Physico-chemical properties study of solid state inulin

The aim of this research is to understand the solid state physical properties of inulin in regards to the spray-drying treatments. In this context, inulin powders were produced by pilot spray-drying a commercial inulin dispersion under various feed (Tfeed) and inlet air (Tin) temperatures. More particularly, the amorphous and crystalline properties of the powders were studied by developing different fine characterization tools, such as modulated differential scanning calorimetry or powder X-ray diffraction. When the temperature of the inulin – water systems increased, the crystallinity of the powder decreased. To a smaller extent, this tendency is also observed with the increase of the inlet air temperature of the spray drier. For example, an amorphous powder is obtained with a Tfeed of 90°C whatever the Tin (comprised between 120 and 230°C); whereas for a Tfeed of 80°C, a Tin of 230°C is necessary to obtain the same result. Adsorption isotherms were established on four powders covering a large range of crystallinity (crystallinity index from 0 to 92). The Guggenheim – Anderson – de Boer model was fitted to the experimental data. As the water content of the powders increased, the glass transition of inulin decreased. When the Tg droped below the storage temperature (20°C for example), the powders crystallized and underwent clumping phenomenon. Under these conditions, a continuous hard mass was observed for the amorphous powders; while their semi-crystalline counterparts were agglomerated but friable. To understand these changes, a kinetic study of the physical properties evolution and stability of an amorphous powder as a function of its water content was realized. These results allowed to correlate the Tg – water content relationship to the evolution of the powder’s behaviour, such as stickiness or hardening during storage

Development and validation of methods using UHPLC ESI MS/MS for the quantification of estrogenic compounds at ultra trace levels in different types of water

Natural estrogens (estrone: E1, 17-β-estradiol: E2, estriol: E3) and synthetic estrogen (17-α-ethinylestradiol: EE2) belong to the group of endocrine disrupting compounds (EDCs) harmful for wildlife and human. The European Union published a watch-list of substances including these estrogenic compounds and specified maximum acceptable method detection limit of 0.035 ng/L for EE2 and 0.4 ng/L for E1 and E2. These extremely low LODs are difficult to reach even using up-to-date analytical methods. LC-ESI-MS/MS characterized by a high sensitivity and specificity was the selected method. In the literature, ESI(-) mode was more commonly used. However, the target analytes are characterized by a low ionization efficiency in ESI(-) mode. To deal with this issue, analytes were derivatized and were analyzed in the opposite mode ESI(+). Pyridine-3-sulfonyl chloride was selected as derivatization reagent as it allowed a fast derivatization reaction, significantly increased the response of estrogenic compounds and led to specific fragments in MS/MS. The specificity of the product ions was studied by evaluating signal-to-noise ratios, chromatographic interferences and ion ratios in ground and surface water. A method with one SPE extraction was validated on mineral drinking water. The application of the method was then extended to surface water

Impact of the crystallisation pathway of inulin on its mono-hydrate to hemi-hydrate thermal transition

In this paper, we present the thermal properties of two inulins obtained from different crystallisation pathways. One was obtained by fractional precipitation of a saturated inulin solution and the second was from the crystallisation of a solid amorphous mulin. The thermal analyses were conducted by temperature resolved wide angle X-ray scattering (TRWAXS), differential scanning calorimetry (DSC) and thermogravimetry (TG). Although at room temperature both inulins presented similar X-ray diffractogram patterns characteristic of the mono-hydrate polymorph, they differed considerably by their thermal properties. During heating, a difference in the mono-hydrate to the hemi-hydrate polymorph transition occurred. Thermogravimetric analysis suggested a difference in the water mobility inside the material which had an impact on the thermal properties and hydrate transition of the crystalline inulin. (C) 2009 Elsevier Ltd. All rights reserved