ABSTRACT
In this data article, we present the spectroscopic structural data of the pottery samples collected from Petén Itzá, Guatemala. Detailed Fourier transmission infrared, powder X-ray diffraction, scanning electron microscopy coupled to electron dispersive X-ray diffraction, and thermal gravimetric analysis/differential thermal gravimetric analysis (FTIR, PXRD, SEM/EDX, and TGA/DTGA) were discussed in the research article titled "Comprehensive Structural and Compositional Investigation of Maya Pottery Sherds from Lake Petén Itzá, Guatemala, Central America" (Onchoke et al. 2020 [1]). The FTIR, XRD profiles and composition of pottery from Petén Itzá, Guatemala are presented. This data is important and useful for further understanding of the structural composition of pottery sherds used by Maya people of Guatemala. In addition, the TGA/DTGA profiles provide information on the content of the losses upon heating and offers supportive evidence to the spectroscopic data studied.
ABSTRACT
Volatile organic compounds released from the biosphere are known to have a large impact on atmospheric chemistry. Field instruments for the detection of these trace gases are often limited by the lack of instrument portability and the inability to distinguish compounds of interest from background or other interfering compounds. We have developed an automated sampling and preconcentration system, coupled to a lightweight, low-power cylindrical ion trap mass spectrometer. The instrument was evaluated by measuring isoprene concentrations during a field campaign at the University of Michigan Biological Station PROPHET lab. Isoprene was preconcentrated by sampling directly into a short capillary column precooled without the aid of cryogens. The capillary column was then rapidly heated by moving the column to a preheated region to obtain fast separation of isoprene from other components, followed by detection with a cylindrical ion trap. This combination yielded a detection limit of approximately 80 ppt (parts per trillion) for isoprene with a measurement frequency of one sample every 11 min. The data obtained by the automated sampling and preconcentration system during the PROPHET 2005 campaign were compared to those of other field instruments measuring isoprene at this site in an intercomparison exercise. The intercomparisons suggest the new inlet system, when coupled with this ion trap detector, provides a viable field instrument for the fast, precise, and quantitative determination of isoprene and other trace gases over a variety of atmospheric conditions.
