Mineral oil certified reference materials for the determination of polychlorinated biphenyls from the National Metrology Institute of Japan (NMIJ)

Four mineral oil certified reference materials (CRMs), NMIJ CRM 7902-a, CRM 7903-a, CRM 7904-a, and CRM 7905-a, have been issued by the National Metrology Institute of Japan, which is part of the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST), for the determination of polychlorinated biphenyls (PCBs). The raw materials for the CRMs were an insulation oil (CRM 7902-a and CRM 7903-a) and a fuel oil (CRM7904-a and CRM 7905-a). A solution of PCB3, PCB8, and technical PCB products, comprising four types of Kaneclor, was added to the oil matrices. The total PCB concentrations in the PCB-fortified oils (CRM 7902-a and CRM 7904-a) are approximately 6 mg kg−1. In addition, the mineral oils which were not fortified with PCBs were also distributed as CRMs (CRM 7903-a and CRM 7905-a). Characterization of these CRMs was conducted by the NMIJ/AIST, where the mineral oils and the PCB solution were analyzed using multiple analytical methods such as dimethylsulfoxide extraction, normal-phase liquid chromatography, gel permeation chromatography, reversed-phase liquid chromatography, and chromatography using sulfoxide-bonded silica; and/or various capillary columns for gas chromatography, and two ionization modes for mass spectrometry. The target compounds in the mineral oils and those in the PCB solution were determined by one of the primary methods of measurement, isotope dilution–mass spectrometry (ID-MS). Certified values have been provided for 11 PCB congeners (PCB3, 8, 28, 52, 101, 118, 138, 153, 180, 194, and 206) in the CRMs. These CRMs have information values for PCB homologue concentrations determined by using a Japanese official method for determination of PCBs in wastes and densities determined with an oscillational density meter. Because oil samples having arbitrary PCB concentrations between respective property values of the PCB-fortified and nonfortified CRMs can be prepared by gravimetric mixing of the CRM pairs, these CRMs can be used for validation of PCB analyses using various instruments which have different sensitivities

Certification of butyltins and phenyltins in marine sediment certified reference material by species-specific isotope-dilution mass spectrometric analysis using synthesized (118)Sn-enriched organotin compounds

A new marine sediment certified reference material, NMIJ CRM 7306-a, for butyltin and phenyltin analysis has been prepared and certified by the National Metrological Institute of Japan at the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST). Candidate sediment material was collected at a bay near industrial activity in Japan. After air-drying, sieving, and mixing the material was sterilized with γ-ray irradiation. The material was re-mixed and packaged into 250 glass bottles (15 g each) and these were stored in a freezer at −30 °C. Certification was performed by use of three different types of species-specific isotope-dilution mass spectrometry (SSID–MS)—SSID–GC–ICP–MS, SSID–GC–MS, and SSID–LC–ICP–MS, with (118)Sn-enriched organotin compounds synthesized from (118)Sn-enriched metal used as a spike. The (118)Sn-enriched mono-butyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) were synthesized as a mixture whereas the (118)Sn-enriched di-phenyltin (DPhT) and triphenyltin (TPhT) were synthesized individually. Four different extraction methods, mechanical shaking, ultrasonic, microwave-assisted, and pressurized liquid extraction, were adopted to avoid possible analytical bias caused by non-quantitative extraction and degradation or inter-conversion of analytes in sample preparations. Tropolone was used as chelating agent in all the extraction methods. Certified values are given for TBT 44±3 μg kg(−1) as Sn, DBT 51 ± 2 μg kg(−1) as Sn, MBT 67 ± 3 μg kg(−1) as Sn, TPhT 6.9 ± 1.2 μg kg(−1) as Sn, and DPhT 3.4 ± 1.2 μg kg(−1) as Sn. These levels are lower than in other sediment CRMs currently available for analysis of organotin compounds

Long-term stability of relationships between reference materials for thromboplastins

Reference materials for thromboplastins are available from the World Health Organization (WHO) and the European Commission (EC). The long-term stability of the reference materials is an essential requirement and must be monitored. The relationship between two reference materials for rabbit thromboplastin, i.e. ERM-AD 149 (EC) and RBT/90 (WHO), has been monitored in the period 1996-2002. No significant trend with time was detected. In addition, the relationship between ERM-AD 149 and the reference material for bovine thromboplastin (i.e. OBT/79) has been determined in 1994 and in 2005 in multi-centre studies (n = 11 and n = 9, respectively). No significant changes were observed in the relationship between these reference materials when all results were included (5% significance level)

Nanotechnology and Plant Extracts as a Future Control Strategy for Meat and Milk Products

Plant extracts, well known for their antibacterial and antioxidant activity, have potential to be widely used preservatives in the food industry as natural alternatives to numerous synthetic additives which have adverse impacts on health and the environment. Most plant compounds and extracts are generally recognized as safe (GRAS). The use of preservatives is of great importance for perishable foods such as meat and milk, which, along with their products, are commonly consumed food items globally. However, the bioavailability of plant compounds could be diminished by their interaction with food components, processing, and storage. Nanoencapsulation of plant extracts, especially essential oils, is an effective method for their application in food model systems. This technique increases the bioactivity of plant compounds by increasing their physical stability and reducing their size, without negative effects on organoleptic properties. Furthermore, a recent study showed that plant extracts act as good bioreductants for biosynthesis of nanoparticles. This so-called green synthesis method using plant extracts is a rapid, relatively inexpensive, safe, and efficient method for synthesis of nanoparticles including silver, gold, iron, lead, copper, cobalt, palladium, platinum, zinc, zinc oxide, titanium oxide, magnetite, and nickel. Some of these nanoparticles have antimicrobial potential which is why they are of great interest to the food industry. In this chapter, the nanoencapsulation of plant extracts and plant extract-mediated synthesis of nanoparticles and their potential application in order to improve the safety and quality and prolong the shelf life of meat and milk products are reviewed and discussed