Leaf Wax Lipid Extraction for Archaeological Applications

Abstract

Plant wax lipid molecules, chiefly normal (n‐) alkanes and n‐alkanoic acids, are frequently used as proxies for understanding paleoenvironmental and paleoclimatic change. These are regularly analyzed from marine and lake sediments and even more frequently in archaeological contexts, enabling the reconstruction of past environments in direct association with records of past human behavior. Carbon and hydrogen isotope measurements of these compounds are used to trace plant type and water‐use efficiency, relative paleotemperature, precipitation, evapotranspiration of leaf and soil moisture, and other physiological and ecological parameters. Plant wax lipids have great potential for answering questions related to human‐environment interactions, being for the most part chemically inert and easily recoverable in terrestrial sediments, including those dating back millions of years. The growing use of this technique, and comparison of such data with other paleoenvironmental proxies such as pollen and phytolith analysis and soil carbonate and tooth enamel isotope records, make it essential to establish consistent, best‐practice protocols for extracting n‐alkanes and n‐alkanoic acids from archaeological sediments to provide comparable information for interpreting past climatic, ecosystem, and hydrological changes and their interaction with human societies. © 2020 The Authors. Basic Protocol 1: Total lipid extraction Support Protocol 1: Weighing the total lipid extract Support Protocol 2: Cleaning the PSE extraction cells Alternate Protocol 1: Soxhlet total lipid extraction Alternate Protocol 2: Ultrasonic total lipid extraction Basic Protocol 2: Separation of lipids by aminopropyl column chromatography Basic Protocol 3: Separation of lipids by silver‐nitrate‐infused silica gel column chromatography Support Protocol 3: Preparation of silica gel infused with 10% silver nitrate Basic Protocol 4: Methylation of n‐alkanoic acids Basic Protocol 5: Gas chromatography mass spectrometry (GC‐MS) Basic Protocol 6: Gas chromatography isotope ratio mass spectrometry (GC‐IRMS)

Potential impact of Holocene climate changes on camel breeding practices of Neolithic pastoralists in the Central Asian drylands: A preliminary assessment

“…The obtained 35 mL of the total lipid extract (TLE) were evaporated under nitrogen stream, weighted and re-dissolved in 1 mL n -hexane. TLE was separated into fractions of different polarities on a Pasteur pipette conditioned at 500 o C and filled with high-purity silica gel (60 Å pore, Sigma Aldrich) activated for 8 h at 120°C (Patalano et al, 2020). n-Hexane fraction was obtained as the first, DCM fraction as the second and MeOH fraction as the third.…”

“…Lipid analysis and interpretations followed protocols established in (Sachse et al, 2004) and (Patalano et al, 2020). All reagents and solvents used were of analytical grade (HPLC, >95% of purity).…”

Untitled

“…Fabrics are usually hard-fired and surfaces may be burnished or well smoothed. This category shows several macroscopic characteristics of the pottery traditionally known as 'Yellow Minyan', 57 also detected in the 'Yellow and Red Minyan' wares of central Greece 58 and in the long-lasting 'Hard Orange' wares of the southwestern Peloponnese. 59 The definition of this group also partially overlaps that of the 'Argive Light' wares described by Dietz.…”

“…57 The pot graves contained burials of infants and children, while the remains of an adult female individual, in this case cremated, were found only in Grave K. Two burial vessels (Graves K and AĞ) can be described as handleless globular jars with an everted rim, one is a bowl (Grave AM), while one is a wide-mouthed jar (Grave Bİ). 58 One of the burial vessels (Grave AÇ) discovered at the North cemetery is a krater. 59 It is important to note that the wide-mouthed jar of Grave Bİ resembles a krater, as noted by Blegen, Caskey and Rawson for some of the examples at Troy.…”

Plant wax biomarkers in human evolutionary studies

“…Compound‐specific isotope analyses on individual n ‐alkanes (e.g., C 31 ) or n ‐alkanoic acids (e.g., C 30 ) also erases the ambiguity in isotope measurements inherent in bulk sediment isotope analysis. Lastly, from a sample processing perspective, biomarker analysis is less time consuming than pollen or phytolith extractions, which require extensive preparation and count time; though isotope measurements can become expensive due to the need to analyze δ 13 C at least in duplicate and δD in triplicate 44 …”