Development of a Biocompatible In-Tube Solid-Phase Microextraction Device: A Sensitive Approach for Direct Analysis of Single Drops of Complex Matrixes
Bibliographic record
Abstract
The aim of the current study is to develop a sensitive solid-phase microextraction (SPME) device for direct and rapid analysis of untreated complex matrixes (i.e., single drop of the samples, V ≤ 2 μL). A thin layer of a biocompatible nanostructured polypyrrole (PPy) was electrochemically deposited inside a medical grade spinal needle, minimizing the matrix effect. Microsampling was facilitated by loading the sample inside the in-tube SPME device (withdraw of sample via plunger), where extraction was performed under static conditions. Two strategies were used for analysis of the compounds including offline desorption and running the extract to the liquid chromatograph-tandem mass spectrometer (LC-MS/MS) or direct coupling of the in-tube SPME device to the MS. Given the high surface-area-to-volume ratio of the coating, a short equilibrium time (i.e., t ≤ 2 min) was obtained. The whole analytical procedure (i.e., extraction, rinsing, desorption, and LC-MS/MS analysis) was performed within 10 min by LC-MS/MS, and 3 min by in-tube-MS/MS. Possible matrix effects for the prepared device were evaluated in whole blood samples at three levels of concentration, and encouraging results were achieved in the range of 83-120%. The obtained results, no matrix effect, are attributed to the smooth surface and small pore size of the biocompatible PPy coating, which was prepared in the presence of cetyltrimethylammonium bromide (CTAB) surfactant. The in-tube SPME device was shown to be very sensitive, with high total recoveries obtained for all compounds in phosphate-buffered saline (PBS) and urine samples owing to the large volume and capacity of the coating. Subnanogram per milliliter levels of detection were achieved for urine samples, and low nanogram per milliliter levels were found in whole blood samples for all studied compounds with a high protein binding index. Rapid analysis of whole blood samples was achieved without need of any pretreatment or manipulation of sample, revealing the developed in-tube SPME device as an ideal probe for forensic application, drug monitoring, and point-of care-diagnosis.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".