Uremic Toxins Panel Quantification Service (PBUTs) — LC-MS/MS (MRM)

Background & Why Analyze Uremic Toxins

Protein-Bound Uremic Toxins (PBUTs): Why targeted quantification matters

PBUTs and related uremic solutes often show:

• Strong matrix effects (serum/plasma/urine/dialysate vary widely).
• Protein binding (total concentration may not reflect the diffusible portion).
• Broad dynamic range across subjects, timepoints, and interventions.

What problems we solve (research & industrial R&D)

• Convert relative signals into traceable absolute concentrations (μM / ng/mL) for robust statistics, modeling, and reporting.
• Support Free vs Total PBUTs study designs to quantify protein-binding effects and to compute Free fraction (%).
• Provide batch QA/QC documentation so your quantitative conclusions are reproducible and defensible across large studies.

What We Offer: Uremic Toxins Targeted Quantification Services

Core Quantification

Absolute quantification of key uremic toxins, including indoxyl sulfate, p-cresyl sulfate, and IAA, using LC-MS/MS (MRM).

Delivered as structured panel output with concentration values (μM or ng/mL), LOQ-aware flags, and batch-level QA/QC.

Customizable Panels

Extendable to include gut-derived aromatic acids, conjugated metabolites, and co-factors (e.g., hippuric acid, phenyl sulfate, ADMA, TMAO). Feasibility assessed based on matrix, target list, and expected range

Optional Modules

• Free vs Total quantification: Includes free concentration, total concentration, and Free fraction (%)
• Extended dynamic range or high-sensitivity setup for low-abundance targets
• Cross-batch harmonization for longitudinal or multi-cohort projects

Detectable Analytes: Uremic Toxins Panel List

Final panel can be Core only or Core + Extensions, and is customizable based on your study and matrix.

Custom list welcome: If your target analytes are not listed, send the list + matrix + expected range. We will confirm feasibility and propose an optimized panel.

Quantitative Performance & Data Quality Highlights

• Absolute concentration outputs (μM / ng/mL) with LOQ-aware flags suitable for statistics and modeling.
• Selectivity for closely related metabolites via MRM transitions (quantifier + qualifier) and retention-time checks.
• Typical precision targets: intra-/inter-batch CV commonly ≤15% (low-level points may be ≤20%; matrix/analyte dependent).
• Typical calibration performance targets: weighted regression with R² ≥ 0.99 (panel- and matrix-dependent).
• Dynamic range built for cohort studies: commonly 2–4 orders of magnitude depending on analyte and matrix.
• Optional Free vs Total PBUTs: outputs Free, Total, and Free fraction (%) for PBUT-focused designs.

Analytical Workflow for Targeted Uremic Toxins Analysis

1

Study intake

Targets, matrix, sample number, timepoints, expected range, Free/Total requirement

2

Feasibility & plan

Standards/internal standard strategy, sample prep route, calibration & QC design

3

Sample receiving

Manifest check, condition logging, storage verification

4

Sample preparation

Total: protein precipitation / cleanup (SPE when needed)

Free (optional): ultrafiltration/separation workflow with controlled conditions

5

LC-MS/MS acquisition (MRM)

Batch sequence includes blanks, calibrators, QCs, and study samples

6

Data processing & QA/QC

Integration rules, ion ratio checks, drift review, LOQ handling

Analytical Platforms for PBUTs / Uremic Toxins Quantification

Our PBUTs panel analysis is performed on an Agilent 1290 Infinity II UHPLC system coupled with an Agilent 6495C Triple Quadrupole Mass Spectrometer, optimized for high-sensitivity targeted quantification in complex matrices (e.g., plasma, serum, urine, dialysate).

Key Instrument Parameters

Instrument configuration ensures accurate detection of low-abundance PBUTs with minimized matrix interference and high reproducibility.

Agilent 1290 Infinity II HPLC (Figure from Agilent)

Agilent 6495C Triple quadrupole (Figure from Agilent)

Sample Types & Submission Requirements

We accept the following sample types for PBUTs and related uremic solutes quantification:

Additional Notes:

• Limit freeze–thaw cycles to ≤2
• Provide a complete sample manifest: sample ID, matrix, volume, group, collection timepoint
• Animal samples (e.g., rat/mouse plasma, urine) are accepted upon request
• Fecal samples may be accepted for specific precursor analysis — contact us for feasibility evaluation

Deliverables: Quantitative Data Package and QC Report

• Quantification results table (Excel/CSV): absolute concentrations (μM and/or ng/mL) per analyte per sample + LOQ flags.
• Free/Total table (Excel/CSV, if selected): Free, Total, and Free fraction (%).
• Batch QC report (PDF): calibration summary + QC performance + carryover check.
• Peak integration export (Excel/CSV): RT, transitions, peak areas/ratios, integration flags.
• MRM transition list (Excel/PDF): quantifier/qualifier transitions + RT windows.
• Sample receipt log (Excel/PDF): manifest check + condition notes.
• Raw data files (on request): vendor raw ± mzML.
• Methods summary (PDF): prep overview + key parameters + LOQ rules.

Representative LC–MS/MS MRM chromatograms for IS, pCS, IAA, and HA in matrix: sample, calibrator, and blank overlaid with RT window shading and quantifier/qualifier transitions.

Weighted calibration curves with LOQ markers and aligned residual (or accuracy) plots versus concentration for targeted LC–MS/MS quantification of uremic-toxin analytes.

Applications in PBUTs and Uremic Toxin Quantification Research

CKD & Uremia Mechanism Research

Quantify PBUTs (IS, pCS, IAA) and related solutes across groups/timepoints to study gut-derived metabolic shifts and kidney excretory dysfunction.

Dialysis Efficacy & Kinetics

Measure pre/post-dialysis and rebound concentrations (e.g., 0 h / 2 h / 24 h) to assess clearance efficiency and kinetic profiles.

Membrane / Sorbent / Adsorbent Development

Compare Total vs Free PBUT levels to evaluate adsorption performance and protein-binding limitations of new dialysis materials.

Microbiome & Dietary Interventions

Track changes in indole/phenyl metabolites and their conjugates to assess microbial or nutritional modulation of uremic toxin pathways.

Drug / Nutraceutical Screening

Use absolute PBUT concentrations as pharmacodynamic endpoints in preclinical or human studies to evaluate metabolic response.

Cohort Studies & Multi-omics Integration

Generate standardized quantitative features for association analysis and integration with metagenomics, transcriptomics, or proteomics.