LC-MS/MS Scientific Resource
Choosing Biological Matrices for Assay Development
How to Select Serum, Plasma, Urine, Specialty, and Low-Analyte Matrices
A practical guide for LC-MS/MS, immunoassay development, calibration, controls, and analytical validation.
Biological matrix selection can influence extraction recovery, ionization, calibration response, analyte stability, and overall assay performance. The most appropriate matrix depends on the intended specimen type, analyte concentration range, analytical platform, and development objective.
Monobind offers human serum and plasma, urine, albumin, IGIV, specialty matrices, and low-analyte materials with multiple processing options to support research, diagnostic development, calibration, controls, and quantitative LC-MS/MS workflows.
Start with the Intended Specimen Type
Human Serum & Plasma
Appropriate when the assay is intended to measure serum- or plasma-based specimens. Processing options may be selected to modify endogenous analyte, lipid, protein, or other matrix characteristics.
Human Urine
Useful for toxicology, drug testing, metabolite analysis, and other urine-based methods where the calibration or control matrix should reflect the intended sample type.
Human Albumin
Available in liquid and lyophilized formats and useful when a controlled protein-based matrix or reagent background is preferred.
Specialty & Low-Analyte Matrices
Designed for applications requiring reduced endogenous analyte, modified matrix composition, or specialized calibration characteristics.
Consider the Endogenous Analyte Level
Native biological matrices may contain measurable concentrations of the target analyte. For low-level calibration or highly sensitive methods, this background can interfere with establishing the desired baseline.
✓ Native serum or plasma for representative specimen behavior
✓ Charcoal-stripped material for reduced small-molecule background
✓ Resin-stripped material for selected analyte reduction
✓ Delipidated material where lipid content is a concern
✓ Specialty depleted matrices for defined analyte targets
✓ TrueZero® for ultra-low analyte applications
Match Matrix Processing to the Analytical Need
Defibrinated
Removes fibrin-related material while maintaining a biologically derived serum or plasma background.
Charcoal Stripped
Used when reduction of selected small molecules or endogenous analytes is desirable.
Resin Stripped
Provides an alternative stripping approach for methods requiring reduction of selected endogenous components.
Delipidated
Reduces lipid content where lipid-associated interference, background, or matrix behavior is a concern.
How Matrix Processing Changes the Material
Different processing methods reduce specific endogenous components and can help create a matrix better suited to the intended analytical application.
| Process | Primarily Reduces | Potential Useful Application |
|---|
| Charcoal Stripping | Steroid hormones and other small hydrophobic molecules | Low-background hormone or small-molecule calibration and assay development |
| Resin Stripping | Thyroid hormones and selected charged endogenous compounds | Thyroid assay calibration, controls, and low-thyroid-analyte matrices |
| Delipidation | Lipids and lipid-associated material | Reduce lipid-related interference or create a lower-lipid biological matrix |
| Charcoal + Delipidation | Steroid / small-molecule background and lipids | Low-background hormone or LC-MS/MS development where lipid interference may also matter |
| Resin + Delipidation | Thyroid-related analytes and lipids | Thyroid-focused calibration or controls requiring reduced lipid content |
| Defibrination | Fibrinogen and clot-forming material | Serum-like matrix applications where reduced fibrin or clotting interference is preferred |
Processing reduces selected endogenous components; actual residual concentrations vary by material, process, and lot. Monobind provides a Certificate of Analysis for each lot and can custom-produce materials to defined specifications, including analyte profile and protein concentration, for evaluation in the intended method.
Examples of Specialty Matrix Options
Monobind offers specialty materials developed for specific analyte backgrounds and calibration needs.
✓ Vitamin D Free Matrix
✓ Protein Calibrator Matrix
✓ 15% T-Uptake Matrix
✓ Low Vitamin B12 Matrix
✓ Thyroid Calibrator Matrix
✓ Low Anti-Tg/TPO Matrix
✓ HCY Depleted Matrix
✓ Custom specialty matrix development
Ultra-Low Analyte Matrices
When to Consider TrueZero®
TrueZero® materials are designed for applications requiring an ultra-low analyte background, including sensitive immunoassays and LC-MS/MS workflows.
TrueZero® Human Serum – Ultra-Low Hormone & Steroid, Lipid Free
TrueZero® Human Serum – Ultra-Low Vitamin D, Lipid Free
Choosing a Urine Matrix
Urine-based methods should use a matrix that reflects the intended analytical application and desired background characteristics.
✓ Drug-Free Human Urine, Raw & Pooled
✓ Drug-Free Urine Matrix, pH Treated
✓ Drug-Free Urine Matrix, Sodium Azide / pH Treated
✓ Drug-Free EtG/Cotinine Urine Matrix
Consider Format, Scale, and Consistency
✓ Liquid vs. lyophilized format
✓ R&D aliquot vs. bulk production volume
✓ Pooled vs. sex-specific material
✓ Preservative requirements
✓ Lot-to-lot consistency
✓ Target analyte profile and concentration
✓ Protein concentration and matrix composition
✓ Custom processing or specification requirements
Practical Matrix Selection Checklist
✓ What specimen type will the method measure?
✓ What is the endogenous concentration of the target analyte?
✓ Is a native, depleted, stripped, or surrogate matrix needed?
✓ Could lipids, proteins, salts, or metabolites affect performance?
✓ Does the matrix behave comparably during extraction?
✓ Does the matrix produce representative ionization behavior?
✓ Is the material appropriate for calibrators, controls, or both?
✓ Is lot consistency adequate for the intended development program?
Key Takeaways
✓ Start with the intended specimen type.
✓ Consider endogenous analyte background.
✓ Use stripping or depletion when lower background is required.
✓ Evaluate matrix effects and extraction behavior.
✓ Match matrix format to the intended application and scale.
✓ Validate comparability before finalizing the method.
Related Scientific Resources
Related Biomaterial Solutions
Find the Matrix That Fits Your Method
Explore human serum and plasma, urine, albumin, specialty matrices, TrueZero® low-analyte materials, and custom processing options for assay development and analytical validation.
Request a Matrix for Your Application
Tell us your target analyte, matrix type, approximate volume, and application. Our team can help identify an appropriate TrueZero®, specialty, or human biological matrix for evaluation.
This educational resource is intended to support assay developers, clinical laboratories, and research scientists. Matrix selection, calibration design, and analytical validation should be based on the specific requirements of each method and its intended use.
