Micronutrients with anionic character

The micronutrients with anion specificity (i.e. non-metals) which may be added to foods are, according to the Regulation EC 1170/2009 of the European Parliament and the Council : iodine, selenium, fluoride and boron.

The chemical formulations of micronutrients with anionic character as well as their NRV are given in table 2.

Table 2. Chemical formulations of the anionic mineral substances which may be added to foods

Micronutrient Measure

unit NRV Chemical formulations Fluoride mg 3.5 sodium fluoride ; potassium fluoride Iodine µg 150 sodium iodide ; sodium iodate ; potassium

iodide ; potassium iodate

Selenium µg 55 selenium enriched yeast ; sodium selenate ; sodium hydrogen selenite ; sodium selenite

Boron mg NE* boric acid ; sodium borate

*NE – not established

From the anionic minerals used in fortified foods selenium and iodine are more often found. Less often is used boron. In the case of anionic nutrients the tolerable upper intake levels, according to Scientific Committee on Food (SCF) and the European Food Safety Authority (EFSA) are: F – 7 mg, I – 600 µ g, Se – 300 µg, B – 10 mg/day.

The presence of too small and insignificant amounts of micronutrients in foods would not offer any benefit to consumers and would be misleading. Thus, in order to be allowed to be declared in nutrition labelling, vitamins and minerals added to foods should be at least a significant amount, i.e. 15% of the RDA per 100g or 100ml (Annex of Directive 90/496/EEC).

CONCLUSIVE DATA

1. In case of fortified foods an important aspect is related to the source compounds of minerals, namely the chemical formulations which can be used in their manufacture.

3. Mostly the following food categories are fortified : beverages excluding dairy products;

dairy products and analogues; cereals and cereal products; confectionary; fats and oils, and fat emulsions.

REFERENCES

1. Berdanier C.D. - Advanced Nutrition: Micronutrients. CRC Press, Boca Raton, 1998.

2. Brody T. – Nutritional biochemistry, Academic Press, San Diego, 1994.

3. Champe P.C., Harvey R.A. – Nutrition, pp. 297-309, in Illustrated Review Biochemistry (Champe P.C., Harvey R.A., Eds.), J.B. Lippincott Comp, Philadelphia, 1987.

4. Chaney S.G. – Principles of nutrition II. Micronutrients, pp.1115-1147, in „Textbook of Biochemistry” (Devlin T.M., Ed.), Wiley-Liss Inc., New York-Chichester-Brisbane-Toronto-Singapore, 1992.

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5. Gârban Z., Gârban Gabriela – Human nutrition (in Romanian), Vol.I , ed. 3, Ed.

Orizonturi Universitare, Timişoara, 2003.

6. O'Dell B.L., Sunde R.A. (Eds.) - Handbook of nutritionally essential mineral elements.

New York, Marcel Dekker Inc., 1997.

7. Richardson D.P. - Risk management of vitamins and minerals: a risk categorisation model for the setting of maximum levels in food supplements and fortified foods, Food Science and Technology Bulletin: Functional Foods, 2007, 4 (6), 51–66.

8. Shrimpton D. H. - Vitamins and minerals: a scientific evaluation of the range of safe intakes, Council for Responsible Nutrition, UK, 1997.

9. *** - Regulation (EC) No 1925/2006 of the European Parliament and of the Council of 20 December 2006 on the addition of vitamins and minerals and of certain other substances to foods

10. *** - Commission Regulation (EC) No. 1170/2009 of November 2009 amending Directive 2002/46/EC and Regulation (EC) No 1925/2006 as regards the lists of vitamins and minerals and their forms that can be added to foods, including food supplements.

Official Journal of the European Union, 1,12,2009

11. *** - Regulation (EU) No 1169/2011 of the European Parliament and of the Council of 25 October 2011 on the provision of food information to consumers, amending Regulations (EC) No 1924/2006 and (EC) No 1925/2006 of the European Parliament and of the Council, and repealing Commission Directive 87/250/EEC, Council Directive 90/496/EEC, Commission Directive 1999/10/EC, Directive 2000/13/EC of the European Parliament and of the Council, Commission Directives 2002/67/EC and 2008/5/EC and Commission Regulation (EC) No 608/2004

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Single Crystalline Micrometric Magnetite for Magnetic Resonance Imaging

Corina Beljung¹, Mihaela Luminita Kiss¹, Adrian Ieta², Marius Chirita^3,*

1Politehnica University, Timisoara; ²Department of Physics, SUNY Oswego, NY, USA;^.

3National Institute for Research and Development in Electrochemistry and Condensed Matter,Timisoara;

*email: chirifiz@gmail.com

A major drawback of using metal oxide nanoparticles as contrast agent in MRI is related to their low saturation magnetization mainly due to their particle size. The current works seeks to solve this problem by increasing the number of nanoparticles, of micrometer sized clustered particles. The studies shows that to be effective in improving MRI signal, millions of ultrasmall superparamagnetic iron oxide nanoparticles are needed to mark a single cell which is a dificulty. A better solution to this problem is to use singlecrystalline particles, in micrometer domain. Micrometric magnetite singlecrystals with average size of 10µm (along the <001> axis) with unusual superparamagnetic behavior at room temperature was synthesized by us through hydrotermal decomposition of Fe³⁺-Na4EDTA complex. Based on this lately original results regarding the obtaining of single crystalline micrometric domain (10-50µm) iron oxide (magnetite) with superparamagnetic behaviour generic named by as SCMSPIO, we believe that it could be involved in many interesting applications including their formulation as T2 contrast agents for successfully exploring by MRI.

Single crystals of Fe₃O₄ with micrometric dimensions of 10µm and superparamagnetic behaviour were synthesized. We tasted these particles as contrast agent in MRI experiments and at this stage of experiments the nuances of grey which we obtained show promising effects and they correspond to our objective (see figures 1 an 2 presented below).

Fig. 1, Three representative phantoms Fig.2, The grey nuances The results indicate that the choice of appropriate concentration might give a good contrast in MRI applications. Further in vivo experiments on animals are in progress. Taking into account the dimensions of the cells (10µm -100µm), this particle could be appropriate for other medical applications such as intracellular hyperthermia, controlled drug delivery system (site specific drug delivery), cellular Magnetic Resonance Imaging (MRI), monitoring cell migration for cell therapy, multimodal cancer therapy, immunomagnetic separation of cells, detection, immobilization and modification of biologically active compounds, cell labelling;

magnetic separation of cells, magnetic resonance contrast agents, gene delivery, multi-modal cancer therapy.

Keywords: MRI, superparamagnetic, magnetite, micrometric, biomedical.

141

Influence of CO₂ upon UV-Vis spectroscopy of silica-tetra-3,4-dimethoxy-phenyl-porphyrin hybrid nanomaterial

Ionela Creanga¹, Anca Palade¹, Anca Lascu¹, Ileana Cernica², Mihaela Birdeanu^1,3, Eugenia Fagadar-Cosma¹

1Institute of Chemistry Timisoara of Romanian Academy, 24 M. Viteazul Ave, 300223-Timisoara, Romania

2National R&D Institute for Microtechnology, 126 A Erou Iancu Nicolae Str., Voluntari, 077190 Bucharest, Romania

3National Institute for Research and Development in Electrochemistry and Condensed Matter, 1 PlautiusAndronescu Street, 300224 Timisoara, Romania

Abstract

A symmetrical substituted aryl porphyrin was incorporated by sol-gel method to generate a silica hybrid nanomaterial that preserves the UV-vis absorption properties of bare porphyrin.

The novel hybrid demonstrated to be a sensitive material for CO₂ detection. The sol-gel synthesis was monitored by UV-vis spectroscopy. Atomic force microscopy was performed for the hybrid before and after CO2 detection and important changes in the aggregation behavior of the nanomaterial were observed.

Keywords: porphyrin-silica hybrid, sol-gel, UV-vis, CO2 detection, AFM

Introduction

In 1997, for the first time a phosphorescence signal from a porphyrin encapsulated in a sol-gel matrix was used for gaseous oxygen sensing [1]. This result accelerated work into other optical sensors using water-insoluble luminescent dye/sol-gel matrices.

Sol-gel process affords easy immobilization of any porphyrin retaining the optical and sensing properties of the dye, due to the high homogeneity of the porphyrin molecules into the sol-gel matrices. The critical issues remain the tailoring of sol-gel materials to inhibit leaching of porphyrin, and to achieve enhanced sensor performance in terms of stability, response time, sensitivity, repeatability and selectivity.

Based on our previous studies regarding CO2 detection [2] in this paper the porphyrin was incorporated into a silica matrix by sol-gel method in two steps acid-base catalysis and used as optical sensor for the detection of CO₂ in wet environment.

OMe

MeO

Figure1. Structure of tetra (3,4-dimethoxy-phenyl)-porphyrin.

142 Experimental

2.1. Reagents

All reagents used in this work were p a grade provided by Merck, Fluka and Sigma-Aldrich.

2.2. Sol-gel synthesis was done by adapting previously reported paper [3]. A mixture of H2O (2,730g; 0,152mmol ) and HCl 37% (0,037g; 1,01 mmol) were added by dripping under continuous stirring to a solution of TEOS (7,9g; 0,038moli) dissolved into EtOH (6,98g;

0,152 mmol) containing a mixture of 8 mg porphyrin (0.88x10^-5 mmol) dissolved in 14 ml THF. The molar ratios were: TEOS:EtOH:H2O:HCl= 1:4:4:0,01. After 40 minutes, the second basic step was started by slowly adding of NH3 1.6g (solution of NH3 25%+9g H2O).

Transparent gel colored in violet was obtained instantly.

2.3. Apparatus

UV-visible spectra were registered on JASCO UV- V-650 visible spectrometer using 1 cm pass cells. Atomic force microscopy (AFM) investigations were performed on Nanosurf®EasyScan 2 Advanced Research AFM. AFM images were obtained in contact mode.

Results and discussion

The hybrid material was characterized after first step of acid catalysis and in the final step of base catalysis. As revealed by Figure 2, the properties of porphyrin are preserved in both steps of catalysis. Our interest was to incorporate into the hybrid a porphyrin that is neutral, not a protonated one, so that we choose for the tests to CO2 detection the hybrid preserving the properties of the initial porphyrin base that is the hybrid after gelation in the basic step.

Figure 2. The UV-vis of the bare porphyrin and of the hybrids, at the same concentration in THF

The selected hybrid was further subjected to test to CO2 and by increasing the quantity of gas introduced in the vial containing the gel (rate of 1µ L/min), the intensity of the Soret band of the nanomaterial increased also, as presented in Figure 3. The dependence between the intensity of the Soret band of the silica-porphyrin hybrid and the CO₂ concentration is linear.

A very good correlation coefficient is obtained.

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Figure 3. UV-vis spectra showing the linear dependence between CO₂ increasing of concentration and the increase of Soret band intensity for porphyrin-silica hybrid.

Due to the fact that the shape of the spectrum does not change during experiments we cannot presume that the mechanism of detection is based on the increase of acidity of the medium by CO2 introduction. So other hypothesis can be some adsorption phenomena of CO2 that might be accompanied by morphology and topography changes of the hybrid material. The aggregates of hybrid before CO₂ addition, investigated by AFM, look uniform, with small pores and with mean surface of islands of 0.0025 µm² as presented in Figure 4.

Figure 4. The surface image of hybrid nanomaterial before CO₂ addition.

The aggregates of hybrid after CO2 interference are significantly bigger, look like irregular straw –type assemblies having the height of 68 nm, the mean surface of 0.0181 µm² and the

144

mean volume of 0.00013 µm³. The diameter is varying in the range of 366 nm up to 791 nm (Figure 5).

Figure 5. The surface image of hybrid nanomaterial after CO₂ addition.

Conclusion

A symmetrical A4B substituted porphyrin was incorporated into a silica matrix by sol-gel method in two steps acid-base catalysis and used as optical sensor for the detection of CO2 in wet environment.

By increasing the quantity of CO₂ gas introduced in the vial containing the gel the intensity of the Soret band of the nanomaterial increased also, the dependence between being linear.

AFM studies show important changes regarding the surface morphology before and after CO2

addition to the hybrid nanomaterial, these indicating a probable absorption mechanism, not one based on acidity changes, as expected.

Acknowledgements

The authors from Institute of Chemistry Timisoara of Romanian Academy are kindly acknowledging the support from Program 3-Porphyrins/2015 and STAR Programme- SAFEAIR Project 76/2013.

References

[1] L. Sang-Kyung, O. Ichiro, Anal. Chim. Acta 342 (1997) 181-188.

[2] E. Fagadar-Cosma, D. Vlascici, G. Fagadar-Cosma, A. Palade, A. Lascu, I. Creanga, M.

Birdeanu, R. Cristescu, I. Cernica, Molecules 19(12) (2014) 21239-21252.

[3] E. Fagadar-Cosma, C. Enache, G. Fagadar-Cosma, C.Savii, J. Optoelectron. Adv. Mat. 9 (2007) 1878.

145

Detection of Phosphine Derivates Using Metalloporphyrins

Anca Palade¹, Ionela Creanga¹, Anca Lascu¹, Eugenia Fagadar-Cosma¹

Institute of Chemistry Timisoara of Romanian Academy, M.Viteazul Ave, No. 24, 300223-Timisoara, Romania

Abstract

Starting from the knowledge that phosphine derivatives exhibit medium/high toxicity, in this study we focused on the behavior of Co(II)- 5,10,15,20-tetratolyl-porphyrin (CoTTP) and Mn(III)-5,10,15,20-tetraphenyl-porphyrin chloride (MnTPPCl) as active UV-vis chromophores for the detection of triphenylphosphine oxide (LC50=12.2µ g/mL, LC90=29.5µ g/mL). The increase of triphenylphosphine oxide concentration generates the hypochromic effect on the Soret bands of the two metalloporphyrins. A comparison regarding the efficiency of the two metalloporphyrins in detecting phosphine derivatives was done.

Keywords: Co(II)-tetratolylporphyrin, Mn(III)-tetraphenylporphyrin, UV-vis, phosphine derivatives-detection, AFM.

Introduction

Due to dπ-pπ bonding that diminishes the electron density on oxygen, tertiary phosphine oxides are weak bases. Triphenylphosphine oxide (Ph3PO) is a widely used reagent material for synthesis of organophosphorus compounds and as catalyst, cocatalyst, Lewis base and monodentate neutral oxygen donor ligand. It is already known that Mn and Mg have a strong affinity to PO group in Ph3PO [1] and the coordination chemistry of P=O ligands and their coordination capabilities were largely studied [2].

Complexes of lanthanide nitrates with phosphine oxides have been investigated since the 1960s [3]. Due to its versatile ligand properties triphenylphosphine oxide was used in synthesis of TiO2-hybrids incorporating Eu³⁺ in order to improve Eu³⁺ luminescence [4] or in the polymeric composites for the detection of dopamine [5]. The detection of Ph3PO was reported by ³¹P-NMR in complexes to silanes, siloxanes and stannanes [6] but in this study, related to our previous research [7] we proposed a facile and non-toxic detection, using a Mn-porphyrin, namely: Mn(III)-5,10,15,20- tetraphenyl-21H,23H porphyrin chloride (structure in Figure 1).

Mn Cl N N

N N

N Co

N

N N

Figure 1. Structures of Mn(III)-5,10,15,20-tetraphenyl-porphyrin chloride (MnTPPCl), triphenylphosphine oxide and Co(II)- 5,10,15,20-tetratolyl-porphyrin (CoTTP).

2. Experimental

In document PROCEEDINGS OF THE (Pldal 139-146)