International interlaboratory study of forensic ethanol standards

King, Bernard; Lawn, Richard E.

doi:10.1039/a900487d

Cited by 7 publications

(7 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The dichromate oxidation method is considered to be the most accurate and precise method for the determination of ethanol for forensic purposes. The CITAC intercomparison report 4 quotes a precision range of 1.1% for the dichromate oxidation method and 3.2% for GC (headspace) analysis. The same report mentions a maximum possible bias for the dichromate method of 1.2-1.8% (1.4-4.4% for the GC methods).…”

Section: Resultsmentioning

confidence: 99%

“…The samples analysed were two CRMs, LGC 5401 and LGC 5403 (LGC Teddington, Teddington, UK), and three solutions used for an international interlaboratory study initiated by CITAC (Co-operation on International Traceability in Analytical Chemistry) for forensic ethanol determination in water. 4 These solutions had nominal ethanol mass concentrations in water of 50, 80 and 200 mg of ethanol per 100 mL of water. The details of the concentrations and mass fractions of the different solutions analysed are given in Table 1.…”

Section: Experimental Reagents and Standardsmentioning

confidence: 99%

“…7 Table 1 Ethanol mass concentrations and mass fractions for the CITAC solutions, based on their gravimetric preparation. 4…”

Section: Optimisation Of the Experimental Conditionsmentioning

confidence: 99%

“…( 1) and ( 3), the mass fraction of ethanol in the sample X can be expressed by eqn. (4), in which all the variables can be fully described:…”

Section: The Idms Proceduresmentioning

confidence: 99%

See 3 more Smart Citations

High accuracy isotope dilution analysis for the determination of ethanol using gas chromatography-combustion-isotope ratio mass spectrometry

Briche¹,

Hernández²,

O’Connor³

et al. 2000

Analyst

View full text Add to dashboard Cite

A procedure was established for the determination of ethanol in water samples by isotope dilution analysis. After spiking the sample with labelled [13C2]ethanol, it was analysed by gas chromatography-combustion-isotope ratio mass spectrometry. Results are reported for two certified reference materials and also ethanol solutions prepared for a CITAC (Co-operation on International Traceability in Analytical Chemistry) interlaboratory comparison. The certified reference materials were certified using the dichromate titration method at nominal levels of 80 and 200 mg per 100 mL. The CITAC solutions were prepared gravimetrically at nominal levels of 50, 80 and 200 mg per 100 mL. The results of the analysis agree well to within 0.5% of the gravimetric values of the different samples. The relative expanded standard uncertainties (with a coverage factor equal to 2) associated with the results varied between 0.18 and 0.37%, a range that encompassed the gravimetric values for the different samples. A complete uncertainty budget was also drawn up so that the different contributions could be identified and quantified. The main contributions were due to variations in the measured isotope amount ratios and a 'between' blend component introduced to quantify the contribution of factors such as the degree of matching of the isotope amount ratios between standards and samples used in the isotope dilution analysis.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Experimental Reagents and Standardsmentioning

confidence: 99%

“…7 Table 1 Ethanol mass concentrations and mass fractions for the CITAC solutions, based on their gravimetric preparation. 4…”

Section: Optimisation Of the Experimental Conditionsmentioning

confidence: 99%

“…( 1) and ( 3), the mass fraction of ethanol in the sample X can be expressed by eqn. (4), in which all the variables can be fully described:…”

Section: The Idms Proceduresmentioning

confidence: 99%

See 2 more Smart Citations

High accuracy isotope dilution analysis for the determination of ethanol using gas chromatography-combustion-isotope ratio mass spectrometry

Briche¹,

Hernández²,

O’Connor³

et al. 2000

Analyst

View full text Add to dashboard Cite

show abstract

“…We will assume the purity (P) to be 0.995 with a Type B standard uncertainty of 0.002 determined from the certificate of analysis. We further assume that the density (D) of the solution is 0.997 g/ml (OIML, King and Lawn, 1999) with a Type B standard uncertainty of 0.00054 g/ml (King and Lawn, 1999), determined from the certificate of analysis from the manufacturer of a density meter. For both the purity and the density we will assume the uniform distribution in order to estimate their standard uncertainties.…”

Section: Dealing With Measurement Biasmentioning

confidence: 99%

Measurement Uncertainty in Forensic Toxicology: Its Estimation, Reporting and Interpretation

Gullberg¹

2012

Toxicity and Drug Testing

View full text Add to dashboard Cite

A Monte Carlo approach for estimating measurement uncertainty using standard spreadsheet software

Chew

Walczyk

2012

Anal Bioanal Chem

View full text Add to dashboard Cite

Despite the importance of stating the measurement uncertainty in chemical analysis, concepts are still not widely applied by the broader scientific community. The Guide to the expression of uncertainty in measurement approves the use of both the partial derivative approach and the Monte Carlo approach. There are two limitations to the partial derivative approach. Firstly, it involves the computation of first-order derivatives of each component of the output quantity. This requires some mathematical skills and can be tedious if the mathematical model is complex. Secondly, it is not able to predict the probability distribution of the output quantity accurately if the input quantities are not normally distributed. Knowledge of the probability distribution is essential to determine the coverage interval. The Monte Carlo approach performs random sampling from probability distributions of the input quantities; hence, there is no need to compute first-order derivatives. In addition, it gives the probability density function of the output quantity as the end result, from which the coverage interval can be determined. Here we demonstrate how the Monte Carlo approach can be easily implemented to estimate measurement uncertainty using a standard spreadsheet software program such as Microsoft Excel. It is our aim to provide the analytical community with a tool to estimate measurement uncertainty using software that is already widely available and that is so simple to apply that it can even be used by students with basic computer skills and minimal mathematical knowledge.

show abstract

International interlaboratory study of forensic ethanol standards

Cited by 7 publications

References 4 publications

High accuracy isotope dilution analysis for the determination of ethanol using gas chromatography-combustion-isotope ratio mass spectrometry

High accuracy isotope dilution analysis for the determination of ethanol using gas chromatography-combustion-isotope ratio mass spectrometry

Measurement Uncertainty in Forensic Toxicology: Its Estimation, Reporting and Interpretation

A Monte Carlo approach for estimating measurement uncertainty using standard spreadsheet software

Contact Info

Product

Resources

About