Coatings in food contact materials: Potential source of genotoxic contaminants?

Up till now, no harmonized EU regulation exists on chemicals used in coatings for food contact materials (FCM). Therefore, these substances need to comply with the general provisions of EU Regulation 1935/2004 and, if present, with national legislation. Different 'inventory lists' of compounds that might be present in coatings are available, but for hundreds of these substances, the potential human health impact of their use in FCM coatings has not (recently) been evaluated. Since detailed evaluation of all compounds is not feasible, a pragmatic approach was developed to identify substances with a potential concern for human health. First, an inventory was assembled containing all substances potentially used in coatings. Afterwards, the genotoxic potential of the non-evaluated substances was predicted in silico using two structure-activity relationship (SAR) software programs. For substances yielding structural alerts in both models, genotoxicity data were collected from previous European evaluations in a non-FCM context and from the European CHemicals Agency (ECHA) website. In total, 53 substances were identified as genotoxic in both in silico models, of which ten were considered to be of high concern. For most of the substances, additional toxicological information is needed.

Development and validation of an ultra-high performance liquid chromatography-tandem mass spectrometry method to measure creatinine in human urine.

Despite decades of creatinine measurement in biological fluids using a large variety of analytical methods, an accurate determination of this compound remains challenging. Especially with the novel trend to assess biomarkers on large sample sets preserved in biobanks, a simple and fast method that could cope with both a high sample throughput and a low volume of sample is still of interest. In answer to these challenges, a fast and accurate ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed to measure creatinine in small volumes of human urine. In this method, urine samples are simply diluted with a basic mobile phase and injected directly under positive electrospray ionization (ESI) conditions, without further purification steps. The combination of an important diluting factor (10(4) times) due to the use of a very sensitive triple quadrupole mass spectrometer (XEVO TQ) and the addition of creatinine-d3 as internal standard completely eliminates matrix effects coming from the urine. The method was validated in-house in 2012 according to the EMA guideline on bioanalytical method validation using Certified Reference samples from the German External Quality Assessment Scheme (G-Equas) proficiency test. All obtained results for accuracy and recovery are within the authorized tolerance ranges defined by G-Equas. The method is linear between 0 and 5 g/L, with LOD and LOQ of 5 × 10(-3) g/L and 10(-2) g/L, respectively. The repeatability (CV(r) = 1.03-2.07%) and intra-laboratory reproducibility (CV(RW) = 1.97-2.40%) satisfy the EMA 2012 guideline. The validated method was firstly applied to perform the German G-Equas proficiency test rounds 51 and 53, in 2013 and 2014, respectively. The obtained results were again all within the accepted tolerance ranges and very close to the reference values defined by the organizers of the proficiency test scheme, demonstrating an excellent accuracy of the developed method. The method was finally applied to measure the creatinine concentration in 210 urine samples, coming from 190 patients with a chronic kidney disease (CKD) and 20 healthy subjects. The obtained creatinine concentrations (ranging from 0.12 g/L up to 3.84 g/L) were compared, by means of a Passing Bablok regression, with the creatinine contents obtained for the same samples measured using a traditional compensated Jaffé method. The UHPLC-MS/MS method described in this paper can be used to normalize the concentration of biomarkers in urine for the extent of dilution.

Calculation of the decision limit (CCalpha) and the detection capability (CCbeta) for banned substances: the imperfect marriage between the quantitative and the qualitative criteria.

Initially in the Decision 2002/657/EC the criteria for the calculation of the decision limit (CCalpha) and the detection capability (CCbeta) have been estimated as purely quantitative (alpha-error is 1% and beta-error is 5%). In 2004, the European Commission has issued a document to provide guidance for the interpretation of the 2002/657/EC. In this document it is mentioned that also qualitative criteria should be fulfilled. Therefore, the calculated CCalpha and CCbeta must be verified by using fortified samples. The method should be able to detect/identify the target component in 50% of the cases at CCalpha and in 95% of the cases at CCbeta. Analytical methods for the analysis of nitroimidazoles, nitrofurans and corticosteroids with LC-MS/MS have been validated by fortifying blank samples below and above the MRPL. CCalpha and CCbeta were calculated using the ISO 11843 approach. In addition, the frequency of methodical compliance for the qualitative criteria was determined at each concentration level. It was observed that at the calculated CCalpha and CCbeta levels the qualitative criteria were not fulfilled. It was concluded that the detection capability of the analytical method should be calculated by using decreasing fortification levels at and below the MRPL. A protocol validating methods for banned substances by limiting the number of samples is presented and the qualitative criteria for the assessment of CCalpha and CCbeta were verified based on the same set of data without the need of performing additional validation experiments.