A tool to assure the geographical origin of local food products (glasshouse tomatoes) using labeling with rare earth elements.

BACKGROUND: Trace element fingerprinting has been widely used for identification of provenance of regional food. In the case of products from conventional agriculture, it is expected that the elemental composition will comply with that of the commercially available substrate of the plants. Therefore, for products without a direct relationship with the regional soil the region-specific differences in elemental composition are no longer recognizable. The idea of this work is the labeling of tomatoes with rare earth elements (REE) in the ultra-trace range for food authentication. RESULTS: Labeling of tomatoes was carried out either by watering the soil with Nd- and Er-spiked water or by adding these elements as solid oxides to the soil. In both cases enrichment of Nd and Er relative to the control group was detected in tomato fruits and leaves using inductively coupled plasma-mass spectrometry. Tomato plants rapidly absorb the dissolved REE from the irrigation water, and watering for a short period just before ripeness is sufficient to induce REE labels. CONCLUSION: Labeling with trace amounts of REE could potentially be used to assure the provenance of tomatoes of local origin and separate these from products of foreign origin. © 2018 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Selective synthesis and derivatization of alkali metal silanides MSi(SiH3)3.

Greetings from silicon valley: Alkali metal silanides (H(3)Si)(3)Si(-)M(+) were shown to be selectively accessible for the first time by the reaction of neopentasilane Si(SiH(3))(4) with tBuOM or iPr(2)NLi. The method allows the convenient derivatization of higher silicon hydrides and provides a simple access for unprecedented systematic studies on the chemical behavior of hydropolysilanes (see scheme).

Partial halogenation of cyclic and branched perhydropentasilanes.

The perhydropentasilanes (H(3)Si)(4)Si and Si(5)H(10) were chlorinated with SnCl(4) to give chlorohydropentasilanes without destruction of the Si-Si backbone. Tetrachloroneopentasilane (ClH(2)Si)(4)Si (2) was prepared in high yield from (H(3)Si)(4)Si and 3.5 equiv of SnCl(4), while Si(5)H(10) and an equimolar amount of SnCl(4) afforded a mixture of ∼60% of ClSi(5)H(9) (1) with polychlorinated cyclopentasilanes and unreacted starting material, which could not be separated by distillation. The selective monochlorination of Si(5)H(10) was achieved starting from MesSi(5)Cl(9) (3; Mes = 2,4,6-trimethylphenyl) or TBDMP-Si(5)Cl(9) (4; TBDMP = 4-tert-butyl-2,6-dimethylphenyl). 3 or 4 was successfully hydrogenated with LiAlH(4) to give MesSi(5)H(9) (6) or TBDMP-Si(5)H(9) (7), which finally gave 1 along with aryl-H and Si(5)H(10) after treatment with an excess of liquid anhydrous HCl. All compounds were characterized by standard spectroscopic techniques. For Si-H derivatives, the coupled (29)Si NMR spectra were analyzed in detail to obtain an unequivocal structural assignment. The molecular structures of 2-4 were further confirmed by X-ray crystallography.

Authentication of meat and dairy products using rare earth element labeling and detection by solution based and laser ablation ICP-MS.

In order to meet the increasing customer demand for local food products, various methods for verification of food origin by means of region specific trace element fingerprinting have been developed. However, for products from conventional agriculture, without a close relationship to the local soil, other methods for food authentication are required. In an alternative approach, foodstuffs produced in a certain region, by a specific producer or under certain conditions can be safeguarded against imitation by chemical labeling. The objective of the present study was to develop a method for labeling lamb meat and goat milk by selective enrichment of terbium and thulium in the feed for the animals. Therefore, a distinctive rare earth element (REE) pattern is artificially introduced which can be determined in labeled food products. Detection of REE labels was carried out using inductively coupled plasma mass spectrometry (ICP-MS) after acid digestion. Alternatively, laser ablation ICP-MS (LA-ICP-MS) was applied, allowing direct analysis of bone samples and analysis of meat and milk samples after dry ashing and pressing pellets. After three weeks of administering 1000-fold terbium and thulium enriched feed to lambs, terbium and thulium enrichment was detected in all sample types except blood, following the trend bones > kidney > liver > heart > meat > kidney fat. Similarly, goat milk was successfully labeled after three weeks of feeding 500-fold terbium and thulium enriched feed. Hence, the present method allows discrimination of labeled from unlabeled animal products, while REE contents in all labeled products remained low enough to avoid any health risk for the consumer.

Rare Earth Element Labeling as a Tool for Assuring the Origin of Eggs and Poultry Products.

Laying hens were fed terbium and thulium supplemented feed in order to introduce a distinctive rare earth element pattern that allows discrimination of labeled from unlabeled poultry products. Samples of egg yolk, egg shells, meat, bones, liver, blood, and feces were analyzed using either conventional or laser ablation inductively coupled plasma mass spectrometry. Already after a short time of administering supplemented feed, terbium and thulium enrichment could be unambiguously detected in the products, while absolute terbium and thulium contents remained low enough to ensure safety for the customer. This method could potentially be applied to specifically label foodstuffs produced in certain regions or under certain conditions, in order to ensure food authenticity.