Merck

Simultaneous LC/MS Analysis of Carotenoids and Fat-Soluble Vitamins in Costa Rican Avocados (Persea americana Mill.).

Molecules (Basel, Switzerland) (2019-12-15)
Carolina Cortés-Herrera, Andrea Chacón, Graciela Artavia, Fabio Granados-Chinchilla
RESUMEN

Avocado (a fruit that represents a billion-dollar industry) has become a relevant crop in global trade. The benefits of eating avocados have also been thoroughly described as they contain important nutrients needed to ensure biological functions. For example, avocados contain considerable amounts of vitamins and other phytonutrients, such as carotenoids (e.g., β-carotene), which are fat-soluble. Hence, there is a need to assess accurately these types of compounds. Herein we describe a method that chromatographically separates commercial standard solutions containing both fat-soluble vitamins (vitamin A acetate and palmitate, Vitamin D2 and D3, vitamin K1, α-, δ-, and γ-vitamin E isomers) and carotenoids (β-cryptoxanthin, zeaxanthin, lutein, β-carotene, and lycopene) effectively (i.e., analytical recoveries ranging from 80.43% to 117.02%, for vitamins, and from 43.80% to 108.63%). We optimized saponification conditions and settled at 80 °C using 1 mmol KOH L-1 ethanol during 1 h. We used a non-aqueous gradient that included methanol and methyl tert-butyl ether (starting at an 80:20 ratio) and a C30 chromatographic column to achieve analyte separation (in less than 40 min) and applied this method to avocado, a fruit that characteristically contains both types of compounds. We obtained a method with good linearity at the mid to low range of the mg L-1 (determination coefficients 0.9006-0.9964). To determine both types of compounds in avocado, we developed and validated for the simultaneous analysis of carotenoids and fat-soluble vitamins based on liquid chromatography and single quadrupole mass detection (LC/MS). From actual avocado samples, we found relevant concentrations for cholecalciferol (ranging from 103.5 to 119.5), δ-tocopherol (ranging from 6.16 to 42.48), and lutein (ranging from 6.41 to 15.13 mg/100 g dry weight basis). Simmonds cultivar demonstrated the higher values for all analytes (ranging from 0.03 (zeaxanthin) to 119.5 (cholecalciferol) mg/100 g dry weight basis).

MATERIALES
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Sigma-Aldrich
(+)-γ-Tocopherol, ≥96% (HPLC)
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all-trans-Astaxanthin, analytical standard
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Lycopene, analytical standard
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Sodium sulfate, anhydrous, granular, free-flowing, Redi-Dri, ACS reagent, ≥99%
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Chloroform, ACS spectrophotometric grade, ≥99.8%, contains 0.5-1.0% ethanol as stabilizer
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Tocopherols, mixed, FCC, Low-α type, FG
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Cholecalciferol, analytical standard
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β-Carotene, synthetic, ≥95% (HPLC), crystalline
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(±)-α-Tocopherol, analytical standard
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Pyrogallol, ACS reagent, ≥99%
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Retinol palmitate, analytical standard
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δ-Tocopherol, analytical standard
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Retinyl acetate, analytical standard
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Vitamin K1, BioXtra, ≥99.0% (sum of isomers, HPLC), mixtur of isomers
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β-Cryptoxanthin, ≥97% (TLC)
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Zeaxanthin, analytical standard
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2-Propanol, HPLC Plus, for HPLC, GC, and residue analysis, 99.9%