Comparison of benthic invertebrate body phosphorus determined by ICP-MS and colorimetry

Moody, Eric 1 ; Costanza-Robinson, Molly1

Published Jan 13, 2025 on Dryad. https://doi.org/10.5061/dryad.s4mw6m9h1

Data files

Jan 13, 2025 version files 31.51 KB

Costanza_Robinson_et_al_Pcomp_data.xlsx
29.13 KB
README.md
2.38 KB

Abstract

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.

README: Costanza-Robinson et al. invertebrate P methods comparison data

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