Researchers investigated the use of electric field in dried blood spot (DBS) sample preparation for the detection of steroids in newborns using liquid chromatography-tandem mass spectrometry (LC-MS/MS) using both regular electroporation cuvettes and a custom vial setup.
A recent study (1) published in the journal Advanced Sample Preparation presented the use of liquid chromatography-tandem mass spectrometry (LC-MS/MS) as a driver for sample preparation from dried blood spot (DBS) samples to quantify the steroids testosterone (T), 17α-hydroxyprogesterone (17-OHP), progesterone (P), and cortisol (C), simultaneously. This method uses both standard electroporation cuvettes, as well as a novel custom vertical electric field setup. The findings, backed by computational modeling, reveal that a 10V DC application for 180 s will draw out double the amount of the previously mentioned steroids from sample collection cards when using the authors’ proprietary device as opposed to any standard collection methods which are solvent-based. The study presents the application of electric field for metabolomic sample preparation, as well as a discussion pertaining to a unique device which eliminates the electric double layer effect in the process.
A similar study, authored by two of the same authors, John Murphy and Anubhav Tripathi (2), discuss the establishment of a DBS extraction method using the synergistic action of electrophoretic and diffusive transport mechanisms to extract genomic DNA (gDNA) through the DBS matrix. The method (dubbed "Electro-DBS" by its creators) reduces extraction time from 40 min to 5 min, negating the need for heat, shaking, and DNA purification steps, yet still maintaining the yield and quality of gDNA extracted. The authors discovered that the electrophoretic transport speeds up the elution of gDNA, allowing the diffusive transport of polymerase chain reaction (PCR) inhibitors to be minimized because of the reduced elution time. Overall, this work added mechanistic insight into the extraction of DNA from DBS and developed a technique ideal for automation and point of care.
For decades, the article states, DBS have been used for the screening of newborns multiomics analysis (genomics, proteomics, and metabolomics) using LC-MS/MS. These techniques can provide reliable diagnostic source material to access patient samples from remote locations in Nepal and Bangladesh without having practiced phlebotomists and advanced technologies involved, due to analytes collected in the DBS papers being relatively stable and DBS papers being simple to move. However, although DBS has a role as a minimally invasive sample source, limitations exist regarding the possibility of widely using it for bioanalytical assays; reasons for this include sample preparation, and extraction efficiency. Although a variety of sample preparation methods are available to analysts (including solid-phase extraction, liquid-liquid extraction, andcombination reactions), it is difficult to perform steroid extraction from a DBS sample.
Although the analysis of steroids with LC-MS/MS for clinical application occurs often, it has become standard practice to perform method optimization and validation, as it is instrument specific, and there are lab-to-lab variabilities. The authors, therefore, chose a simple sample preparation process (protein precipitation), thus ensuring adaptability of automation utilized in the future. To eliminate the presence of any native steroids, the authors tested triplicates of blank whole blood, and observed consistently that there were no peaks at the expected retention times (RT) of the analytes. Because blood is a complicated matrix, they found it difficult to obtain uniform dispersion of T, 17-OHP, P, and C across a sample; thus, several iterations of the calibrators needed to be prepared and analyzed for reproducibility and consistency before analysts could begin other testing.
References
1. Fariha, R.; Rothkopf, E.; Murphy, J.; Walters, N.; Okoh, O. D.; Lawandy, N. M.; Tripathi, A. Electric Field-Assisted Dried Blood Spot Sample Preparation for Analysis of Steroids Using LC-MS/MS. Adv. Samp. Prep. 2024, 100115. DOI: 10.1016/j.sampre.2024.100115
2. Lee, K.; Murphy, J.; Tripathi, A. (2022). Electro-DBS: A Simple Method to Rapidly Extract Genomic DNA from Dried Blood Spots. Anal. Chem. 2022, 94. DOI: 10.1021/acs.analchem.2c02021
Characterization and Assessment of Effects of Drying Temperature on Edible Mushrooms with HS-GC–MS
September 6th 2024To gain insight into the effect of drying temperature on its composition, headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC–MS) was used for the identification of volatile organic compounds (VOCs) of 86 mushroom samples that were divided into five groups and dried at different temperatures.
Modern HPLC Strategies: Improving Retention and Peak Shape for Basic Analytes
August 16th 2024In high-performance liquid chromatography (HPLC), it is common for bases and unreacted ionized silanols on silica-based columns to cause irreproducible retention, broad peaks, and peak tailing when working with basic analytes. David S. Bell, Lead Consultant at ASKkPrime LLC offers innovative HPLC strategies that can help mitigate such issues.
Real-Time Measurement of EPA Regulated HON Compounds and Environmental Pollutants Using SIFT-MS
September 6th 2024This application note describes the determination of method detection limits (MDLs) for the newly regulated HON (Hazardous Organic NESHAP) compounds, which validate SIFT-MS as an effective solution for measuring these toxic VOCs and other environmental pollutants in ambient air, whether at the fence line or in a mobile setting.