Development and validation of an<i>in situ</i>and real-time quantification method for bicarbonate, carbonate and orthophosphate ions by ATR FT-IR spectroscopy in aqueous solutions
Bibliographic record
Abstract
Bicarbonate salts are used in various industrial processes and could even serve as an alternative source of carbon in bioprocesses involving photosynthetic organisms. Industrial productions require efficient monitoring and control to ensure that their output will meet target specifications. To this end, a simple and rapid in situ quantification method was developed for bicarbonate, carbonate and phosphate ions using Attenuated Total Reflectance-Fourier Transform Infrared (ATR FT-IR) spectroscopy combined with partial least squares (PLS). The resulting multivariate approach allows the simultaneous determination of inorganic carbon and orthophosphate ions concentrations in aqueous solutions (R2 > 0.98, root-mean-square-errors of the cross validation RMSECV < 3.3%). Validation of the method was achieved through replicability and repeatability tests. Univariate calibration graphs are linear over a concentration range of 150 mM (R2 > 0.9990). Quantification limits for those ions were in the 6.9-17.2 mM range, as determined from univariate models. The multivariate model was successfully applied to a microalgal culture of Scenedesmus obliquus using bicarbonate as the carbon source and a phosphate buffer to maintain the pH. This analytical technique did not require extraction or chemical treatment and no sample preparation is needed. The results demonstrate the potential of ATR FT-IR method to study inorganic carbon and phosphate species during a bioprocess.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 source (direct Gemma or distilled Codex), 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".