Hybrid materials based on deep eutectic solvents for the preconcentration of formaldehyde by SPME in coffee beverages

Coffee is one of the most widely consumed beverages. It can be prepared from green or roasted beans or from instant coffee. Unfortunately, in addition to the aroma obtained in the coffee roasting process, among others, formaldehyde can be produced. In this study, thin-film solid-phase microextraction was used to preconcentrate trace amounts of formaldehyde in different types of coffee with different roasting levels. For this purpose, 18 hybrid materials based on deep eutectic solvents were synthesized and tested as sorbents in thin-film solid-phase microextraction. The coffee samples were brewed, and then formaldehyde present in them was derivatized using the Nash reagent. The sample preparation procedure was optimized for selected DES-based sorbent using a central composite design method and validated. Formaldehyde was determined in almost all samples of second-crack coffee (roasted at 240 °C) at 0.17-0.75 ng mL-1 and in darker-colored instant coffees at 0.18-0.54 ng mL-1.

Deep Eutectic Solvent-Based Coating Sorbent for Preconcentration of Formaldehyde by Thin-Film Solid-Phase Microextraction Technique

A thin-film solid-phase microextraction method with a sorbent composed of a deep eutectic solvent was developed for the preconcentration of formaldehyde from river and lake water samples. Four new deep eutectic solvents (DESs) were synthesized, each in molar ratios 1:1, 1:2, and 1:3. Among prepared compounds, the greatest efficiency in the proposed method of preconcentration of formaldehyde derivatized with Nash reagent was demonstrated by DES-3 consisting of benzyldimethylhexadecylammonium chloride and lauric acid, in a molar ratio of 1:3. For the proposed method, the parameters affecting the extraction efficiency of formaldehyde were optimized (including the choice of DES-based sorbent and desorption solvent as well as the sample volume and pH, the salting-out effect, the extraction time, and the desorption time). Under optimal conditions, the proposed method achieved good precision between 3.3% (for single sorbent) and 4.8% (for sorbent-to-sorbent) as well as good recovery ranging from 78.0 to 99.1%. The limits of detection and quantitation were 0.15 ng mL−1 and 0.50 ng mL−1, respectively. The enrichment factor was equal to 178. The developed method was successfully applied to determine formaldehyde in environmental water samples.

A reversed phase HPLC-UV method for the simultaneous determination of residual formaldehyde and Triton X-100 in vaccine products

Many of the inactivated viral vaccines for human and animal use are manufactured using formaldehyde as an inactivating agent. Apart from formaldehyde, Triton X-100 is also one of the chemicals commonly used in viral vaccine manufacturing. Triton X-100 is typically used to extract the cell-associated viruses and / or components during manufacturing process. The concentration of formaldehyde and Triton X-100 in the final bulks are also reduced during vaccine purification process. Here we report a simple RP-HPLC-UV based method for the quantification of residual Triton X-100 and formaldehyde as process impurities in viral vaccines. This method is also adopted for the residual impurity determination of either formaldehyde or Triton X-100 in other non-viral vaccines, multivalent as well as sub-unit vaccines, such as liquid pentavalent, includes TT, DT, Hepatitis B (rDNA) and Haemophilus type b conjugate vaccine (adsorbed). This method is rapid and can quantify both Triton X-100 and formaldehyde in a single preparation with improved peak asymmetry. This new assay has a linearity range starting from 0.0625 to 1 µg/mL for formaldehyde and 0.625-10 µg/mL for Triton X-100. This method would be very useful for viral vaccine manufacturing and release.

A Robust Static Headspace GC-FID Method to Detect and Quantify Formaldehyde Impurity in Pharmaceutical Excipients

Formaldehyde is a highly reactive impurity that can be found in many pharmaceutical excipients. Trace levels of this impurity may affect drug product stability, safety, efficacy, and performance. A static headspace gas chromatographic method was developed and validated to determine formaldehyde in pharmaceutical excipients after an effective derivatization procedure using acidified ethanol. Diethoxymethane, the derivative of formaldehyde, was then directly analyzed by GC-FID. Despite the simplicity of the developed method, however, it is characterized by its specificity, accuracy, and precision. The limits of detection and quantification of formaldehyde in the samples were of 2.44 and 8.12 µg/g, respectively. This method is characterized by using simple and economic GC-FID technique instead of MS detection, and it is successfully used to analyze formaldehyde in commonly used pharmaceutical excipients.

Simple high-performance liquid chromatography method for formaldehyde determination in human tissue through derivatization with 2,4-dinitrophenylhydrazine

A simple high-performance liquid chromatography method has been developed for the determination of formaldehyde in human tissue. FA Formaldehyde was derivatized with 2,4-dinitrophenylhydrazine. It was extracted from human tissue with ethyl acetate by liquid-liquid extraction and analyzed by high-performance liquid chromatography. The calibration curve was linear in the concentration range of 5.0-200 μg/mL. Intra- and interday precision values for formaldehyde in tissue were <6.9%, and accuracy (relative error) was better than 6.5%. The extraction recoveries of formaldehyde from human tissue were between 88 and 98%. The limits of detection and quantification of formaldehyde were 1.5 and 5.0 μg/mL, respectively. Also, this assay was applied to liver samples taken from a biopsy material.

Extraction and preconcentration of formaldehyde in water by polypyrrole-coated magnetic nanoparticles and determination by high-performance liquid chromatography

In this study, a simple and rapid extraction method based on the application of polypyrrole-coated Fe3 O4 nanoparticles as a magnetic solid-phase extraction sorbent was successfully developed for the extraction and preconcentration of trace amounts of formaldehyde after derivatization with 2,4-dinitrophenylhydrazine. The analyses were performed by high-performance liquid chromatography followed by UV detection. Several variables affecting the extraction efficiency of the formaldehyde, i.e., sample pH, amount of sorbent, salt concentration, extraction time and desorption conditions were investigated and optimized. The best working conditions were as follows: sample pH, 5; amount of sorbent, 40 mg; NaCl concentration, 20% w/v; sample volume, 20 mL; extraction time, 12 min; and 100 μL of methanol for desorption of the formaldehyde within 3 min. Under the optimal conditions, the performance of the proposed method was studied in terms of linear dynamic range (10-500 μg/L), correlation coefficient (R(2) ≥ 0.998), precision (RSD% ≤ 5.5) and limit of detection (4 μg/L). Finally, the developed method was successfully applied for extraction and determination of formaldehyde in tap, rain and tomato water samples, and satisfactory results were obtained.

Investigation on formaldehyde release from preservatives in cosmetics

OBJECTIVE

To understand formaldehyde residue in cosmetics, an investigation on formaldehyde release from eight preservatives (methenamine - MA, paraformaldehyde - PF, poly(p-toluenesulfonamide-co-formaldehyde) -PTSAF, quaternium-15 - QU, imidazolidinyl urea - IU, diazolidinyl urea - DU, dimethyloldimethyl hydantoin - DMDM and bronopol - BP) under various conditions was performed.

METHODS

The concentration of released formaldehyde was determined by high-performance liquid chromatography with photodiode array detection after derivatization with 2,4-dinitrophenylhydrazine.

RESULTS

The amounts of formaldehyde release were in the order of PF > DU > DMDM ≈ QU ≈ IU > MA > BP > PTSAF. The releasing amounts of formaldehyde were the highest in the presence of aqueous matrices for the releasers except QU and IU, and the releasing effect was also relative to pH. More formaldehyde was released with longer storage time and higher temperature. Furthermore, all preservatives in cosmetic matrices released fewer amounts of formaldehyde than in pure aqueous or organic matrices, and the formaldehyde-releasing amounts were also cosmetic specific.

CONCLUSION

Formaldehyde release was dependent on the matrix, pH, time and mainly temperature, and the releasing effect was also cosmetic specific.

Experimental design and machine learning strategies for parameters screening and optimization of Hantzsch condensation reaction for the assay of sodium alendronate in oral solution

An experimental design was adopted to attain the optimum reaction parameters of chemical derivatization of anhydrous sodium alendronate in an oral solution formulaviaHantzsch condensation reaction.