Antimony in Polyethylene Terephthalate-Bottled Beverages: The Migration Puzzle.

A novel strategy to assess the main variables that potentially affect the migration of antimony from PET bottles to beverages, including mineral waters and juices, is herein proposed. In a preliminary step, an LC-ICP-MS method previously used for water analysis was optimized to correct identify Sb species present in the studied matrices using HRMS. Subsequently, the influence of temperature and storage time up to 30 days on Sb migration from PET bottles into peach and pineapple juices of the same brand was studied. Storing PET bottled drinks at elevated temperatures (i.e., in a hot car or in summer) can cause antimony migration to exceed the limits allowed in the EU or USA. Because the behavior observed differed from the results reported for Sb migration in mineral waters, a second approach was proposed: three mineral water and two juice samples were kept in different PET containers and stored at an elevated temperature (up to 60 °C) to understand the role of the PET type and matrix simultaneously. This study demonstrated that both matrix characteristics and type of PET bottle greatly influence antimony leaching, highlighting the need to consider these variables together when conducting migration experiments. The obtained results can be helpful for developing future legislation concerning migration of pollutants from packing to food commodities.

Inter-rater reliability assessment for the new-born screening quality assurance.

Introduction: To ensure the quality of the new-born screening (NBS), our laboratory reviewed the analytical procedure to detect subjective steps that may represent a risk to the patient. Two subjective activities were identified in the extra-analytical phases: the classification of dried blood spots (DBS) according to their quality and the assignment of haemoglobin patterns. To keep these activities under control, inter-rater studies were implemented. This study aimed to evaluate the inter-rater reliability and the effectiveness of the measures taken to improve the agreement between observers, to assure NBS results' quality. Materials and methods: Dried blood spots specimens were used for the inter-rater studies. Ten studies were performed to assess DBS quality classification, and four to assess the assignment of haemoglobin patterns. Krippendorff's alpha test was used to estimate inter-rater reliability. Causes were investigated when alpha values were below 0.80. Results: For both activities, the reliability obtained in the first studies was inadequate. After investigation, we detected that the criterion to classify a DBS as scant was not consolidated, and also a lack of consensus on whether or not to report Bart's haemoglobin depending on its percentage. Alpha estimates became higher once the training was reinforced and a consensus about the appropriate criteria to be applied was reached. Conclusion: Inter-rater reliability assessment helped us to ensure the quality of subjective activities that could add variability to NBS results. Furthermore, the evolution of the alpha value over time allowed us to verify the effectiveness of the measures adopted.

External quality assessment in the absence of proficiency testing: A split-sample testing program experience.

In the field of laboratory medicine, proficiency testing is a vehicle used to improve the reliability of reported results. When proficiency tests are unavailable for a given analyte, an alternative approach is required to ensure adherence to the International Organization for Standardization (ISO) 15189:2012 standard. In this study, we report the results of a split-sample testing program performed as an alternative to a formal PT. This testing method was based on recommendations provided in the Clinical and Laboratory Standards Institute (CLSI) QMS24 guideline. Two different laboratories measured, in duplicate, the heparan sulfate concentration in five samples using ultra-performance liquid chromatography and tandem mass spectrometry. The data analysis to determine the criterion used for the comparability assessment between the two laboratories was based on Appendix E of the QMS24 guideline. Mean interlaboratory differences fell within the maximum allowable differences calculated from the application of the QMS24 guideline, indicating that the results obtained by the two laboratories were comparable across the concentrations tested. Application of the QMS24 split-sample testing procedure allows laboratories to objectively assess test results, thus providing the evidence needed to face an accreditation audit with confidence. However, due to the limitations of statistical analyses in small samples (participants and/or materials), laboratory specialists should assess whether the maximum allowable differences obtained are suitable for the intended use, and make adjustments if necessary.

Analytical performance specifications based on the state-of-the-art for the newborn screening.

INTRODUCTION: For the measurands of the newborn screening (NBS), there are no analytical performance specifications (APS) available based on the Milan consensus Models. The objective is to provide total error (TE) APS based on the state-of-the-art (SOTA) for the NBS. MATERIAL AND METHODS: 23,662 results were collected from the Spanish NBS EQA scheme between May 2015 and September 2018. Measurands included: thyroid-stimulating hormone (TSH), immunoreactive trypsinogen (IRT), phenylalanine (Phe), tyrosine (Tyr), free carnitine (C0), acetylcarnitine (C2), propionylcarnitine (C3), butyrylcarnitine (C4), isovalerylcarnitine (C5), glutarylcarnitine (C5DC), hexanoylcarnitine (C6), octanoylcarnitine (C8), decanoylcarnitine (C10), myristoylcarnitine (C14), palmitoylcarnitine (C16), stearoylcarnitine (C18). TE APS were calculated as the 90th percentile of the measurement errors, considering 75% of the best results from each laboratory only. It was also studied whether the analytical performance was concentration-dependent. RESULTS: When TE APS were calculated including all methods, TSH, IRT, C16 and C18 showed the best analytical performance and Phe, C5DC and C10 showed the worst. Generally, TE APS decreased when considering only majority methods and higher TE APS were obtained for lower concentrations. DISCUSSION: Due to the lack of APS based on superior models, the proposed TE APS based on the SOTA can help NBS laboratories to set quality specifications.