Malonic

The 14 OA standards (pyruvic, lactic, glycolic, 2-hydroxybutyric, 3-hydroxybutyric, malonic, succinic, fumaric, α-ketoglutaric, malic, 2-hydroxyglutaric, cis-aconitic, citric, and isocitric acid), and O-methoxyamine hydrochloride were purchased from Sigma-Aldrich (St. Louis, MO, USA). N-Methyl-N-(tert-butyldimethylsilyl) trifluoroacetamide (MTBSTFA) + 1% tert-butyldimetheylchlorosilane (TBDMCS) was obtained from Thermo Scientific (Bellefonte, PA, USA). Toluene, diethyl ether, ethyl acetate, and sodium chloride of pesticide grade were supplied by Kanto Chemical (Tokyo, Japan). All other chemicals were of analytical grade and used as received.

The 14 OA standards (pyruvic, lactic, glycolic, 2-hydroxybutyric, 3-hydroxybutyric, malonic, succinic, fumaric, α-ketoglutaric, malic, 2-hydroxyglutaric, cis-aconitic, citric, and isocitric acid), and O-methoxyamine hydrochloride were purchased from Sigma-Aldrich (St. Louis, MO, USA). N-Methyl-N-(tert-butyldimethylsilyl) trifluoroacetamide (MTBSTFA) + 1% tert-butyldimetheylchlorosilane (TBDMCS) was obtained from Thermo Scientific (Bellefonte, PA, USA). Toluene, diethyl ether, ethyl acetate, and sodium chloride of pesticide grade were supplied by Kanto Chemical (Tokyo, Japan). All other chemicals were of analytical grade and used as received.

Isotactic PP (Ecolen HZ42Q) with melt flow index equal to 18 g/10 min, tensile strength equal to 33 MPa, and melting point of 168–171 °C was obtained from Hellenic Petroleum S.A., Thessaloniki, Greece. A masterbatch (Bondyram^® 1001) with PP grafted with maleic anhydride (PP-g-MA), with MA content of 1%, melt flow index equal to 100 g/10 min, and melting point of 160 °C, obtained from Polyram Plastic Industries Ltd., Gilboa, Israel, was used as a compatibilizer. Wollastonite in the form of needle-like particles (NYAD M9000) with aspect ratio equal to 3 (9 μm length to 3 μm diameter) was kindly supplied by Imerys Minerals Ltd., Paris, France.
Two different organic solvents were used, namely, Ethanol and carbon tetrachloride, for the modification procedure of wollastonite. Ethanol was purchased from Honeywell, Charlotte, NC, USA (purity ≥ 99.8%), while carbon tetrachloride was purchased from Fluka Chemie AG, Buchs, Switzerland (purity > 99.5%).
Myristic, malonic, glutaric, pimelic, and suberic acid were purchased from Sigma-Aldrich, St. Louis, MO, USA, while maleic acid was purchased from Alfa Aesar, Haverhill, MA, USA. Potassium bromide (KBr, >99.5%) was purchased from Chem-Lab, Zedelgem, Belgium and was dried at 170 °C for 3 h prior to use. All other chemicals were used as received (unless otherwise noted).