Facilities & Instrumentation
LC-IRMS
Dionex UltiMate 3000 high performance liquid chromatograph (LC) coupled to a Thermo Fisher Delta V isotope ratio mass spectrometer (IRMS) via an LC-Isolink interface. The LC-IRMS performs online separation, quantification, and stable carbon isotopic characterization of organic molecular mixtures. In our lab, this instrument is used primarily for compound-specific isotopic analysis of benzenepolycarboxylic acids, which are molecular markers derived from condensed aromatic compounds (e.g., black carbon).
HPLC
Dionex UltiMate 3000 high performance liquid chromatograph (HPLC) equipped with an autosampler, quaternary pump, column oven, and photodiode array detector. The HPLC separates molecules in organic mixtures that are then identified and quantified by absorbance. In our lab, this instrument is used primarily for the high-throughput quantification of benzenepolycarboxylic acids, which are molecular markers derived from condensed aromatic compounds (e.g., black carbon). The stand-alone HPLC is also used for method development, where some methods could be transferred to the LC-IRMS for compound-specific analyses.
TOC/TDN Analyzer
Shimadzu TOC-L analyzer equipped with an autosampler and TNM-L unit. The TOC/TDN analyzer measures dissolved organic carbon and total dissolved nitrogen concentrations on filtered water samples. Since dissolved organic carbon concentrations are central to our research, every new water sample that comes through the door of our lab is analyzed using this instrument.
AQUALOG
Horiba Aqualog is used to measure the absorbance and fluorescence of dissolved organic matter. Absorbance is quantified in the UV-visible range (200 - 800 nm) and is used to calculate absorbance coefficients, specific UV absorbance (color per unit carbon), and spectral slopes. Fluorescence is typically measured as excitiation-emission matrices (EEMs), which is basically a 3D topographical map of the fluorescent character of dissolved organic matter. Variations in fluorescent “peaks” are used to infer changes in dissolved organic matter quality.
ULTRAPURE water system
Barnstead E-Pure water purification system cleans and converts tap water to ultrapure Type 1 water (resistivity = 18.2 MΩ-cm). This system is ideal for high-volume throughput and frequent use. In our lab, we use this water for nearly everything - From cleaning bottles and glassware to preparing analytical blanks and buffers.
other resources
Our lab space is also furnished with large drying and muffle ovens (cleaning glassware; sample prep), HP 5890 gas chromatograph oven (precise heating; sample oxidation), computers (GIS mapping; statistical analysis of large datasets), analytical balances, filtration apparatus, chemical hoods, and field sampling supplies (Nalgene bottles; coolers).
