Analytical Problems in Separation of Selenomethionine and Its Oxidative Product in HILIC HPLC

Abstract

Selenomethionine (SeMet) is one of the main selenium forms in foods and supplements. Determining its presence in natural food samples creates difficulties due to possible oxidation processes. The objective of this study was to evaluate the possible degradation of SeMet in water extracts of green teas, one of the most consumed beverages worldwide. Such a medium has not been investigated at this time. The HILIC-HPLC MS/MS method with different stationary phases was used to achieve the satisfactory separation of SeMet and selenomethionine oxide (SeMetO). The addition of dithiothreitol and β-mercaptoethanol, recommended to ensure that SeMet is kept in the reduced form, was also evaluated. The best separation was achieved using the zwitterionic HILIC stationary phase coupled to mass spectrometry and MeOH with water (85/15, v/v) as the eluent. Extraction was done with hot water with the addition of β-mercaptoethanol. The infusions prepared from Lung-Ching teas (from the Zhejiang Province in China) contained the highest concentration of selenium in a typical cup of tea (12.5–17.3 µg L−1). For other tested teas it decreased in the following order: Yunnan > Dilmah > Lipton. For Lung-Ching teas, the sum of concentrations of SeMet and SeMetO corresponded to about 46–63% of the total selenium in their extracts.

Catechins and Selenium Species—How They React with Each Other

“…In parallel, a more significant decrease in selenomethionine content was determined, and traces of SeMetO appeared. The concentration of that selenium species with catechin was also decreasing at a prolonged The obtained results showed that SeMetO was included in the study due to the reported oxidation of selenomethionine [41][42][43][44]. The SeMet oxidation process, which takes place during sample extraction or storage, can be observed by the appearance of an additional chromatographic signal identified as SeMetO, with a simultaneous decrease in the intensity of the SeMet peak.…”

“…All of the commercial standards of selenium species used in the experiments (Na 2 SeO 3 (Se(IV)), Na 2 SeO 4 (Se(VI)), selenomethionine (SeMet), methylselenocysteine (MeSeCys), and selenocystine (SeCys 2 )) were purchased from Sigma-Merck (Steinheim, Germany). Selenomethionine oxide (SeMetO) was synthesized based on the previously described method [43]. Briefly, 1.00 mL of 30% (v/v) H 2 O 2 was added to 10.0 mL of an acidic solution of selenomethionine (10.00 mg L −1 ).…”

A Review of Plant Selenium-Enriched Proteins/Peptides: Extraction, Detection, Bioavailability, and Effects of Processing

“…Among them, HPLC has shown good adaptability for SeP separation [ 27 ], and it can be used to separate SePs from various types of plants, such as green tea [ 28 ] and radish sprouts [ 29 ]. Cubadda et al [ 30 ] used RP-IP-HPLC to separate wheat SePs after ultrasound-assisted enzymatic extraction, with final methionine Se and selenate accounting for 72–85% and 2–6% of the total Se content, respectively.…”

Preparative isolation of maltol glycoside from Dianthus superbus and its anti-inflammatory activity in vitro

“…Some researchers have employed hydrophilic interaction chromatography (HILIC) for polar compound purication from complex samples or as a means of providing complementary selectivity to an RPLC approach. 30,31 In this context, the coupling of RPLC and HILIC approaches represent an effective means of efficiently isolating bioactive compounds from various natural samples. [32][33][34] In this study, an effective method was utilized to isolate an anti-inammatory maltol glycoside from D. superbus by a combination of medium-and high-pressure liquid chromatography, which targeted in vitro anti-inammatory activity.…”

“…Some researchers have employed hydrophilic interaction chromatography (HILIC) for polar compound purification from complex samples or as a means of providing complementary selectivity to an RPLC approach. 30,31 In this context, the coupling of RPLC and HILIC approaches represent an effective means of efficiently isolating bioactive compounds from various natural samples. 32–34 …”