Comprehensive Profiling of Carotenoids and Fat-Soluble Vitamins in Milk from Different Animal Species by LC-DAD-MS/MS Hyphenation

This paper describes a novel and efficient analytical method to define the profile of fat-soluble micronutrients in milk from different animal species. Overnight cold saponification was optimized as a simultaneous extraction procedure. Analytes were separated by nonaqueous reversed-phase (NARP) chromatography: carotenoids on a C₃₀ column and fat-soluble vitamins on a tandem C₁₈ column system. Besides 12 target analytes for which standards are available (<i>all-trans</i>-lutein, <i>all-trans</i>-zeaxanthin, <i>all-trans</i>-β-cryptoxanthin, <i>all-trans</i>-β-carotene, <i>all-trans</i>-retinol, α-tocopherol, γ-tocopherol, δ-tocopherol, ergocalciferol, cholecalciferol, phylloquinone, and menaquinone-4), the DAD-MS combined detection allowed the provisional identification of other carotenoids on the basis of the expected retention times, the absorbance spectra, and the mass spectrometric data. Retinol and α-tocopherol were the most abundant fat-soluble micronutrients and the only ones found in donkey's milk along with γ-tocopherol. Ewe's milk also proved to be a good source of vitamin K vitamers. Bovine milk showed a large variety of carotenoids that were absent in milk samples from other species with the only exception of <i>all-trans</i>-lutein and <i>all-trans</i>-zeaxanthin

Oxidized Buckypaper for Stir-Disc Solid Phase Extraction: Evaluation of Several Classes of Environmental Pollutants Recovered from Surface Water Samples

This paper describes, for the first time, the use of oxidized buckypaper (BP) as a sorbent membrane of a stir-disc solid phase extraction module. The original device, consisting of a BP disc (<i>d</i> = 34 mm) enveloped in a polypropylene mesh pouch, was designed to extract organic micropollutants (OMPs) from environmental water samples in dynamic mode. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was used to analyze the extracts. Several classes of pesticides and pharmaceuticals were chosen as model compounds to evaluate key parameters affecting the recovery rates. To this end, the effects of adsorption time, desorption time, stirring speed, type and volume of solvent, and sample volume were thoroughly examined. After optimization, a novel and in-depth study was conducted to find a correlation between physicochemical properties of the analytes and extraction yields. Recoveries were mainly governed by a combination of log<i>P</i> and p<i>K</i>_a values. As indicated, hydrophilic compounds with log<i>P</i> < 1 showed poor affinity for the oxidized BP, compounds having log<i>P</i> > 1 exhibited recoveries ranging between 50% and 100% depending on their p<i>K</i>_a, while compounds with p<i>K</i>_a between 6 and 7.5 gave low yields irrespective of their log<i>P</i>. The analytical method was also validated and tested as large scale screening method of OMPs in surface waters. The analysis of real samples revealed the presence of some nonsteroidal anti-inflammatory drugs, sulfonamides, and pesticides at low ng L^–1 concentration levels with relative standard deviations lower than 8%

Extraction of Emerging Contaminants from Environmental Waters and Urine by Dispersive Liquid–Liquid Microextraction with Solidification of the Floating Organic Droplet Using Fenchol:Acetic Acid Deep Eutectic Mixtures

In this work, several eutectic mixtures formed by fenchol and acetic acid at seven molar ratios (between 4:1 and 1:4) were characterized and studied for the first time for their possible application as extraction solvents in dispersive liquid–liquid microextraction based on the solidification of the floating organic droplet (DLLME-SFO). A group of 13 emerging contaminants (gemfibrozil, bisphenol F, bisphenol A, 17β-estradiol, testosterone, estrone, levonorgestrel, 4-tert-octylphenol, butyl benzyl phthalate, dibutyl phthalate, 4-octylphenol, 4-nonylphenol, and dihexyl phthalate) was selected and determined by liquid chromatography with ultraviolet and tandem mass spectrometry detection. Among the studied mixtures, only those of 2:1 and 1:1 provided the suitable features from an operational and repeatability point of view, suggesting that several eutectic mixtures of the same components may also provide similar results. Once the extraction conditions of both mixtures were optimized, the method was applied to the extraction of sea water, urine, and wastewater at different concentration levels, allowing the achievement of absolute recovery values between 49 and 100% for most analytes with relative standard deviation values below 19%. In addition, several samples of each type were analyzed, finding bisphenol A and gemfibrozil in some of them. The greenness of the method was also evaluated using the AGREEprep metric. The DLLME-SFO procedure was found to be very simple, quick, and effective and with a good sample throughput