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The aluminum alloys used in aerospace applications are susceptible to corrosion. This has led to the development of methodologies that ensure the durability of the parts and pieces of aircraft. These anticorrosive processes involve the use of coatings containing chromate-based corrosion-inhibitor compounds. Although these coatings provide an excellent solution to this problem, their use in protection protocols is restricted owing to their high toxicity and carcinogenic nature.This study evaluates a different process to protect aluminum alloy surfaces that incorporates the derivatization of organic compounds using potentiostatic techniques. The metallic surface was modified in situ by the potentiostatic reduction of aryl diazonium salts, leaving the surface covered with molecular grafts. The grafting of molecules onto the surface is modulated by the application of a potential that causes the formation of aryl radicals. The organic compound selected in this study was p-toluidine in protic medium. The derivatization process in the AA2060-T8 alloy was carried out at different pHs and potentials, observing from the potential/current responses in 0.1 M NaCl solution that the maximum optimization is obtained at pH 3 and -1 V.Likewise, the E/I and electrochemical impedance (EIS) responses of the electrografted samples modified and functionalized with cerium 4-hydroxycinnamate (Ce(4-OHcinn)3) revealed that the presence of this compound in the arylic structure significantly increased the protective capacity of the organic film electrografted on the aluminum alloy.The morphologies and characteristics of the modified surface were studied by SEM, TEM, and XPS. Furthermore, TEM examinations of ultramicrotomed sections of the electrografted specimens revealed the presence of a film approximately 10 nm thick on the AA2060-T8 surface.

Furfural compounds, including 5-hydroxymethylfurfural, furfural, and 5-methylfurfural, are common in foods and pose health risks. This study presents a pipette-tip solid-phase extraction with in-situ derivatization (PT-KF-SPE/ISD) method for rapid analysis of furfural compounds in various food matrices. Utilizing natural kapok fiber as an efficient adsorbent, this method integrates extraction and derivatization into a single step via a simple pull-push operation. Derivatization with 2,4-dinitrophenylhydrazine increases the hydrophobicity and ultraviolet absorption of furfural compounds, enabling sensitive liquid chromatography-ultraviolet detection. The method shows good linearity, sensitivity, and reproducibility, with limits of detection in ranges of 3.9–6.0 ng/mL. Real sample analysis confirms its applicability in detecting furfural compounds in beverages and herbal products, offering a reliable and eco-friendly solution for food safety and quality control. Five greenness assessment metrics demonstrate the method's excellent environmental friendliness. This approach highlights the advantages of combining natural adsorbents with in-situ derivatization for efficient food analysis.

Furfural compounds, including 5-hydroxymethylfurfural, furfural, and 5-methylfurfural, are common in foods and pose health risks. This study presents a pipette-tip solid-phase extraction with in-situ derivatization (PT-KF-SPE/ISD) method for rapid analysis of furfural compounds in various food matrices. Utilizing natural kapok fiber as an efficient adsorbent, this method integrates extraction and derivatization into a single step via a simple pull-push operation. Derivatization with 2,4-dinitrophenylhydrazine increases the hydrophobicity and ultraviolet absorption of furfural compounds, enabling sensitive liquid chromatography-ultraviolet detection. The method shows good linearity, sensitivity, and reproducibility, with limits of detection in ranges of 3.9-6.0 ng/mL. Real sample analysis confirms its applicability in detecting furfural compounds in beverages and herbal products, offering a reliable and eco-friendly solution for food safety and quality control. Five greenness assessment metrics demonstrate the method's excellent environmental friendliness. This approach highlights the advantages of combining natural adsorbents with in-situ derivatization for efficient food analysis., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)

[Display omitted] • Mini-KF-SLE-ISD was developed for aldehyde sample preparation in edible oil. • Simultaneous derivatization and extraction of aldehydes in edible oils were achieved. • Box-Behnken design optimization resulted in enhanced detection sensitivity. • The method proved simple, cost-effective, highly sensitive, and easy to automate. • Aldehyde changes during heating exhibited distinctions among various oil types. Heating edible oils generates aldehydes, potentially leading to adverse health effects, making their analysis essential for quality control. This study presents a convenient miniaturized kapok fiber-supported liquid-phase extraction/ in-situ derivatization method for the simultaneous extraction and derivatization of aldehydes in oils. The method involves placing 150 mg oil into a 1 mL pipette tip packed with 25 mg kapok fiber, adding 150 μL ACN with 1.5 mg mL−1 DNPH, and post 30-minute static extraction, retrieving the extractant with a pipettor for liquid chromatography-tandem mass spectrometry analysis. By optimizing critical parameters through a Box-Behnken design, the method exhibits good linearity (1–500 ng g−1, R2 ≥ 0.991), low detection limits (0.2–1.0 ng g−1), excellent accuracy (95.3–107.1%) and high precisions (relative standard deviation < 7.9%). This method simplifies sample preparation processes, cuts solvent use, and facilitates automation. It effectively identifies ten aldehyde variations in six heated oils, displaying distinct profiles consistent with prior research. [ABSTRACT FROM AUTHOR]

Catecholamines such as dopamine, norepinephrine and epinephrine are important neurotransmitters containing cis-diol moieties, and HPLC with fluorescence detection (HPLC-FD) has been successfully used as highly sensitive detection method for them. However, the complex matrix of biological samples is always a challenge. Boronate affinity microextraction is practical to purify and enrich cis-diol compounds. In this study, we used in-situ derivatization in boronate affinity polymer monolith microextraction (BA/PMME) to combine sample pretreatment and derivatization, then followed by HPLC-FD to develop a highly sensitive and selective determination method for catecholamines. Taking poly(3-acrylamidophenyl boronic acid-co-ethylene dimethacrylate) as BA/PMME material and TMBB-Su as labeling reagent, catecholamines could be derivatizated in polymer monolith in-situ together with the sample enrichment and purification. Comparing with commonly used solid phase extraction followed by derivatization, fewer operation steps are required and higher sensitivity was obtained with LODs as low as 0.06-0.2 nM. [ABSTRACT FROM AUTHOR]

• MSPE was used for the quick extraction and enrichment of trace levels of free androgens in female serum. • In situ derivatization on the surface of the MSPE adsorbent was performed to enhance the sensitivity. • A set of integration strategies were used to decrease nonspecific binding during ultrafiltration. • The method was used to evaluate the free testosterone and free androstendione levels in patients. Circulating free androgens are important indicators for a variety of diseases, so accurate determination of these hormones in serum is of great clinical significance. However, there are still many challenges for the accurate quantification of free androgens using mass methods because of their very low levels and complex interferences in serum, as well as the high serum protein binding rate and high nonspecific binding (NSB) rate. Here, an HPLC–MS/MS method coupled with magnetic solid phase extraction (MSPE) and in-situ derivatization was developed to quantify two free androgens—free testosterone (FT) and free androstenedione (FA 4)—in human serum simultaneously and accurately. Ultrafiltration was used to obtain free androgens in serum. To minimize the NSB rate and obtain accurate results, the ultrafiltration membrane was doubly modified with surfactant followed by a silane-coupling agent. Multiple pre-saturation with the tested samples was also used. With these strategies, the ultrafiltration recoveries were up to 95.4% for FT and 94.0% for FA 4 , so the NSB was negligible. After that, the extremely low levels of free androgens in ultrafiltrates were extracted and enriched using MSPE with core–shell structured ferroferric oxide coated with graphene oxide. Hydroxylamine hydrochloride was used to derivatize the analytes and the reaction took place on the surface of the adsorbent. All the extraction and derivatization conditions were optimized. Under such conditions, the assays were linear for FT within the range of 2–100 pg mL−1 and for FA 4 within the range of 5–500 pg mL−1. The intra- and inter-run CV was less than 12.3% and 10.9% for FT and less than 7.2% and 8.3% for FA 4 , respectively. For the intra- and inter-run accuracies, the relative error of the mean was 9.9% and 8.4% for FT, and 11.5% and 7.3% for FA 4 , respectively. The total extraction recoveries with MSPE in-situ derivatization were 93.2% for FT, 93.8% for FA 4 and 95.7% for the internal standard. The method was validated and was used to quantify the trace level of these two free androgens in serum samples from female patients suspected of having polycystic ovary syndrome (PCOS) accurately. It is expected to improve the diagnosis accuracy of PCOS when combined with other clinical indicators. [ABSTRACT FROM AUTHOR]

A rapid and solvent-free procedure for the determination of 4- tert-octylphenol and 4-nonylphenol isomers in aqueous samples is described. The method involves in-situ acetylation and microwave-assisted headspace solid-phase microextraction prior to their determination using gas chromatography-ion trap mass spectrometry operated in the selected ion storage mode. The dual experimental protocols to evaluate the effects of various derivatization and extraction parameters were investigated and the conditions optimized. Under optimized conditions, 300 μL of acetic anhydride mixed with 1 g of potassium hydrogencarbonate and 2 g of sodium chloride in a 20 mL aqueous sample were efficiently extracted by a 65 μm polydimethylsiloxane-divinylbenzene fiber that was located in the headspace when the system was microwave irradiated at 80 W for 5 min. The limits of quantitation were 5 and 50 ng/L for 4- tert-octylphenol and 4-nonylphenol isomers, respectively. The precision for these analytes, as indicated by relative standard deviations, were less than 8% for both intra- and inter-day analysis. Accuracy, expressed as the mean extraction recovery, was between 74 to 88%. A standard addition method was used to quantitate 4- tert-octylphenol and 4-nonylphenol isomers, and the concentrations ranged from 120 to 930 ng/L in various environmental water samples. [ABSTRACT FROM AUTHOR]

Abstract: Headspace solid phase microextraction (HS-SPME) in-situ supercritical fluid extraction (SFE) was investigated for the determination of trace amounts of perfluorocarboxylic acids (PFCAs) in sediments. Quantitation was performed by using gas chromatography coupled to negative chemical ionization–tandem mass spectrometry (GC–NCI–MS/MS). The optimum conditions of HS-SPME following SFE were obtained using 500μL n-butanol as a derivatization reagent in supercritical carbon dioxide with static extraction for 10min, then dynamic extraction for 20min at 30MPa and 70°C and simultaneous collected with 100μm film thickness PDMS fiber. The linear range of proposed method was from 5 to 5000ngg−1, with limit of detection ranging from 0.39 to 0.54ngg−1 and limit of quantitation ranging from 1.30 to 1.80ngg−1. The developed method was successfully applied to analyze PFCAs in sediments from rivers and beach near industrial areas. The concentrations of PFCAs determined are from 282 to 4473ngg−1. [Copyright &y& Elsevier]

Abstract: Stir bar sorptive extraction with in-situ derivatization using 2,3-diaminonaphthalene (DAN) followed by liquid desorption and high performance liquid chromatography with diode array detection (SBSE(DAN) in-situ -LD-HPLC-DAD) was developed for the determination of glyoxal (Gly) and methylglyoxal (MGly) in environmental and biological matrices. DAN proved very good specificity as in-situ derivatising agent for Gly and MGly in aqueous media, allowing the formation of adducts with remarkable sensitivity, selectivity and the absence of photodegradation. Assays performed on spiked (1.0μgL−1) water samples, under convenient experimental conditions, yielded recoveries of 96.2±7.9% for Gly and 96.1±6.4% for MGly. The analytical performance showed good accuracy, suitable precision (<12.0%), low detection limits (15ngL−1 for Gly and 25ngL−1 for MGly adducts) and excellent linear dynamic ranges (r 2 >0.99) from 0.1 to 120.0μgL−1. By using the standard addition method, the application of the present method to tap and swimming-pool water, beer, yeast cells suspension and urine samples allowed very good performance at the trace level. The proposed methodology proved to be a feasible alternative for routine quality control analysis, showing to be easy to implement, reliable, sensitive and with a low sample volume requirement to monitor Gly and MGly in environmental and biological matrices. [Copyright &y& Elsevier]

• A novel TiO 2 coated Fe 3 O 4 microsphere with core-shell structure was synthesized by a facile three-step route. • An integrated MSPE/in-situ derivatization procedure was performed in which analyte elution and derivatization can occur simultaneously to integrate two steps into one step. • The optimized method showed the shortest analysis time, highest sensitivity and lowest solvent consumption with a relatively satisfactory precision. In this study, for the first time, magnetic solid phase extraction (MSPE) was combined with in-situ derivatization to determine alendronate in plasma. TiO 2 coated Fe 3 O 4 microspheres (denoted as Fe 3 O 4 @TiO 2) were synthesized via polydopamine coating, titanium ions immobilizing and calcination steps. The as-prepared microspheres could selectively extract alendronate and be quickly isolated from plasma. The drug-adsorbed Fe 3 O 4 @TiO 2 microspheres were then directly incubated in derivatization reagent solution to perform novel in-situ derivatization and elution procedure, in which the derivatized alendronate lost its affinity to TiO 2 and was spontaneously eluted for further LC-MS/MS detection. Satisfactory results were obtained on the creative attempt to couple dispersive magnetic solid phase extraction with in-situ derivatization. The developed method was validated and demonstrated good linearity (0.05-500 ng mL−1), low detection limit (20 pg mL−1), great accuracy (100.6% to 105.3%) and precision (RSDs<5.27%). Manual operation and analysis time could be greatly reduced compared to other reported methods. The method was successfully applied to a pharmacokinetic study in beagle dogs. [ABSTRACT FROM AUTHOR]

Halloysite nanotubes loaded with 4-aminothiophenol capped silver nanoparticles (mHNTs-AgNPs4−ATP) composite was synthesized as a sensitive surface-enhanced Raman scattering (SERS) probe for the determination of nitrite ions in sausage and pork luncheon meat. The as-prepared composite was characterized by transmission electron microscope, X-ray diffraction spectroscopy and Fourier transform infrared spectroscopy. The as-synthesized mHNTs-AgNPs4−ATP composite with evenly distribution of AgNPs can provide in-situ derivatization site for sensitive and selective SERS detection of nitrite ions. Under acid condition, the 4-ATP capped on the AgNPs can be transformed into p , p '-dimercaptoazobenzene (DMAB) through nitrite-triggered diazo reaction. This efficient nitrite-triggered reaction can be used to detect nitrite via the characteristic peaks of DMAB at 1143 cm−1, 1392 cm−1, and 1434 cm−1. This SERS method has a wide logarithmic range of 0.0069–6.9 mg L−1, with detection limit of 0.78, 3.4, 0.51 μg L−1 at the peak of 1143 cm−1, 1392 cm−1, and 1434 cm−1, respectively. Besides, this method can be applied to detect nitrite ions in sausage and pork luncheon meat with relative standard deviation less than 10.3%, and the results were consistent with that analyzed by UV–Vis method. This method has good potential in efficient detection of meat product in food safety. Image 1 • A novel mHNTs-AgNPs4−ATP SERS probe was designed and prepared. • An in-situ derivatization SERS method was developed for selective detection of nitrite ions. • The SERS method was successfully applied to the analysis of sausage and pork luncheon meat. • The novel SERS method has the potential for rapid determination of complex meat products. [ABSTRACT FROM AUTHOR]

• An automatic online system was constructed for analysis of endogenous BRs. • A boronic reagent was immobilized on a polymer monolith for extraction and in-situ derivatization of BR. • Endogenous BRs in plant tissues less than 1.0 mg (FW) were quantified by the automatic system. An automatic and sensitive method which integrated polymer monolith microextraction and in-situ derivatization with liquid chromatography-mass spectrometry (PMME-ISD-LC-MS) was proposed for the quantification of endogenous brassinosteroids (BRs) in plant samples. In the described method, the anionic HIILIC monolithic column was modified with 2-methyl-4-phenylaminomethylphenylboronic acid (2-methyl-4-PAMBA) through ion exchange interaction and then used as a boronate affinity media to selectively capture, purify and derivatize BRs in crude extract through the reaction of the boronic acid group of 2-methyl-4-PAMBA and cis -diol on BRs. The BR derivatives were easily eluted by destroying the ion exchange interactions using the acidic eluting solvent, and then analyzed by LC-MS. The whole extraction and LC-MS analysis processes were automatically controlled which could be completed within 50 min. Under the optimized conditions, good linearities were obtained for six BRs with the correlation coefficients (R) ranging from 0.9953 to 0.9998. The limits of detection (LODs, S/N = 3) ranged from 0.10 to 1.29 pg mL−1. The recoveries were between 82.3% and 119.1% with the relative standard deviations (RSDs) ranging from 2.2% to 18.3%. Finally, the proposed method was applied for the quantification of endogenous BRs in various plant samples including different Oryza sativa L. cv. tissues (1.0 mg, fresh weight (FW)), Phaseolus vulgaris L. (1.0 mg FW), Vigna unguiculata (1.0 mg FW), Arabidopsis thaliana flower (1.3 mg FW). [ABSTRACT FROM AUTHOR]

In this study, magnetic solid phase extraction coupled with in-situ derivatization (MSPE-ISD) was established for the determination of hexanal and heptanal in human urine. 2,4-Dinitrophenylhydrazine (DNPH) was used as the derivatization reagent that was adsorbed onto the surface of magnetite/silica/poly(methacrylic acid-co-ethylene glycol dimethacrylate) (Fe3O4/SiO2/P(MAA-co-EGDMA)). And then simultaneous extraction and derivatization of the aldehydes were performed on the DNPH-adsorbed Fe3O4/SiO2/P(MAA-co-EGDMA). The simple, rapid and sensitive determination of hexanal and heptanal can be accomplished within 9min. Under optimized conditions, the limits of detection (LODs) were 1.7 and 2.5nmol/L for hexanal and heptanal, respectively. The relative recoveries ranged from 72.8% to 91.4% with the intra- and inter-day relative standard deviations (RSDs) being less than 9.6%. Furthermore, the proposed method was successfully applied to determine endogenous hexanal and heptanal in human urine from healthy persons and lung cancer patients. The results showed the higher concentrations of hexanal and heptanal were observed in lung cancer patients compared to healthy controls. Thus, the developed MSPE-ISD method is suitable for the determination of aldehydes in urines., (Copyright © 2015 Elsevier B.V. All rights reserved.)