Improvement in determination of isothiocyanates using high‐temperature reversed‐phase HPLC

Abstract

The largely adopted reversed-phase HPLC analysis of the molecular species of isothiocyanates (ITCs) was performed and showed losses during the chromatographic run with eight ITCs. These losses, which obviously impact the accuracy of quantitative determinations, were due to precipitation in the chromatographic system. At 22°C, they ranged from 5.4% for sulforaphane (SFN) to 11.0% for benzyl-ITC when ITCs were injected at 80 μg mL(-1) , but they were up to three times higher at 1 mg mL(-1) reaching 31.9% for benzyl-ITC. The water solubility of the ITCs was a key determinant of the extent of the measured loss. When the column was heated at 60°C, losses in injected ITCs were reduced, in comparison with 22, 40, and 50°C, by two to ten times depending on the ITC considered. A reversed-phase HPLC method based on column heating was suggested and its quantitative performance was determined. It was then applied to the separation of methylene chloride extracts of various cruciferous vegetables. Ally-ITC, SFN, and iberin in cabbage; SFN and iberin in cauliflower; and allyl-ITC and phenylethyl-ITC in horseradish could be identified and quantified. The obtained results cast doubt on quantitative determinations of ITCs that are carried out at room temperature using reversed-phase HPLC.

Chemopreventive glucosinolate accumulation in various broccoli and collard tissues: Microfluidic-based targeted transcriptomics for by-product valorization

“…This discrepancy is probably due to its lower solubility in water compared to other compounds, which has been previously reported [ 19 , 26 ]. Although SF has a water solubility of 8.0 mg/mL, PEITC has only 0.051 mg/mL of water solubility [ 27 ]. For by-product utilization, lack of water solubility of PEITC should be considered as an important factor.…”

The antibacterial properties of isothiocyanates

“…A recently improved HPLC method identified AITC and PEITC as the two main horseradish ITCs, whereas iberin and SFN were at a concentration below the detection limit. Iberin and SFN were, however, detected in both cauliflower and cabbage (Wilson et al, 2012). Iberin (3-methylsulfinylpropyl ITC) is an analogue of SFN, differing only in a shorter lateral chain (Table 1).…”

The Role of Glucosinolate Hydrolysis Products from Brassica Vegetable Consumption in Inducing Antioxidant Activity and Reducing Cancer Incidence

“…The high bioavailability of PEITC, much like SF, contributes to the promise of this phytochemical being absorbed in effective doses through dietary means. A disadvantage of PEITC compared to SF is that this compound is much more volatile [161], less water soluble [162], and therefore more likely to be lost from the Brassica vegetable during preparation ( i.e. , after cutting of plant tissue leads to hydrolysis of gluconasturtiin, the precursor GS of PEITC).…”