Honey is a natural sweetener and as such it can be greatly affected by fraudulent practices like mislabeling (blossom honey sold as honeydew honey) or the addition of illegal substances (syrup or water). Phenolic compounds, flavonoids and phenolic acids, are the most abundant antioxidant nutritive constituents and proved to be beneficial to human health. The concentration and the presence of these compounds are strictly connected to the geographical and/or the botanical origin of the honey. To this end, a method has been optimized and validated for the simultaneous determination of 25 phenolic compounds.
At first, three different extractants were tested in order to find the solvent which yields the highest recoveries for the phenolic compounds and it was revealed that ethyl acetate was the most suitable. Afterwards, the separation of the analytes was performed in an ultra-high pressure liquid chromatography system combined with a high resolution quadrupole time of flight mass spectrometry detector (UPLC-qTOF MS). The developed method was tested in oak honeydew samples and it was validated based on the Eurachem guidelines. R^2 was over 0.99 in the most analytes. Mean recoveries ranged from 75 to 105% in each spiked level. RSD % values was from 0.90 % to 14.1% concerning repeatability and from 1.64 % to 22.0% according to intermediate precision. LODs ranged from 0.10 to 0.76 mg L^-1. Finally, the developed method quantified 9 and semi-quantified 3 phenolic compounds in oak samples, importing new data on the limited information about the phenolic content of oak honey.

Water is a basic human need and is provided to the crew of International Space Station (ISS) from the water storage/transfer systems that are placed in there. Except of the direct regular supply of drinking water, the development of proper water recycling systems is equally critical as the employment of reliable automatic water quality monitoring systems. A fully automated on-line analyzer for ammonium determination in consumed drinking water and/or recycled hygiene water produced on board the ISS is needed according to ESA requirements. In this work, a trade-off methodology similar to a weighted-point method, was developed to evaluate appropriate analytical systems, adaptable to space flight requirements. The developed scoring methodology for the assessment of the suitability of the techniques, was based on scales and weighting factors for various applied criteria, like analytical performance (e.g. LOD, LOQ, accuracy, repeatability), adaptation to space flight conditions (e.g. microgravity applicability, volume/mass of the analyzer, solutions consumption, wastes production etc.), safety criteria (e.g. use of hazardous materials/reagents, pressure, heating, flammability), etc. as provided by the manufacturers or in literature. The evaluation approach offers a somehow arbitrary in metrics but still reasonable and countable discrimination between analytical techniques. This evaluation method is a first-time metrological contribution to the frequently appearing issue to select between available techniques taking into account diverse requirements. The proposed approach may be applicable also to evaluation needs for specific analytical techniques/methods, in order to be employed for various other customized purposes. In this particular case, among several technologies which were investigated, sequential injection systems meets the specifications for on-line monitoring in space conditions as it is an integrated flow manifold with small dimensions operating in a totally closed loop preventing any contact or release of the fluids/gases inside the space environment. Also, an appropriate ammonium ion selective electrode with real-time potassium compensation may be used as an alternative solution.

Ochratoxin A is structurally related compounds produced as secondary metabolites mainly by toxigenic strains of Aspergillus and Penicillium species in/on food and feeds. Among the mycotoxins, ochratoxin A has several toxicological effects such as nephrotoxic, hepatotoxic, neurotoxic, teratogenic and immunotoxic. As a result of their potential threat for health, regulations on mycotoxins have been established in many countries in order to protect consumers from their harmful effects. Based on the regulatory limits, accurate and reliable determination of mycotoxins in foods becomes very important for food safety and international trade. The traceability of ochratoxin A measurement results can be achieved through the use of a matrix reference material (RM) and proficiency tests (PT). The proposed material is a candidate RM for the determination of ochratoxin A level in wheat. Production of RM includes steps of planning, feasibility, processing, homogeneity and stability tests, and characterization. Processing of raw material, selection of the units for the homogeneity and stability tests and within-lab characterization for real scale production have been carried out, and material was ready to be distributed to laboratories as PT in order to control the accuracy of their results. Raw material was blended by a blade mixer, ground, sieved and vacuum packed in aluminium packages. The validated standard method was used for determination of ochratoxin A. Relative standard deviations achieved were less than 8%.

The Institute of Public Health is the first public health institution in the FYROM that has established Quality Management System according to ISO/IEC 17025. The accreditation has been granted by the National Institute for Accreditation in December 2006. Since then, the maintenance and improvement of the Quality Management System remains a key element in our policy.
It is well-known that one of the elements by which laboratories can demonstrate their competence is through participation in Proficiency Testing (PT) activities. Therefore, our laboratory adopted practice to participate in at least one PT scheme relating to each sub-discipline per a year. Since the first accreditation, our laboratory participated in 15 PT schemes, organized by different providers, such as: Muva Kempten Quality Management & Laboratory Services; FAPAS; DRRR Deutsches Referenzbüro für Lebensmittel- Ringversuche und Referenzmaterialien; LGC; Asia Pacific laboratory Accreditation Cooperation etc.
The most frequently analyzed matrices were: cream, powdered milk, yoghurt butter, cheese, oily dressing, soft drinks, cabbage puree; while the most analyzed parametres were: fat and water content, dry matter, protein content, pH, benzoic acid, nitrates, caffeine, saccharine, potassium acesulfame, citric acid, fructose, glucose, sucrose, total sugars.
Total of 60 parameters were tested, and 49 from the obtained results (81.7%) were evaluated as satisfactory, 2 results (3.3%) were assessed as questionable, while 9 (15.0%) were evaluated as unsatisfactory. The investigation shown that unsatisfactory performance is most frequently due to the systematic errors, such as: improper matrix homogenization, incomplete extraction or inadequate drying and cooling of glassware to constant temperature.

Small changes in the ¹⁸O/¹⁸O ratio can provide a fingerprint that provides a unique identifier for the origin of particular compounds within a food, which has been proved be a valuable tool for fighting against fraud food. As the backbone of triglyceride in fat, glycerol contains three non-exchangeable oxygen, which could be used to reveal the biosynthetic origin of corresponding fat. However, the need for highly pure glycerol using tedious procedures for off-line IRMS methods or GC-IRMS analysis limited the researches and applications of glycerol ¹⁸O/¹⁶O ratio in edible oil authenticity control. In this paper, a new method, with time and cost-saving procedures, is introduced for reliable, rapid, and accurate determination of the ¹⁸O/¹⁶O ratio of glycerol orginated from triglyceride in fat: By saponification in 20 volumes of KOH methanol solution, the glycerides from different origin were converted to free glycerol and to fatty acid methyl esters (FAMES); 2,2,4-Trimethylpentane were added and the upper layer were removed after shook several times; molecular sieve was added to trap the microscale water; the ¹⁸O/¹⁶O ratio was measured using GC-Py-IRMS systems. Using standard correction procedures, the method above for δ¹⁸O determination was assessed, good precision that better than 0.4‰ was obtained, the reproducibility of δ¹⁸O values from triglyceride was better than ±0.7‰. The validation of the method was carried out by measuring the intimate triglyceride samples that mixed with glycerol with known δ¹⁸O value, and a very good agreement between the measured values and the predicted data. In addition, 3 animal fats and 10 edible oil were analyzed, the mean δ¹⁸O value of glycerol samples from animal fat was approximately 16.2‰ which close to the peanut oil, δ¹⁸O value of the edible oils that from crop plant were higher than animal fat but lower than that from woody plant.