most relevant instrument properties needing qualification, such as linearity and spectral responsivity of the detection system, spectral irradiance reaching the sample, wavelength accuracy, sensitivity or limit of detection for an analyte, and day-to-day performance verification. With proper consideration of method-inherent requirements and limitations, many of these procedures and standards can be adapted to other fluorescence techniques. In addition, procedures for the determination of other relevant fluorometric quantities including fluorescence quantum yields and fluorescence lifetimes are briefly introduced. The guide is a clear and concise reference geared for users of fluorescence instrumentation at all levels of experience and is intended to aid in the ongoing standardization of fluorescence measurements.

Moving towards a technical specification for fluorescence excitation-emission mapping and absorbance analysis of colored dissolved organic matter

“…Three recent publications from NIST researchers have particular significance for EEM correction, including a reference to the recently released ASTM standard guide (E2719) for fluorescence calibration and correction [9], a reference to CDOM EEMs and all aspects of instrument and IFE correction, [2] and a reference to the validation of the Fluorolog ® as the true accurate fluorometer for its use in generating and validating a series of Standard Reference Materials [7]. Furthermore, a recent paper has been accepted outlining the results of a major international interlaboratory comparison for CDOM IHSS standard samples; this study was headed by researchers and the United States Geological Survey (USGS), and was the focused outcome of a recent 2008 Chapman conference sponsored by the American Geophysical Union [8].…”

“…The key issues surrounding analysis of the EEMs with PARAFAC are the importance of reproducible and accurate spectral and instrumental correction of the data [1,2,6,7,9]. A major required spectral-correction method discussed below involves the coordinated evaluation of the absorbance spectrum of the sample in order to correct for the optical processes known as "inner-filter effects" (IFEs) [10][11][12][13].…”

Calibration, standardization, and quantitative analysis of multidimensional fluorescence (MDF) measurements on complex mixtures (IUPAC Technical Report)

“…The excitation and the emission sides of the instrument must be spectrally calibrated according to standard methods [12,[16][17][18][20][21][22][23]. .…”

“…Since the electronic output from the detector is dependent on the experimental and instrumental circumstances, fluorescence intensities are routinely reported in arbitrary units (a.u.). The 2009 ASTM standard [15,16] and a recent IUPAC technical report [13] cover many of these issues in detail.…”

“…To date, no such multi-fluorophore standards exist, and consequently both excitation and emission should be calibrated independently using conventional procedures. The reader is directed elsewhere for more detailed discussion of the aspects of standard spectral correction [12,[16][17][18][19][20][21][22][23].…”