= Duncan Thorburn Burns
{c}
{tag=Chemistry author}
= D. T. Burns
{c}
{synonym}
\b[Duncan Thorburn Burns] is an <analytical chemistry> researcher named with <Klaus Danzer> and <Alan Townshend> as preparing the 2002 IUPAC recommendations on recovery terminology. The paper's full byline identifies Burns at Queen's University Belfast; its publisher record abbreviates him as D. T. Burns.<Use of the term "recovery" and "apparent recovery" in analytical procedures by D. T. Burns and others>[printed p. 2201, full-name byline and affiliation; publisher landing-page byline]{ref}
The recommendations distinguish <extraction recovery>, the yield of a separation or preconcentration step, from <apparent recovery>, the ratio of an analytically obtained value to a reference value after <measurement calibration>. These answer different scientific questions: how much <analyte> reaches the measurement stage, and how the final reported result compares with its reference.<Use of the term "recovery" and "apparent recovery" in analytical procedures by D. T. Burns and others>[Abstract, distinction between extraction/preconcentration yield and observed/reference value]{ref}
An original controlled-response example shows why even an apparent recovery of one can conceal a loss. Stipulate a preparation starting with $10\,\mathrm{\mu g}$ of <analyte>, of which $8\,\mathrm{\mu g}$ reaches a final $1\,\mathrm{mL}$ solution. The <extraction recovery> is $8/10=0.80$. Suppose a clean-solvent standard produces one arbitrary signal unit per $\mathrm{\mu g/mL}$, while the final <sample matrix> multiplies the response by $1.25$. The extract then produces ten signal units. A clean-solvent measurement calibration converts that signal to $10\,\mathrm{\mu g/mL}$, equal to the reference concentration for complete recovery:
$$
R_{\rm apparent}=\frac{c_{\rm found}}{c_{\rm reference}}
=\frac{1.25\times8}{10}=1,
\qquad R_{\rm extraction}=0.80.
$$
The stipulated signal enhancement exactly compensates for the extraction loss in this example. Agreement of the final result with the reference does not identify either mechanism separately.
A comparison measurement could introduce equal nominal quantities before extraction, after extraction into a matched blank extract, and into clean solvent, with matched final volumes and instrument settings. Comparing their responses separates preparation losses from a response change caused by the <sample matrix>, under the stated linear-response assumptions. The <analytical matrix effect> article explains the response distinction. Repeating the example with a matrix-matched calibration slope of $1.25$ gives $c_{\rm found}=8\,\mathrm{\mu g/mL}$: the apparent recovery then becomes $0.80$. The number depends on the analytical procedure and its calibration, rather than on extraction yield alone.
Burns and his collaborators' terminology makes those experimental distinctions explicit. A reported recovery value therefore needs its definition, reference and calibration procedure; the percentage by itself leaves the measurement ambiguous.
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