Varying matrix effects for elemental analysis identified from groundwater in the Barnett Shale|
Carlton Jr., D. D.; Fontenot, B. E.; Hildenbrand, Z. L.; Davis, T. M.; Walton, J. L. & Schug, K. A.
The quality of analytical measurements can be
influenced by the matrix of the sample of interest. The
knowledge of the sample matrix allows for appropriate
sample preparation, instrumental parameters, and quantification
methods in an effort to achieve accurate results.
Matrix matching can be difficult when sampling across
various water sources with the possible introduction of
unknown endogenous contaminants due to various degrees
of land use, urbanization, and energy exploration, likely
playing a factor. The degree of matrix effects in inductively
coupled plasma–optical emission spectroscopy for nineteen
metals from twenty groundwater samples across North
Texas was assessed using a standard addition method.
Matrix effects were characterized in collected groundwater
samples (a) with no pretreatment, (b) after reversed-phase
solid-phase extraction of possible organic contaminants,
and (c) for a matrix of organic material retained on the
reversed-phase sorbent. It was found that without any extraction
treatment, only 54 % of all measurements
experienced no matrix effect. After extracting unknown
organic sample constituents, an increase to 74 % of measurements
showing no matrix effect was recorded. Reconstituting
the extracted organic sample matrix found this
fraction to be a significant source of the deviated results
with only 13 % experiencing no matrix effect. Results for
the metals investigated are also discussed, along with
correlations to water quality parameters such as turbidity,
total dissolved solids, and salinity.
Inductively coupled plasma–optical emission spectroscopy; Solid-phase extraction; Sample preparation; Unconventional drilling