Preparation and Certification of Two New Bulk Welding Fume Reference Materials for Use in Laboratories Undertaking Analysis of Occupational Hygiene Samples

Figures & data

TABLE I. Participants and the Methodologies They Employed in the Certification Exercise

Laboratory	Country	Digestion Method	Acid mixture (temperature)	Analytical Technique
ALS Scandinavia	Sweden	US EPA SW846 Method 3052 - closed vessel microwave assisted digestion^(^24^)	HNO3/HCl/HF (180°C)	ICP- SFMS
Federal Public Service for Employment, Labour, and Social Dialogue (FOD WASO/FPS ELSD)	Belgium	For HSL MSWF-1 samples ISO 15202-2 Annex C hotplate digestion^(^7^)For HSL SSWF-1 samples ISO 15202-2 Annex E hotplate digestion^(^7^)	HNO3/HCl (95°C)HNO3/H2O2/H2SO4 (fuming SO3)	ICP-AES
Flemish Institute for Technological Research (VITO)	Belgium	For HSL MSWF-1 samples NIOSH 7303 - hotblock digestion^(^22^)For HSL SSWF-1 samples EN 13656 - closed vessel microwave assisted digestion^(^23^)	HNO3/HCl (95°C)HNO3/HCl/HF (180°C)	ICP-AES
Health and Safety Laboratory	U.K.	ISO 15202-2 Annex G - closed vessel microwave assisted digestion^(^7^)	HNO3/HCl/HF (180°C)	ICP-AES
Instituto Nacional de Seguridad e Higiene en el Trabajo (INSHT)	Spain	ISO 15202-2 Annex G - closed vessel microwave assisted digestion^(^7^)	HNO3/HCl (180°C)	ICP-AES
Institut National de Recherche et de Sécurité (INRS)	France	ISO 15202-2 Annex G - closed vessel microwave assisted digestion^(^7^)	HNO3/HCl/HF (180°C)	ICP-AES
Kinectrics Inc.	Canada	In-house closed vessel microwave assisted digestion	HNO3/HCl/HF	ICP-AES
Leibniz-Institut für Kristallzüchtung (IKZ)	Germany	In-house closed vessel microwave assisted digestion	HNO3 (250°C)	ICP-AES
National Institute of Occupational Health (NIOH)	Hungary	In-house closed vessel microwave assisted digestion	HNO3/H2O2 (200°C)	ICP-AES
National Institute of Occupational Health (STAMI)	Norway	In-house closed vessel microwave assisted digestion	HNO3/HCl/HF	ICP-AES
National Institute of Occupational Safety and Health (NIOSH)	United States	NIOSH 7300 - hotplate digestion^(^3^)	HNO3/HClO4 (150°C)	ICP-AES
Occupational Safety and Health Administration (OSHA)	United States	OSHA 125G - hotplate digestion^(^4^)	HNO3/H2O2/H2SO4 (fuming SO3)	ICP-AES
Ridsdale & Co. Ltd.	U.K.	In-house hotplate digestion	HNO3/HClO4/H3PO4 (fuming)	ICP-AES

FIGURE 1. Zinc homogeneity results for HSL MSWF-1 together with resultant certified value and expanded uncertainty. The error bars indicate the standard deviation of the mean of triplicate measurements undertaken per bottle unit. The error bar associated with the resultant Zn certified value represents the corresponding expanded uncertainty arising from the certification exercise.

TABLE II. Results of the Zinc Homogeneity Study Conducted on HSL MSWF-1

Analyte	sbb (relative)%	ubb* (relative)%	ubb (relative)%
Zinc	0.25	0.38	0.38

FIGURE 2. Zinc stability results (to date) for HSL MSWF-1 together with resultant certified value and expanded uncertainty. The error bars indicate the standard deviation of the mean of triplicate measurements, over time, from a selected bottle unit. The error bar associated with the resultant Zn certified value represents the corresponding expanded uncertainty arising from the certification exercise.

TABLE III. Statistical Tests Carried Out on Participants’ Data

Statistical test	Comment
Scheffé multiple t-test	All data sets compatible two-by-two?
Cochran test	Outlying variances?
Grubbs, Dixon, and Nalimov tests	Outlying means?
Bartlett test	Variances homogenous?
Scedecor F-test	Differences between data sets statistically significant?
Kolmogorov-Smirnov-Lilliefors test	Normality of the distribution of the means?

TABLE IV. Results of Statistical Tests Carried Out on Accepted Participants’ Data

		Statistical tests
Analyte	Number of data sets accepted	Scheffé	Cochran	Grubbs	Dixon	Nalimov	Bartlett	Snedecor	Kolmogorov Smirnov Lilliefors	Comment
		p = (99% / 95% confidence)
Zinc	9	no	pass	pass	pass	pass /L2	pass	pass	pass	Pooling of data not allowed

FIGURE 3. Certification data for Zinc in HSL MSWF-1 from certification laboratories together with resultant certified value and expanded uncertainty. The error bars indicate the standard deviations of the mean of means from each of the individual laboratories (five Zn replicate aliquots tested from each of two bottles). The error bar associated with the plotted Zn certified value represents the corresponding expanded uncertainty arising from the certification exercise.

TABLE V. Mass Fractions and Uncertainty Components for Zinc in HSL MSWF-1

Analyte	wchar	uchar	ubb	ucombined
	% (m/m)
Zinc	21.69	0.34	0.08	0.35

TABLE VI. Certified Mass Fractions and Expanded Uncertainties of Elements in HSL MSWF-1

	Number of data sets accepted	Mass fraction	Uncertainty
Analyte	n	% (m/m)
Iron	6	42.8	±  0.7
Manganese	10	1.48	±  0.03
Zinc	9	21.7	±  0.9

TABLE VII. Certified Mass Fractions and Expanded Uncertainties of Elements in HSL SSWF-1

	Number of data sets accepted	Mass fraction	Uncertainty
Analyte	n	% (m/m)
Chromium	7	8.4	±  0.4
Iron	9	29.8	±  0.9
Manganese	7	22.9	±  0.5
Nickel	10	3.7	±  0.2

National Institute for Occupational Safety and Health (NIOSH): Method 7303: Elements by ICP (Hotblock HCl/HNO3 Digestion). In Manual of Analytical Methods, 4th ed. Cincinnati, Oh.: NIOSH, 2003.

 Google Scholar

International Organization for Standardization (ISO): Workplace Air—Determination of Metals and Metalloids in Airborne Particulate Matter by Inductively Coupled Plasma Atomic Emission Spectrometry—Part 2: Sample Preparation (ISO 15202-2) [Standard] Geneva: ISO, 20112.

 Google Scholar

Health and Safety Laboratory (HSL): Investigation into the Accuracy and Completeness of Material Safety Data Sheet Information on the Chemical Composition of Welding Fume, IEAS/99/05. Harpur Hill, UK: HSL, 2000.

 Google Scholar

National Institute of Standards and Technology (NIST): Engineering Statistical Handbook. . Available at http://www.itl.nist.gov/div898/handbook/prc/section3/prc31.htm (accessed January 7, 2014).

 Google Scholar

National Institute for Occupational Safety and Health (NIOSH): Method 7300: Elements by ICP. In Manual of Analytical Methods, 4th ed. Cincinnati, Oh.: NIOSH, 2003.

 Google Scholar

Occupational Safety and Health Administration (OSHA): ID-125G: Metal and Metalloid Particulates in Workplace Atmospheres (ICP Analysis). Salt Lake City, Ut.: OSHA, 2002.

 Google Scholar