Analysis of cooking spices in natural waters

Abstract

An isolation and quantification technique is presented for the analysis of semi-volatile spices and scents in aquatic waters including thymol, eugenol, limonene, carvacrol, vanillin, and cinnamaldehyde. Compounds are isolated from natural waters by solid phase extraction onto Waters Oasis HLB columns and eluted into ethyl acetate. Recovery efficiencies are >70% for most target compounds. Comparison with liquid-liquid extraction and C-18 solid phase extraction indicates that HLB cartridges are more robust and provide equal or better recoveries for target compounds relative to other approaches. Because the compounds are semi-volatile and prone to losses during solvent evaporation, we do not dry the samples completely before quantification by gas chromatography mass spectrometry. Compounds are analyzed using selected ion monitoring with a sensitivity ~1 pg compound per injection. This equates to a sensitivity of about 2-200 ng L -1 in natural waters, or part-per-billion levels. Column loading and matrix effects are minimal and are accounted for by careful monitoring of volumes and by standard additions during GC analysis. Environmental samples (treated sewage, lake, stream, and fjord samples) show a wide range of compounds and quantities, most in the 10-10,000 ng L -1 range. The artificial spice ethylvanillin, which is commonly used as an internal standard in analysis of woody lignin samples, is found in some natural waters. This is likely a result of the industrial-scale production of this compound for culinary and pharmaceutical use.

The compositional evolution of dissolved and particulate organic matter along the lower Amazon River—Óbidos to the ocean

“…Dissolved lignin samples were filtered through 142 mm diameter Whatman GF/F glass fiber filters and 142 mm Pall Supor membrane filters (0.2 μm pore-size), acidified to pH 2 with HCl, extracted at 3 mL/ min on Waters Oasis HLB solid phase extraction cartridges (6 cm 3 volume, 200 mg sorbent), and frozen (Keil and Neibauer, 2009). 500 to 1000 mL of water was passed through each cartridge depending on the abundance of DOC.…”

Differential effects of solid‐phase extraction resins on the measurement of dissolved lignin‐phenols and organic matter composition in natural waters

“…In this study, we build on previous findings from Dittmar et al (), Spencer et al (), and Keil and Neibauer () to better explore the effects of DOM isolation techniques on the optical properties and quantification of dissolved LOPs, naturally free‐lignin phenols, and the resultant diagnostic ratios. More specifically, and for the first time to our knowledge, we investigate the fractionation effects of C‐18, HLB, and PPL cartridges on the abundance and distribution of free/unbound and polymeric lignin phenols within both riverine and coastal/saline matrices.…”

“…Recent work has shown that the extraction of dissolved organic matter (DOM) via solid‐phase extraction (SPE) is biased toward specific functional groups, molecular size and/or conformations, thereby affecting all subsequent analyses, such as bulk carbon, biomarker, and spectroscopy measurements (Spencer et al ; Chen et al ; Raeke et al ; Li et al ). Much of this previous work has been on the bulk carbon of DOM, with very few studies examining fractionation effects on naturally occurring dissolved lignin phenols and lignin oxidization products (LOPs) (Keil and Neibauer ; Spencer et al ).…”

“…However, for freshwater systems, all three techniques were comparable in recovering lignin LOPs. Keil and Neibauer () found that hydrophile‐lipophile balance (HLB) sorbents obtain equal or better recoveries of free monomeric lignin phenols compared to C‐18 sorbents and liquid‐liquid extraction in various aquatic environments. Another common SPE cartridge, the styrene divinyl benzene polymer (PPL) cartridge, was found to more efficiently extract marine DOM than C‐18 cartridges (Dittmar et al ) and is widely used for ultrahigh‐resolution mass spectrometry (Kellerman et al ; Roth et al ; Lechtenfeld et al ; Li et al ; Raeke et al ).…”

Fragrances as new contaminants in the Venice lagoon

“…On the basis of literature and existing methods Keil and Neibauer, 2009;Peck, 2006;Simonich et al, 2000;Vecchiato et al, 2015), different solvents and aliquots were tested for the elution of the FMs from the SPE cartridges and the final procedure derives from the combination of the most effective ones. Cartridges were not dried under vacuum in order to prevent possible losses of the more volatile analytes.…”