Talk:Detection limit

message: The current description of detection limit is fundamentally wrong in the sense that the detection limit is not the level at which the detection decision is taken. The detection decision is a one-sided test (Ho: analyte is absent) that only considers false positives. Assume for example that a risk of 5% is accepted to report a positive when in fact the analye is absent. Further assume that the distribution is Gaussian, as is done in the figure. Then the decision should be taken at about 1.65 sigma. This is called the critical level or decision limit. The detection limit is the level that will lead to false non-detects with a certain probability (say 5%) if the decision is taken at the critical level. Assuming two identical Gaussian distributions (the second one for Ha: analyte present at this level) leads to a detection limit of about 3.30 sigma. Klaas Faber 80.126.235.235 (talk) 16:13, 24 January 2008 (UTC)
thread_title: Incorrect definition

message: I suggest that Detection limit and Detection Limits be merged. Biscuittin 18:32, 5 July 2007 (UTC)
replies: text: Support Added templates.  --Kkmurray 14:51, 19 August 2007 (UTC)
thread_title: Merge proposal

message: I don't know what the material at the end of this article is or means.  Perhaps the material at the end should just be removed?  What I am referring to, is the list of analytical methods.  There doesn't really seem to be any information related to detection limit in that section.
--Chris (talk) 22:20, 10 January 2008 (UTC)
replies: text: Agreed - I removed it just now.  It still contained no data a year after the cleanup tag was added, and (as a list) it was inherently unmaintainable anyway. -- Jaeger5432 | Talk 17:57, 3 September 2008 (UTC)
thread_title: The Material at the end

message: The LOQ may be more common in research labs, but a more general approach to the sticky issue of reporting results as they near the MDL is the Method Reporting Limit.  Method Reporting Limits (MRL) are generally about ten times the MDL.  There is a formula for computing the MRL based on the MDL for EPA compliance labs, but I don't recall exactly what it is.  Reporting results near the MDL aren't a sticky issue just because of the LOQ, but also because the claimed uncertainty for a method begins to break down at low levels.  If a method claims +/-10% uncertainty, then in the most simple terms what that really means is +/-10% or +/- the MDL, whichever is greater.  Of course, +/- the MDL is probably too generous even if the result is slightly above the LOQ, but the problems with the relationship between the MDL and the claimed uncertainty will normally continue well above the LOQ.
For example, a hypothetical method has an MDL of 1ppm, a claimed uncertainty of +/-10%, and an LOQ of 5ppm.  I get a result of 8ppm.  What is the uncertainty for that measurement?  Common sense tells you that the resolution of the reported results should never be better than the MDL, so I can't say that the range is 7.2ppm - 8.8ppm, since I know I can't measure fractions of a ppm.  At best it can only be 8ppm +/-1ppm, but 1ppm is more than 10% of 8ppm.
That may all seem very technical, but arguments over uncertainty will inevitably occur if MRL's are not in place.  An MRL of 10ppm for the above example would quiet most of these arguments, because the uncertainty is at least equal to the MDL.
--Rataan (talk) 17:41, 1 August 2008 (UTC)
thread_title:  Method Reporting Limit 

message: The cited article Gary L. Long & J.D Winefordner; Analytical Chemistry, 55(7), 713A - 724A, (1983) is not to be found in Analyt. Chem.Silin2005 (talk) 13:27, 8 August 2008 (UTC)
thread_title:  False reference number 3

message: Gll1955 (talk) 01:58, 11 April 2010 (UTC)
thread_title:  Incorrect use of IUPAC and ACS definitions 

message: Much of this article (espcially the Instrument detection limit section) appears to be copy-pasted from here: http://www.chem.agilent.com/Library/technicaloverviews/Public/5990-7651EN.pdf
Proper references/quotations/paraphasing should be included.Piyrwq (talk) 17:21, 8 November 2011 (UTC)
thread_title:  Improper Referenceing? 

message: Lloyd A. Currie, Limits for Qualitative Detection and Quantitative Determination: Application to Radiochemistry, Anal. Chem. 40, 586-593 (1968)</ref> obtained from http://www.docstoc.com/docs/863579/Lloyd-A-Currie-Limits-for-Qualitative-Detection-an-Quantitative-Determination-Application-to-Radiochemistry-REPRINT
"Until Lloyd Currie’s paper Limits for Qualitative Detection and Quantitative Determination: Application to Radiochemistry
was published, there was enough inconsistency in the definition of “detection limit” to conceal a great deal of disagreement.  In just over seven pages, this tightly written communication established a high level of uniformity in answering these questions.
The paper contains fundamental information that has made it influential far beyond its size, and it is rich enough to be discussed actively in e-mail news groups over 30 years later.  This is surely one of the most often cited publications in analytical chemistry"http://www.docstoc.com/docs/7181537/Limits-for-Qualitative-Detection-and-Quantitative-Determination
Until Lloyd defined the terms it was a mess.
Bestshot (talk) 21:03, 4 February 2012 (UTC)
thread_title:  Reference to Lloyd A. Currie's paper is a must! 

message: In Urdu 103.255.7.22 (talk) 05:10, 19 September 2022 (UTC)
thread_title:  Limit of detection 

message: Specifically in the section "Significance in analytical chemistry" 
* "analytical sensistivity" links to the article about Specificity and Sensitivity which IMO is not relevant
* "calibration plot" links to something about machine learning which also seems to be irrelevant (I don't know anything about that topic)
Unfortunately I do not if there is a better wikipedia link (obviously if I did know I wouldn't need to be reading the article) 82.22.157.112 (talk) 13:56, 15 December 2022 (UTC)
thread_title:  Some wiki links don't support the text they're embedded in