Determination of olaquindox, carbadox and cyadox in animal feeds by ultra-performance liquid chromatography tandem mass spectrometry

<p>Olaquindox, carbadox, and cyadox are chemically synthesised antibacterial and growth-promoting agents for animals. At high doses they may exert mutagenicity and hepatic and adrenal toxicities in animals. Regrettably, these substances are frequently abused or misused when added into animal feeds. Thus, developing a sensitive and reliable method for simultaneous determination of olaquindox, carbadox, and cyadox in different kinds of animal feeds is crucially important for food safety monitoring. In this paper we optimised instrumental conditions, extraction solvents, solid phase extraction cartridges, and pH of the loading solvents on the Oasis HLB cartridge. Under the optimal conditions, mean recoveries ranged from 74.1 to 111%, and intra-day and inter-day variations were lower than 14.6% and 10.8%, respectively. The limits of quantification for olaquindox, carbadox, and cyadox were 0.05 mg kg⁻¹, 0.10 mg kg⁻¹, and 0.025 mg kg⁻¹, respectively. The proposed method uses ultra-performance liquid chromatography tandem mass spectrometry and is sensitive and reliable for the simultaneous determination of olaquindox, carbadox, and cyadox in three kinds of animal feeds (specifically, mixed feed, concentrated feed, and additive premixed feed). This method has good precision, high sensitivity, and good reproducibility, and thus it can be used for convenient and accurate determination of olaquindox, carbadox, and cyadox in different kinds of animal feeds.</p

Studies of the Ligand Effect on the Synthesis of Dialuminoxanes by Various β-Diketiminato Ligands

Reactions of LH (L = HC­[C­(Me)­N­(2,6-Me₂C₆H₃)]₂) with Me_<i>n</i>AlCl_3–<i>n</i> in diethyl ether afforded the adducts LH·AlMe_<i>n</i>(Cl)_3–<i>n</i> (<i>n</i> = 2, <b>3</b>; 1, <b>4</b>; 0, <b>5</b>) in good yields. Treatment of <b>3</b> at elevated temperatures in toluene resulted in LAlMeCl (<b>2</b>) by intramolecular elimination of methane. The controlled hydrolysis of LAlMeCl (<b>2</b>) with equimolar amounts of water in the presence of N-heterocyclic carbene (NHC) gave a mixture of [LAl­(Me)]₂(μ-O) (<b>7</b>) and dimeric [LAlMe­(μ-OH)]₂ (<b>8</b>). A convenient route for the preparation of [LAlMe­(μ-OH)]₂ (<b>8</b>) was the NHC-assisted controlled hydrolysis of LAlMeI (<b>9</b>). Stepwise hydrolysis of LAlH₂ (<b>11</b>) gave dialuminoxane hydride [LAl­(H)]₂(μ-O) (<b>12</b>) and dialuminoxane hydroxide [LAl­(OH)]₂(μ-O) (<b>13</b>), respectively. Anhydrous treatment of LAlCl₂ (<b>1</b>) or LAlMeCl (<b>2</b>) with Ag₂O afforded chlorinated dialuminoxane [LAl­(Cl)]₂(μ-O) (<b>14</b>) and [LAl­(Me)]₂(μ-O) (<b>7</b>), respectively

Studies of the Ligand Effect on the Synthesis of Dialuminoxanes by Various β-Diketiminato Ligands

Reactions of LH (L = HC­[C­(Me)­N­(2,6-Me₂C₆H₃)]₂) with Me_<i>n</i>AlCl_3–<i>n</i> in diethyl ether afforded the adducts LH·AlMe_<i>n</i>(Cl)_3–<i>n</i> (<i>n</i> = 2, <b>3</b>; 1, <b>4</b>; 0, <b>5</b>) in good yields. Treatment of <b>3</b> at elevated temperatures in toluene resulted in LAlMeCl (<b>2</b>) by intramolecular elimination of methane. The controlled hydrolysis of LAlMeCl (<b>2</b>) with equimolar amounts of water in the presence of N-heterocyclic carbene (NHC) gave a mixture of [LAl­(Me)]₂(μ-O) (<b>7</b>) and dimeric [LAlMe­(μ-OH)]₂ (<b>8</b>). A convenient route for the preparation of [LAlMe­(μ-OH)]₂ (<b>8</b>) was the NHC-assisted controlled hydrolysis of LAlMeI (<b>9</b>). Stepwise hydrolysis of LAlH₂ (<b>11</b>) gave dialuminoxane hydride [LAl­(H)]₂(μ-O) (<b>12</b>) and dialuminoxane hydroxide [LAl­(OH)]₂(μ-O) (<b>13</b>), respectively. Anhydrous treatment of LAlCl₂ (<b>1</b>) or LAlMeCl (<b>2</b>) with Ag₂O afforded chlorinated dialuminoxane [LAl­(Cl)]₂(μ-O) (<b>14</b>) and [LAl­(Me)]₂(μ-O) (<b>7</b>), respectively