TY  - JOUR
AU  - Walther, Rasmus
AU  - Krmar, Jovana
AU  - Leistner, Adrian
AU  - Svrkota, Bojana
AU  - Otašević, Biljana
AU  - Malenović, Anđelija
AU  - Holzgrabe, Ulrike
AU  - Protić, Ana
PY  - 2023
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/4698
AB  - An alternative to the time-consuming and error-prone pharmacopoeial gas chromatography method for the analysis of fatty acids (FAs) is urgently needed. The objective was therefore to propose a robust liquid chromatography method with charged aerosol detection for the analysis of polysorbate 80 (PS80) and magnesium stearate. FAs with different numbers of carbon atoms in the chain necessitated the use of a gradient method with a Hypersil Gold C18 column and acetonitrile as organic modifier. The risk-based Analytical Quality by Design approach was applied to define the Method Operable Design Region (MODR). Formic acid concentration, initial and final percentages of acetonitrile, gradient elution time, column temperature, and mobile phase flow rate were identified as critical method parameters (CMPs). The initial and final percentages of acetonitrile were fixed while the remaining CMPs were fine-tuned using response surface methodology. Critical method attributes included the baseline separation of adjacent peaks (α-linolenic and myristic acid, and oleic and petroselinic acid) and the retention factor of the last compound eluted, stearic acid. The MODR was calculated by Monte Carlo simulations with a probability equal or greater than 90%. Finally, the column temperature was set at 33 °C, the flow rate was 0.575 mL/min, and acetonitrile linearly increased from 70 to 80% (v/v) within 14.2 min.
PB  - MDPI
T2  - Pharmaceuticals
T1  - Analytical Quality by Design: Achieving Robustness of an LC-CAD Method for the Analysis of Non-Volatile Fatty Acids
VL  - 16
IS  - 4
DO  - 10.3390/ph16040478
ER  - 

@article{
author = "Walther, Rasmus and Krmar, Jovana and Leistner, Adrian and Svrkota, Bojana and Otašević, Biljana and Malenović, Anđelija and Holzgrabe, Ulrike and Protić, Ana",
year = "2023",
abstract = "An alternative to the time-consuming and error-prone pharmacopoeial gas chromatography method for the analysis of fatty acids (FAs) is urgently needed. The objective was therefore to propose a robust liquid chromatography method with charged aerosol detection for the analysis of polysorbate 80 (PS80) and magnesium stearate. FAs with different numbers of carbon atoms in the chain necessitated the use of a gradient method with a Hypersil Gold C18 column and acetonitrile as organic modifier. The risk-based Analytical Quality by Design approach was applied to define the Method Operable Design Region (MODR). Formic acid concentration, initial and final percentages of acetonitrile, gradient elution time, column temperature, and mobile phase flow rate were identified as critical method parameters (CMPs). The initial and final percentages of acetonitrile were fixed while the remaining CMPs were fine-tuned using response surface methodology. Critical method attributes included the baseline separation of adjacent peaks (α-linolenic and myristic acid, and oleic and petroselinic acid) and the retention factor of the last compound eluted, stearic acid. The MODR was calculated by Monte Carlo simulations with a probability equal or greater than 90%. Finally, the column temperature was set at 33 °C, the flow rate was 0.575 mL/min, and acetonitrile linearly increased from 70 to 80% (v/v) within 14.2 min.",
publisher = "MDPI",
journal = "Pharmaceuticals",
title = "Analytical Quality by Design: Achieving Robustness of an LC-CAD Method for the Analysis of Non-Volatile Fatty Acids",
volume = "16",
number = "4",
doi = "10.3390/ph16040478"
}

Walther, R., Krmar, J., Leistner, A., Svrkota, B., Otašević, B., Malenović, A., Holzgrabe, U.,& Protić, A.. (2023). Analytical Quality by Design: Achieving Robustness of an LC-CAD Method for the Analysis of Non-Volatile Fatty Acids. in Pharmaceuticals
MDPI., 16(4).
https://doi.org/10.3390/ph16040478

Walther R, Krmar J, Leistner A, Svrkota B, Otašević B, Malenović A, Holzgrabe U, Protić A. Analytical Quality by Design: Achieving Robustness of an LC-CAD Method for the Analysis of Non-Volatile Fatty Acids. in Pharmaceuticals. 2023;16(4).
doi:10.3390/ph16040478 .

Walther, Rasmus, Krmar, Jovana, Leistner, Adrian, Svrkota, Bojana, Otašević, Biljana, Malenović, Anđelija, Holzgrabe, Ulrike, Protić, Ana, "Analytical Quality by Design: Achieving Robustness of an LC-CAD Method for the Analysis of Non-Volatile Fatty Acids" in Pharmaceuticals, 16, no. 4 (2023),
https://doi.org/10.3390/ph16040478 . .

TY  - JOUR
AU  - Đajić, Nevena
AU  - Petković, Miloš
AU  - Zečević, Mira
AU  - Otašević, Biljana
AU  - Malenović, Anđelija
AU  - Holzgrabe, Ulrike
AU  - Protić, Ana
PY  - 2021
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/3822
AB  - The quantitative structure-retention relationship (QSRR) models are not only employed in retention behaviour prediction, but also in an in-depth understanding of complex chromatographic systems. The goal of the present research is to enable the comprehensive understanding of retention underlying the separation in β-cyclodextrin (CD) modified reversed-phase high performance liquid chromatography (RP-HPLC) systems, through the development of mixed QSRR models. Moreover, the amount of β-CD adsorbed on the stationary phase surface (β-CDA) is added as the model's input in order to evaluate its contribution to both model performances and retention. Nuclear magnetic resonance (NMR) experiments were conducted to confirm the predicted inclusion complex structures and support the application of in silico tools. The most significant descriptors revealed that retention is governed by the steric factors 7.5 Å distant from the geometrical centre of a molecule, 3D arrangement of atoms determining the molecular size and shape, lipophilicity indicated by topological distances, as well as the unbound system's energy, related to the inclusion complex formation. In addition, a notable effect of the pH of the aqueous phase on the retention of ionizable analytes was shown. In the case of pH of the aqueous phase and β-CDA the change in retention behaviour of the studied analytes was observed only at the highest β-CDA value (5.17 μM/m2), but it was not related to the ionization state of analytes. When the analytes did not change the ionization form across the investigated studied pH range, and the acetonitrile content in the mobile phase was 25% (v/v), the retention factor had low values regardless of the β-CDA; under these circumstances the retention is probably acetonitrile driven.
PB  - Elsevier B.V.
T2  - Journal of Chromatography A
T1  - A comprehensive study on retention of selected model substances in β-cyclodextrin-modified high performance liquid chromatography
VL  - 1645
DO  - 10.1016/j.chroma.2021.462120
ER  - 

@article{
author = "Đajić, Nevena and Petković, Miloš and Zečević, Mira and Otašević, Biljana and Malenović, Anđelija and Holzgrabe, Ulrike and Protić, Ana",
year = "2021",
abstract = "The quantitative structure-retention relationship (QSRR) models are not only employed in retention behaviour prediction, but also in an in-depth understanding of complex chromatographic systems. The goal of the present research is to enable the comprehensive understanding of retention underlying the separation in β-cyclodextrin (CD) modified reversed-phase high performance liquid chromatography (RP-HPLC) systems, through the development of mixed QSRR models. Moreover, the amount of β-CD adsorbed on the stationary phase surface (β-CDA) is added as the model's input in order to evaluate its contribution to both model performances and retention. Nuclear magnetic resonance (NMR) experiments were conducted to confirm the predicted inclusion complex structures and support the application of in silico tools. The most significant descriptors revealed that retention is governed by the steric factors 7.5 Å distant from the geometrical centre of a molecule, 3D arrangement of atoms determining the molecular size and shape, lipophilicity indicated by topological distances, as well as the unbound system's energy, related to the inclusion complex formation. In addition, a notable effect of the pH of the aqueous phase on the retention of ionizable analytes was shown. In the case of pH of the aqueous phase and β-CDA the change in retention behaviour of the studied analytes was observed only at the highest β-CDA value (5.17 μM/m2), but it was not related to the ionization state of analytes. When the analytes did not change the ionization form across the investigated studied pH range, and the acetonitrile content in the mobile phase was 25% (v/v), the retention factor had low values regardless of the β-CDA; under these circumstances the retention is probably acetonitrile driven.",
publisher = "Elsevier B.V.",
journal = "Journal of Chromatography A",
title = "A comprehensive study on retention of selected model substances in β-cyclodextrin-modified high performance liquid chromatography",
volume = "1645",
doi = "10.1016/j.chroma.2021.462120"
}

Đajić, N., Petković, M., Zečević, M., Otašević, B., Malenović, A., Holzgrabe, U.,& Protić, A.. (2021). A comprehensive study on retention of selected model substances in β-cyclodextrin-modified high performance liquid chromatography. in Journal of Chromatography A
Elsevier B.V.., 1645.
https://doi.org/10.1016/j.chroma.2021.462120

Đajić N, Petković M, Zečević M, Otašević B, Malenović A, Holzgrabe U, Protić A. A comprehensive study on retention of selected model substances in β-cyclodextrin-modified high performance liquid chromatography. in Journal of Chromatography A. 2021;1645.
doi:10.1016/j.chroma.2021.462120 .

Đajić, Nevena, Petković, Miloš, Zečević, Mira, Otašević, Biljana, Malenović, Anđelija, Holzgrabe, Ulrike, Protić, Ana, "A comprehensive study on retention of selected model substances in β-cyclodextrin-modified high performance liquid chromatography" in Journal of Chromatography A, 1645 (2021),
https://doi.org/10.1016/j.chroma.2021.462120 . .

TY  - JOUR
AU  - Pawellek, Ruben
AU  - Krmar, Jovana
AU  - Leistner, Adrian
AU  - Đajić, Nevena
AU  - Otašević, Biljana
AU  - Protić, Ana
AU  - Holzgrabe, Ulrike
PY  - 2021
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/3926
AB  - The charged aerosol detector (CAD) is the latest representative of aerosol-based detectors that generate a response  independent of the analytes’ chemical structure. This study was aimed at accurately predicting the CAD response  of homologous fatty acids under varying experimental conditions. Fatty acids from C12 to C18 were used as model  substances due to semivolatile characterics that caused non-uniform CAD behaviour. Considering both experimental  conditions and molecular descriptors, a mixed quantitative structure–property relationship (QSPR) modeling was  performed using Gradient Boosted Trees (GBT ). The ensemble of 10 decisions trees (learning rate set at 0.55, the  maximal depth set at 5, and the sample rate set at 1.0) was able to explain approximately 99%  (Q2: 0.987, RMSE: 0.051)  of the observed variance in CAD responses. Validation using an external test compound confirmed the high predic- tive ability of the model established  (R2: 0.990, RMSEP: 0.050). With respect to the intrinsic attribute selection strategy,  GBT used almost all independent variables during model building. Finally, it attributed the highest importance to  the power function value, the flow rate of the mobile phase, evaporation temperature, the content of the organic  solvent in the mobile phase and the molecular descriptors such as molecular weight (MW ), Radial Distribution Func- tion—080/weighted by mass (RDF080m) and average coefficient of the last eigenvector from distance/detour matrix  (Ve2_D/Dt). The identification of the factors most relevant to the CAD responsiveness has contributed to a better  understanding of the underlying mechanisms of signal generation. An increased CAD response that was obtained for  acetone as organic modifier demonstrated its potential to replace the more expensive and environmentally harmful  acetonitrile.
PB  - BioMed Central Ltd
T2  - Journal of Cheminformatics
T1  - Charged aerosol detector response modeling for fatty acids based on experimental settings and molecular features: a machine learning approach
VL  - 13
IS  - 1
DO  - 10.1186/s13321-021-00532-0
ER  - 

@article{
author = "Pawellek, Ruben and Krmar, Jovana and Leistner, Adrian and Đajić, Nevena and Otašević, Biljana and Protić, Ana and Holzgrabe, Ulrike",
year = "2021",
abstract = "The charged aerosol detector (CAD) is the latest representative of aerosol-based detectors that generate a response  independent of the analytes’ chemical structure. This study was aimed at accurately predicting the CAD response  of homologous fatty acids under varying experimental conditions. Fatty acids from C12 to C18 were used as model  substances due to semivolatile characterics that caused non-uniform CAD behaviour. Considering both experimental  conditions and molecular descriptors, a mixed quantitative structure–property relationship (QSPR) modeling was  performed using Gradient Boosted Trees (GBT ). The ensemble of 10 decisions trees (learning rate set at 0.55, the  maximal depth set at 5, and the sample rate set at 1.0) was able to explain approximately 99%  (Q2: 0.987, RMSE: 0.051)  of the observed variance in CAD responses. Validation using an external test compound confirmed the high predic- tive ability of the model established  (R2: 0.990, RMSEP: 0.050). With respect to the intrinsic attribute selection strategy,  GBT used almost all independent variables during model building. Finally, it attributed the highest importance to  the power function value, the flow rate of the mobile phase, evaporation temperature, the content of the organic  solvent in the mobile phase and the molecular descriptors such as molecular weight (MW ), Radial Distribution Func- tion—080/weighted by mass (RDF080m) and average coefficient of the last eigenvector from distance/detour matrix  (Ve2_D/Dt). The identification of the factors most relevant to the CAD responsiveness has contributed to a better  understanding of the underlying mechanisms of signal generation. An increased CAD response that was obtained for  acetone as organic modifier demonstrated its potential to replace the more expensive and environmentally harmful  acetonitrile.",
publisher = "BioMed Central Ltd",
journal = "Journal of Cheminformatics",
title = "Charged aerosol detector response modeling for fatty acids based on experimental settings and molecular features: a machine learning approach",
volume = "13",
number = "1",
doi = "10.1186/s13321-021-00532-0"
}

Pawellek, R., Krmar, J., Leistner, A., Đajić, N., Otašević, B., Protić, A.,& Holzgrabe, U.. (2021). Charged aerosol detector response modeling for fatty acids based on experimental settings and molecular features: a machine learning approach. in Journal of Cheminformatics
BioMed Central Ltd., 13(1).
https://doi.org/10.1186/s13321-021-00532-0

Pawellek R, Krmar J, Leistner A, Đajić N, Otašević B, Protić A, Holzgrabe U. Charged aerosol detector response modeling for fatty acids based on experimental settings and molecular features: a machine learning approach. in Journal of Cheminformatics. 2021;13(1).
doi:10.1186/s13321-021-00532-0 .

Pawellek, Ruben, Krmar, Jovana, Leistner, Adrian, Đajić, Nevena, Otašević, Biljana, Protić, Ana, Holzgrabe, Ulrike, "Charged aerosol detector response modeling for fatty acids based on experimental settings and molecular features: a machine learning approach" in Journal of Cheminformatics, 13, no. 1 (2021),
https://doi.org/10.1186/s13321-021-00532-0 . .

TY  - JOUR
AU  - Đajić, Nevena
AU  - Otašević, Biljana
AU  - Malenović, Anđelija
AU  - Zečević, Mira
AU  - Holzgrabe, Ulrike
AU  - Protić, Ana
PY  - 2021
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/3728
AB  - Binding between cyclodextrin (CD) cavity and guest molecule in Reversed Phase High-Performance Liquid Chromatography (RP-HPLC) is dynamic process. In general, increasing CD concentration is inducing inclusion complex formation, leading to reduction of analyte's retention time. Consequently, the shortness in retention time is a measure of complex stability in HPLC. However, under certain experimental conditions, the retention of some analytes could be prolonged even when concentration of CD in the mobile phase is increased. In order to reveal the cause of this unexpected retention behavior, the present study was carried on. The model mixture consisted of risperidone, olanzapine and their related impurities, while β-CD was selected among CDs, as in the previous study. In order to achieve fast equilibrium between free analyte and β-CD-analyte complex, β-CD was not added to the mobile phase, but only to the sample. Detection was performed with Corona Charged Aerosol Detector (CAD), suitable for non-chromophoric β-CD. When analyzing olanzapine impurity B-β-CD sample, three peaks were detected, namely free β-CD, β-CD-analyte complex and free analyte. The complex stability constant was calculated employing a modification of the Benesi-Hildebrandt equation and CAD has proven to be useful in complex stability constants assessment if retention of free analyte and β-CD-analyte complex is distinguished. For all other analytes only two peaks could be detected, because free analyte and formed complex are eluting at the same retention time. Under such circumstances, the authors proposed the methodology for calculating stability constants and confirmed its applicability to studied model mixture.
PB  - Elsevier B.V.
T2  - Journal of Pharmaceutical and Biomedical Analysis
T1  - Corona Charged Aerosol Detector in studying retention and β-cyclodextrin complex stability using RP-HPLC
VL  - 193
DO  - 10.1016/j.jpba.2020.113711
ER  - 

@article{
author = "Đajić, Nevena and Otašević, Biljana and Malenović, Anđelija and Zečević, Mira and Holzgrabe, Ulrike and Protić, Ana",
year = "2021",
abstract = "Binding between cyclodextrin (CD) cavity and guest molecule in Reversed Phase High-Performance Liquid Chromatography (RP-HPLC) is dynamic process. In general, increasing CD concentration is inducing inclusion complex formation, leading to reduction of analyte's retention time. Consequently, the shortness in retention time is a measure of complex stability in HPLC. However, under certain experimental conditions, the retention of some analytes could be prolonged even when concentration of CD in the mobile phase is increased. In order to reveal the cause of this unexpected retention behavior, the present study was carried on. The model mixture consisted of risperidone, olanzapine and their related impurities, while β-CD was selected among CDs, as in the previous study. In order to achieve fast equilibrium between free analyte and β-CD-analyte complex, β-CD was not added to the mobile phase, but only to the sample. Detection was performed with Corona Charged Aerosol Detector (CAD), suitable for non-chromophoric β-CD. When analyzing olanzapine impurity B-β-CD sample, three peaks were detected, namely free β-CD, β-CD-analyte complex and free analyte. The complex stability constant was calculated employing a modification of the Benesi-Hildebrandt equation and CAD has proven to be useful in complex stability constants assessment if retention of free analyte and β-CD-analyte complex is distinguished. For all other analytes only two peaks could be detected, because free analyte and formed complex are eluting at the same retention time. Under such circumstances, the authors proposed the methodology for calculating stability constants and confirmed its applicability to studied model mixture.",
publisher = "Elsevier B.V.",
journal = "Journal of Pharmaceutical and Biomedical Analysis",
title = "Corona Charged Aerosol Detector in studying retention and β-cyclodextrin complex stability using RP-HPLC",
volume = "193",
doi = "10.1016/j.jpba.2020.113711"
}

Đajić, N., Otašević, B., Malenović, A., Zečević, M., Holzgrabe, U.,& Protić, A.. (2021). Corona Charged Aerosol Detector in studying retention and β-cyclodextrin complex stability using RP-HPLC. in Journal of Pharmaceutical and Biomedical Analysis
Elsevier B.V.., 193.
https://doi.org/10.1016/j.jpba.2020.113711

Đajić N, Otašević B, Malenović A, Zečević M, Holzgrabe U, Protić A. Corona Charged Aerosol Detector in studying retention and β-cyclodextrin complex stability using RP-HPLC. in Journal of Pharmaceutical and Biomedical Analysis. 2021;193.
doi:10.1016/j.jpba.2020.113711 .

Đajić, Nevena, Otašević, Biljana, Malenović, Anđelija, Zečević, Mira, Holzgrabe, Ulrike, Protić, Ana, "Corona Charged Aerosol Detector in studying retention and β-cyclodextrin complex stability using RP-HPLC" in Journal of Pharmaceutical and Biomedical Analysis, 193 (2021),
https://doi.org/10.1016/j.jpba.2020.113711 . .

TY  - JOUR
AU  - Schilling, Klaus
AU  - Krmar, Jovana
AU  - Maljurić, Nevena
AU  - Pawellek, Ruben
AU  - Protić, Ana
AU  - Holzgrabe, Ulrike
PY  - 2019
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/3337
AB  - In this study, a quantitative structure-property relationship model was built in order to link molecular descriptors and chromatographic parameters as inputs towards CAD responsiveness. Aminoglycoside antibiotics, sugars, and acetylated amino sugars, which all lack a UV/vis chromophore, were selected as model substances due to their polar nature that represents a challenge in generating a CAD response. Acetone, PFPA, flow rate, data rate, filter constant, SM5_B(s), ATS7s, SpMin1_Bh(v), Mor09e, Mor22e, E1u, R7v+, and VP as the most influential inputs were correlated with the CAD response by virtue of ANN applying a backpropagation learning rule. External validation on previously unseen substances showed that the developed 13-6-3-1 ANN model could be used for CAD response prediction across the examined experimental domain reliably (R-2 0.989 and RMSE 0.036). The obtained network was used to reveal CAD response correlations. The impact of organic modifier content and flow rate was in accordance with the theory of the detector's functioning. Additionally, the significance of SpMin1_Bh(v) aided in emphasizing the often neglected surface-dependent CAD character, while the importance of Mor22e as a molecular descriptor accentuated its dependency on the number of electronegative atoms taking part in charging the formed particles. The significance of PFPA demonstrated the possibility of using evaporative chaotropic reagents in CAD response improvement when dealing with highly polar substances that act as kosmotropes. The network was also used in identifying possible interactions between the most significant inputs. A joint effect of PFPA and acetone was shown, representing a good starting point for further investigation with different and, especially, eco-friendly organic solvents and chaotropic agents in the routine application of CAD.
PB  - Springer Heidelberg, Heidelberg
T2  - Analytical and Bioanalytical Chemistry
T1  - Quantitative structure-property relationship modeling of polar analytes lacking UV chromophores to charged aerosol detector response
VL  - 411
IS  - 13
SP  - 2945
EP  - 2959
DO  - 10.1007/s00216-019-01744-y
ER  - 

@article{
author = "Schilling, Klaus and Krmar, Jovana and Maljurić, Nevena and Pawellek, Ruben and Protić, Ana and Holzgrabe, Ulrike",
year = "2019",
abstract = "In this study, a quantitative structure-property relationship model was built in order to link molecular descriptors and chromatographic parameters as inputs towards CAD responsiveness. Aminoglycoside antibiotics, sugars, and acetylated amino sugars, which all lack a UV/vis chromophore, were selected as model substances due to their polar nature that represents a challenge in generating a CAD response. Acetone, PFPA, flow rate, data rate, filter constant, SM5_B(s), ATS7s, SpMin1_Bh(v), Mor09e, Mor22e, E1u, R7v+, and VP as the most influential inputs were correlated with the CAD response by virtue of ANN applying a backpropagation learning rule. External validation on previously unseen substances showed that the developed 13-6-3-1 ANN model could be used for CAD response prediction across the examined experimental domain reliably (R-2 0.989 and RMSE 0.036). The obtained network was used to reveal CAD response correlations. The impact of organic modifier content and flow rate was in accordance with the theory of the detector's functioning. Additionally, the significance of SpMin1_Bh(v) aided in emphasizing the often neglected surface-dependent CAD character, while the importance of Mor22e as a molecular descriptor accentuated its dependency on the number of electronegative atoms taking part in charging the formed particles. The significance of PFPA demonstrated the possibility of using evaporative chaotropic reagents in CAD response improvement when dealing with highly polar substances that act as kosmotropes. The network was also used in identifying possible interactions between the most significant inputs. A joint effect of PFPA and acetone was shown, representing a good starting point for further investigation with different and, especially, eco-friendly organic solvents and chaotropic agents in the routine application of CAD.",
publisher = "Springer Heidelberg, Heidelberg",
journal = "Analytical and Bioanalytical Chemistry",
title = "Quantitative structure-property relationship modeling of polar analytes lacking UV chromophores to charged aerosol detector response",
volume = "411",
number = "13",
pages = "2945-2959",
doi = "10.1007/s00216-019-01744-y"
}

Schilling, K., Krmar, J., Maljurić, N., Pawellek, R., Protić, A.,& Holzgrabe, U.. (2019). Quantitative structure-property relationship modeling of polar analytes lacking UV chromophores to charged aerosol detector response. in Analytical and Bioanalytical Chemistry
Springer Heidelberg, Heidelberg., 411(13), 2945-2959.
https://doi.org/10.1007/s00216-019-01744-y

Schilling K, Krmar J, Maljurić N, Pawellek R, Protić A, Holzgrabe U. Quantitative structure-property relationship modeling of polar analytes lacking UV chromophores to charged aerosol detector response. in Analytical and Bioanalytical Chemistry. 2019;411(13):2945-2959.
doi:10.1007/s00216-019-01744-y .

Schilling, Klaus, Krmar, Jovana, Maljurić, Nevena, Pawellek, Ruben, Protić, Ana, Holzgrabe, Ulrike, "Quantitative structure-property relationship modeling of polar analytes lacking UV chromophores to charged aerosol detector response" in Analytical and Bioanalytical Chemistry, 411, no. 13 (2019):2945-2959,
https://doi.org/10.1007/s00216-019-01744-y . .