Adapting the Accelerated Solvent Extraction Method for Resin and Rubber Determination in Guayule Using the BÜCHI Speed Extractor

Abstract

Guayule (Parthenium argentatum Gray) is a promising alternative source to Hevea brasiliensis for the production of natural rubber, which can reach levels of 8–9% under industrialized farming conditions. The most common method for determining rubber concentration is by accelerated solvent extraction (ASE), a technique developed by the Dionex Corporation and almost exclusively performed with the Dionex ASE-200 or 350 systems. Herein, it is sought to apply and adapt the most common methods used in the literature for the Dionex system to another extraction platform, the BÜCHI Speed Extractor E-914. Results showed that using a sand sandwich method to confine the sample in the center and exploiting a larger cell volume (80 mL) for extraction prevents the occurrence of overpressure and problems with clogging. Under optimized conditions, the coefficient of variation was <15% for both resin quantification for samples containing 5.0–15.8% of resin and for rubber quantification for samples with 1.7–10.3% rubber content. The extraction time for resin (2 cycles of 5 min each) was smaller than for rubber (2 cycles of 20 min each). It would be interesting to carry out interlaboratory comparisons to standardize the method at an international level.

Composition of Guayule (Parthenium argentatum Gray) resin

“…Acetone extracts are collected in 120 mL vials and then transferred into round-bottom flasks in order to evaporate the acetone, first with Rotavap (BUCHI) and then dried at 50 °C in a laboratory convection oven (Binder) to constant weight. Once weighed, the dried acetone extract is diluted with acetone to obtain a 10 mg/mL solution and stored in the freezer (− 20 °C) until analysis 28 . The dry extract is call “ASE resin”.…”

Development of a microwave‐assisted solvent extraction process for the extraction of high‐value carotenoids from Chlorella biomass

“…n ‐Hexane is commonly microwave transparent and is used to elute nonpolar carotenoids and esterified xanthophylls. It also helps to protect the carotenoid compounds, which are generally thermolabile 27 . Ethanol and methanol were selected for their heat absorption efficiency and high dissipation factors on microwave exposure, which would add to the increase in yield.…”

“…It also helps to protect the carotenoid compounds, which are generally thermolabile. 27 Ethanol and methanol were selected for their heat absorption efficiency and high dissipation factors on microwave exposure, which would add to the increase in yield. These solvents, individually or in mixtures, exposed to microwave power absorption with their innate physicochemical properties should normally provide higher extraction results.…”

Evaluating Guayule (Parthenium argentatum A. Gray) Germplasm Grown in Spain: Rubber and Resin along Three Production Cycles

“…A cellulose acetate filter was placed at the top and bottom of each cell to avoid sample contamination. The extraction conditions have been described in detail previously [ 33 ]. The resins and rubber extracts were collected in 250 mL flasks and transferred to pre-weighed flasks.…”