DOI: 10.5061/dryad.s4mw6m9h1
title: Comparison of benthic invertebrate body phosphorus determined by ICP-MS and colorimetry

description: Molybdenum blue colorimetry (MBC) is the dominant, well-established method
 used for determining total P in environmental media, including in
 organismal tissues. However, other elemental methods for P determination
 are available, including inductively coupled plasma mass spectrometry
 (ICP-MS). Given the extensive literature using MBC to determine P in
 organismal samples, it is important to assess P analyses by ICP-MS and MBC
 to ensure that the two methods produce comparable data. In this work, we
 compared ICP-MS and MBC for total P determination in freshwater
 invertebrates, including the potential for analytical interferences, by
 applying both methods to three standard reference materials (SRMs) and 106
 freshwater invertebrate samples. Average total P recoveries for SRMs were
 slightly higher for ICP-MS (99.8 ± 5.2%) than MBC (96.5 ± 5.4%), but both
 methods indicated good accuracy. Total P in invertebrates determined using
 the two methods was strongly linearly correlated (r = 0.96) with a slope
 of 1.01. On the whole, total P measured using ICP-MS exceeded that
 measured by MBC, but average pair-wise differences in %P were biologically
 negligible (0.044 ± 0.054). %P for SRMs and invertebrate samples run on
 ICP-MS in kinetic energy discrimination and standard modes compared
 favorably (e.g., SRM P recovery of 102% by both methods), indicating
 negligible influence of polyatomic ions on ICP-MS analysis. Similarly,
 analysis of P spike recoveries by ICP-MS (100.2 ± 3.4%) and MBC (107.0 ±
 2.8%) were both considered acceptable. We conclude that ICP-MS represents
 a reliable and comparable alternative to MBC for determining total P in
 freshwater invertebrates while also offering the opportunity to measure
 additional biologically relevant elements in a single analysis.
description: This dataset compares body %P data of freshwater invertebrates
 measured by ICP-MS and by the molybdenum blue colorimetric
 assay. 
description: # Costanza-Robinson et al. invertebrate P methods comparison data
 [https://doi.org/10.5061/dryad.s4mw6m9h1](https://doi.org/10.5061/dryad.s4mw6m9h1) ## Description of the data and file structure Body phosphorus data for freshwater benthic invertebrates associated with Costanza-Robinson et al. (Accepted) *Plos ONE.* ### Files and variables #### File: Costanza\_Robinson\_et\_al\_Pcomp\_data.xlsx **Description:** All data for standard reference materials and freshwater invertebrate samples used in the methods comparison. Some columns will contain NA values when that column is not pertinent to a given sample. For example, certified reference materials contain NA values for field sampling and taxonomic identification columns. All samples were not all used for the same set of analyses, so some %P columns and spike recovery columns will have NA values if that sample was not used in that analysis. ##### Variables * Sample Type: Denotes whether the sample is a standard reference material (SRM) or an unknown sample (NEON) * Sample ID: An internal sample ID unique to each sample * NEON Site: The name of the National Ecological Observatory Network aquatic site from which the sample was collected * Date Sampled: The date the sample was collected from the field * Order: The taxonomic order of the sampled organism * Family: The taxonomic family of the sampled organism * Genus: The taxonomic genus of the sampled organism * Dry_Wt_g: The dry mass of the sample that was digested and used for analysis (g) * BQL_MBC: Whether the sample was below the quantification limit using colorimetry (yes if so, otherwise blank) * BQL_ICPMS: Whether the sample was below the quantification limit using ICP-MS (yes if so, otherwise blank) * %P_MBC: The body %P of the invertebrate determined by colorimetry * %P_KED_ICPMS: The body %P of the invertebrate determined by ICP-MS in KED mode * %P_STD_ICPMS: The body %P of the invertebrate determined by ICP-MS in standard mode * %Recovery_totalP_MBC: Percent recovery of standard reference materials determined by colorimetry * %Recovery_totalP_KED_ICPMS: Percent recovery of standard reference materials determined by ICP-MS in KED mode * Pspike%Recovery_MBC: Percent recovery of P spiked in samples determined by colorimetry * Pspike%Recovery_KED_ICPMS: Percent recovery of P spiked in samples determined by ICP-MS in KED mode