FIG 2 - uploaded by Ales Fajgelj
Content may be subject to copyright.
Cumulative Sum (CUSUM) Control Chart on the same set of data as for the Shewhart Control Chart above.
Source publication
The application of certified reference materials (CRMs) in analytical chemistry for quality control purposes is well recognized and recommended by a wide range of international, national and professional organizations. However, irrespective of the geographical region or the economic situation in laboratories, current practice in CRM application in...
Similar publications
The occurrence of microplastics (MPs, particles <5 mm) in the environment have raised concerns globally due to their extensive use, slow degradation, low recycling rates, and potential risks to the ecosystem and human health. In the last decade, research on MPs in soil ecosystems has increased but is relatively limited compared to studies on MPs in...
Citations
... The accuracy of analytical procedure was assessed using the precision and the trueness [5,13,14]. In this method, the trueness was calculated using the bias (%) which was defined as: [(mean concentration -certified value)/certified value]*100. ...
This study aims to demonstrate the performance of the inductively coupled plasma mass spectrometry (ICP-MS) following hot plate heating digestion method for marine fauna samples. About 100 to 200 mg of lobster hepatopancreas certified reference materials (CRMs; TORT-3 from National Research Council Canada) in each sample was processed the hot plate heating digestion procedure before analyzing 12 trace metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Cd, Hg and Pb) by ICP-MS. Total 26 CRMs samples in 21 separate batches were analyzed in this study. The recovery of all other studied metals ranged from 90.37 to 106.02%, except Cr. Almost recovery results were less than 100%, thus it confirmed that the contamination of all laboratory apparatuses was not significant. The accuracy results showed that this analytical procedure can be applied to determine some trace metals in marine benthos samples.
Measurements from multiple laboratories have to be related to unifying and traceable reference material in order to be comparable. However, such fundamental reference materials are not available for isotope ratios in atmospheric methane, which led to misinterpretations of combined data sets in the past. We developed a method to produce a suite of synthetic CH4-in-air standard gases that can be used to unify methane isotope ratio measurements of laboratories in the atmospheric monitoring community. Therefore, we calibrated a suite of pure methane gases of different methanogenic origin against international referencing materials that define the VSMOW (Vienna Standard Mean Ocean Water) and VPDB (Vienna Pee Dee Belemnite) isotope scales. The isotope ratios of our pure methane gases range between −320 and +40 ‰ for δ2H–CH4 and between −70 and −40 ‰ for δ13C–CH4, enveloping the isotope ratios of tropospheric methane (about −85 and −47 ‰ for δ2H–CH4 and δ13C–CH4 respectively). Estimated uncertainties, including the full traceability chain, are < 1.5 ‰ and < 0.2 ‰ for δ2H and δ13C calibrations respectively. Aliquots of the calibrated pure methane gases have been diluted with methane-free air to atmospheric methane levels and filled into 5 L glass flasks. The synthetic CH4-in-air standards comprise atmospheric oxygen/nitrogen ratios as well as argon, krypton and nitrous oxide mole fractions to prevent gas-specific measurement artefacts. The resulting synthetic CH4-in-air standards are referred to as JRAS-M16 (Jena Reference Air Set – Methane 2016) and will be available to the atmospheric monitoring community. JRAS-M16 may be used as unifying isotope scale anchor for isotope ratio measurements in atmospheric methane, so that data sets can be merged into a consistent global data frame.
A wide range of nutrients and health-promoting non-nutrient components in mushrooms are a subject of international research, but specific reference materials to facilitate comparison of results among laboratories are lacking. Commercially available food matrix reference materials do not contain components unique to mushrooms (e.g., ergosterol, vitamin D2, chitin, beta-glucans, agaritine, ergothioneine). A Mixed Mushroom Control Material (CM) (homogeneous mixture of 15 types of mushrooms) was prepared and characterized for selected components, including proximates (moisture, protein, ash), total folate, folate vitamers, ergosterol, ergosterol metabolites, vitamin D2 (ergocalciferol), amino acids, total dietary fiber, agaritine, elements (sodium, potassium, phosphorous, magnesium, calcium, iron, copper, manganese, zinc), riboflavin, niacin, thiamin, vitamin B6, pantothenic acid. Subsamples of the CM are available to qualified laboratories from the Food Analysis Laboratory Control Center at Virginia Tech (Blacksburg, VA, USA), to be assayed concurrently with mushroom samples for which food composition data will be published along with results for the CM. Implementation of this CM should facilitate comparison of published data on mushroom composition and health benefit among species, and biodiversity within species by serving as common control sample that allows the separation of analytical variability from true differences in sample composition determined at different laboratories.