ASTM E579-04

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:E579–04
Standard Test Method for
Limit of Detection of Fluorescence of Quinine Sulfate in
1
Solution
This standard is issued under the fixed designation E579; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.5 This standard does not purport to address all of the
safety problems, if any, associated with its use. It is the
1.1 This test method employs the signal-to-noise ratio to
responsibility of the user of this standard to establish appro-
determinethesensitivityofafluorescencemeasuringsystemin
priate safety and health practices and determine the applica-
testing for the limit of detection (LOD) of quinine sulfate
bility of regulatory limitations prior to use.
dihydrate in solution. The results obtained with quinine sulfate
dihydrate in solution are suitable for specifying instrument
2. Referenced Documents
performance on samples having excitation and fluorescence
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2.1 ASTM Standards:
bands wider than 10 nm at or near room temperature.
E578 Test Method for Linearity of Fluorescence Measuring
1.1.1 This test method is not intended to be used as (1)a
Systems
rigorous test of performance of instrumentation, or (2), to
intercompare the quantitative performance of instruments of
3. Summary of Test Method
different design. Intercomparison of the LOD between instru-
3.1 To measure the concentration corresponding to the
ments is commonly expressed as the ratio of the water Raman
LOD, the fluorescence intensity scale and gain on the detector
peakintensitytotheroot-mean-square(rms)noiseasmeasured
are adjusted such that noise observed with pure solvent in the
on a fluorometer using an excitation wavelength of 350 nm
samplecellislargeenoughtomeasure.Thetestsolutionisthen
This test method uses the excitation and emission peak
diluted until readings on both the test solution and pure solvent
wavelengths for quinine sulfate dihydrate in solution, which
canbereadatthesameintensity,scale,andinstrumentsettings.
are approximately 350 nm and 450 nm, respectively.
The concentration corresponding to the limit of detection is
1.2 This test method has been applied to fluorescence-
thatatwhichthenoiseintensity,multipliedbythree,isequalto
measuring systems utilizing non-laser, low-energy excitation
the signal intensity.
sources. There is no assurance that extremely intense illumi-
2 3.2 This test for limit of detection requires an instrument to
nation will not cause photodecomposition of the compound
meet the following conditions: stable, free of extraneous noise,
suggested in this test method. For this reason, it is recom-
electrical pickup, and internal stray light. The sample space
mended that this test method not be indiscriminately employed
must be covered to exclude room light. The instrument should
with high intensity light sources. This test method is not
be operated according to the manufacturer’s recommendations,
intended to determine minimum detectable amounts of other
or, if they are modified, the modifications must be applied
materials. If this test method is extended to employ other
consistently to the test for limit of detection and to the analysis
chemical substances, the user should be aware of the possibil-
for which the test is a requirement, so that levels of perfor-
ity that these other substances may undergo decomposition or
mance are comparable for both. All modifications must be
adsorption onto containers.
included in the report outlined in section 8.
1.3 A typical LOD for conventional fluorometers using this
test method is 1 ng of quinine sulfate per mL.
NOTE 1—To obtain the lowest reading (the best instrumental response)
1.4 The suggested shelf life of a 1 mg/mL stock solution of for the limit of detection of fluorescent material, a number of precautions
must be taken. The quality, condition, and position of the sample cell are
quinine sulfate dihydrate is three months, when stored in the
most important. The cell must be made of fused silica that does not
dark in a stoppered glass bottle.
fluoresce at the excitation wavelength and be free of scratches and marks
that scatter light into the fluorescence detection system. Only spectral
1
grade chemicals and solvents (including water) that do not fluoresce
This test method is under the jurisdiction of ASTM Committee E13 on
Molecular Spectroscopy and Chromatography and is the direct responsibility of
Subcommittee E13.01 on Ultra-Violet, Visible, and Luminescence Spectroscopy.
Current edition approved Feb. 1, 2004. Published March 2004. Originally
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published in 1976. Last previous edition approved in 1998 as E579 – 84 (1998). For referenced
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