Rapid Extraction Technique Prepares Urine Samples for Mass Spectrometry Analysis
By LabMedica International staff writers Posted on 07 Jun 2015 |
Image: The centrifugation step is the key to removing protein biomarkers from urine\'s high salt matrix (Photo courtesy of Clemson University).
Disposable mini-tubes packed with capillary-channeled polymer (C-CP) fibers have been adapted for the rapid extraction of proteins from urine specimens for analysis by MALDI-MS (matrix-assisted laser desorption/ionization mass spectrometry).
While mass spectrometry is a powerful tool for biomarker determinations, the high salt content and the matrix of small molecules present in urine has reduced its applicability for urinary diagnosis. To correct this deficiency, investigators at Clemson University (SC, USA) packed micropipette tips with C-CP fibers. These fibers possess a unique geometry that includes eight channels that extend the entire fiber length (which can be miles on a spool). The fibers are nominally an oblong shape with diameters ranging from 35 to 50 micrometers, with the individual channels ranging in size from five to 20 micrometers.
Urine samples were passed through fiber-packed tubes by spinning them in a centrifuge for 30 seconds. Following centrifugation de-ionized water was run through the tubes for one minute to wash off salt and other contaminants. Hydrophobic proteins, which remained bound to the fibers, were extracted for MALDI-MS analysis with appropriate solvents during a 30 second centrifugation step.
Matrix-assisted laser desorption/ionization (MALDI) is a soft ionization technique used in mass spectrometry, allowing the analysis of biomolecules (biopolymers such as DNA, proteins, peptides, and sugars) and large organic molecules (such as polymers, dendrimers, and other macromolecules), which tend to be fragile and fragment when ionized by more conventional ionization methods. It is similar in character to electrospray ionization (ESI) in that both techniques are relatively soft ways of obtaining ions of large molecules in the gas phase, though MALDI produces far fewer multiply charged ions.
The C-CP fiber method was validated by measuring the urinary proteins beta-2-microglobulin, retinol binding protein, and transferrin. C-CP fiber tips offered several advantages including low materials costs, high throughput, microvolume processing, and the determination of sub-nanogram quantities of analyte; allowing determination of biomarkers that are otherwise undetectable in urine samples.
"You have got almost seawater coming out of you, and I am trying to find something far smaller than a needle in a haystack," said senior author Dr. Ken Marcus, professor of analytical chemistry at Clemson University. "The concentrations of these proteins would be one part in a billion."
The C-CP fiber method for urine sample purification was described in the March 18, 2015, online edition of the journal Proteomics-Clinical Applications.
Related Links:
Clemson University
While mass spectrometry is a powerful tool for biomarker determinations, the high salt content and the matrix of small molecules present in urine has reduced its applicability for urinary diagnosis. To correct this deficiency, investigators at Clemson University (SC, USA) packed micropipette tips with C-CP fibers. These fibers possess a unique geometry that includes eight channels that extend the entire fiber length (which can be miles on a spool). The fibers are nominally an oblong shape with diameters ranging from 35 to 50 micrometers, with the individual channels ranging in size from five to 20 micrometers.
Urine samples were passed through fiber-packed tubes by spinning them in a centrifuge for 30 seconds. Following centrifugation de-ionized water was run through the tubes for one minute to wash off salt and other contaminants. Hydrophobic proteins, which remained bound to the fibers, were extracted for MALDI-MS analysis with appropriate solvents during a 30 second centrifugation step.
Matrix-assisted laser desorption/ionization (MALDI) is a soft ionization technique used in mass spectrometry, allowing the analysis of biomolecules (biopolymers such as DNA, proteins, peptides, and sugars) and large organic molecules (such as polymers, dendrimers, and other macromolecules), which tend to be fragile and fragment when ionized by more conventional ionization methods. It is similar in character to electrospray ionization (ESI) in that both techniques are relatively soft ways of obtaining ions of large molecules in the gas phase, though MALDI produces far fewer multiply charged ions.
The C-CP fiber method was validated by measuring the urinary proteins beta-2-microglobulin, retinol binding protein, and transferrin. C-CP fiber tips offered several advantages including low materials costs, high throughput, microvolume processing, and the determination of sub-nanogram quantities of analyte; allowing determination of biomarkers that are otherwise undetectable in urine samples.
"You have got almost seawater coming out of you, and I am trying to find something far smaller than a needle in a haystack," said senior author Dr. Ken Marcus, professor of analytical chemistry at Clemson University. "The concentrations of these proteins would be one part in a billion."
The C-CP fiber method for urine sample purification was described in the March 18, 2015, online edition of the journal Proteomics-Clinical Applications.
Related Links:
Clemson University
Latest Clinical Chem. News
- 3D Printed Point-Of-Care Mass Spectrometer Outperforms State-Of-The-Art Models
- POC Biomedical Test Spins Water Droplet Using Sound Waves for Cancer Detection
- Highly Reliable Cell-Based Assay Enables Accurate Diagnosis of Endocrine Diseases
- New Blood Testing Method Detects Potent Opioids in Under Three Minutes
- Wireless Hepatitis B Test Kit Completes Screening and Data Collection in One Step
- Pain-Free, Low-Cost, Sensitive, Radiation-Free Device Detects Breast Cancer in Urine
- Spit Test Detects Breast Cancer in Five Seconds
- Electrochemical Sensors with Next-Generation Coating Advances Precision Diagnostics at POC
- First-Of-Its-Kind Handheld Device Accurately Detects Fentanyl in Urine within Seconds
- New Fluorescent Sensor Array Lights up Alzheimer’s-Related Proteins for Earlier Detection
- Automated Mass Spectrometry-Based Clinical Analyzer Could Transform Lab Testing
- Highly Sensitive pH Sensor to Aid Detection of Cancers and Vector-Borne Viruses
- Non-Invasive Sensor Monitors Changes in Saliva Compositions to Rapidly Diagnose Diabetes
- Breakthrough Immunoassays to Aid in Risk Assessment of Preeclampsia
- Urine Test for Monitoring Changes in Kidney Health Markers Can Predict New-Onset Heart Failure
- AACC Releases Comprehensive Diabetes Testing Guidelines