Development and validation of a new UHPLC method for related proteins in insulin and insulin analogues as an alternative to the European Pharmacopoeia RP-HPLC method

Enhancing anthocyanin extraction efficiency in vegetables and fruits: a high-speed shear homogenization technology

BACKGROUND

To extract anthocyanins with high efficiency, a hypothesis for high-speed shear homogenization extraction (HSHE) method was established through a combination of solvent and ultrasonic-assisted extractions. The efficacy of this hypothesis was demonstrated by performing qualitative and quantitative analyses of 16 anthocyanins extracted from five northern vegetables, and five berry fruits using ultra-high-performance Q-Exactive Orbitrap tandem mass spectrometry. Single-factor experiments were conducted by varying ethanol concentration, temperature, pH and extraction cycles to determine the optimal conditions for this method.

RESULTS

Optimal extraction conditions (ethanol 70-80%, 40-50 °C, pH 3-4, performed twice) were determined using an HSHE (5 min, 10 000 rpm, 25 °C) assisted shaker (60 min) and ultrasonication (40 kHz, 160 W cm-2, 30 min, 25 °C) procedure. Compared to the traditional non-HSHE method, the total anthocyanin content obtained through HSHE extraction showed a significant increase, ranging from 1.0 to 3.9 times higher, with purple cabbage exhibiting the most pronounced enhancement in content. More types of anthocyanins were detected in blueberry (9), black bean (7) and raspberry (5), of which malvidin was the major anthocyanin (0.426 g kg-1) in blueberry, having an amount five times than previously obtained.

CONCLUSION

The established HSHE method has been proven to be a superior technique for anthocyanin extraction, with higher extraction efficiency and concentrations. This technique also provides a new avenue for extracting bioactive compounds from diverse food sources, with potential applications in improving the functional properties of food products. © 2024 Society of Chemical Industry.

Simultaneous separation of insulin and six therapeutic analogues on a mixed mode column: HPLC-UV method development and application

Human insulin and six most used therapeutic analogues are very similar in terms of retention on a reversed-phase column. Thus, the LC methods prescribed in the European Pharmacopoeia monographs for insulin and insulin analogues include many similar separation methods, which tend to be time consuming when separating individual products of insulins or are inadequate when handling a mixture. In this study, we present a simple, robust, versatile and accessible HPLC-UV separation method for identification and quantification of human insulin and its analogues in one run. The simultaneous separation and detection is possible by fine-tuning the mobile phase properties that affect the separation mechanism on a mixed mode column combining anion exchange and reversed-phase characteristics. Also developed was a simple and effective SPE sample cleaning procedure with insulin recoveries ranging from 80 to 100% for all analogues. On the other hand, the concentration of major excipients such as phenol and m-cresol fall below 1%. The two developed and validated separation methods differ in their compatibility with the use of a quaternary or binary pump, thus enabling sample characterisation independent of the HPLC solvent delivery system. The methods are compatible with the use of a mass spectrometric detector for an indisputable identification.

Colorimetric detection of insulin in human serum using GO/AuNPs/TX-100 nanocomposite

In this study, graphene oxide/gold nanoparticles/Triton X-100 nanocomposites (GO/AuNPs/TX-100) were synthesized using the sonochemical method and their ability in ultrasound-assisted colorimetric detection of insulin was investigated. The synthesized GO/AuNPs/TX-100 nanocomposites were characterized by UV-visible absorption spectroscopy and TEM analysis. The interaction between the nanocomposites and insulin was observed by both naked eye and optical absorption spectroscopy. The GO/AuNPs/TX-100 nanocomposites displayed apparent color changes (red to blue) and absorption spectra changes (decreasing of the band around 528 nm and appearance of a new red-shifted band at 640 nm) in presence of insulin. The interaction mechanism of the nanocomposites and insulin was discussed. It is based on the special structure of insulin, that insulin can be easily self-assemble into the GO/AuNP/TX-100 nanocomposites and can also play the role of a bridge between two different GO/AuNPs/TX-100 nanocomposites by peptide chains. The effective parameters for insulin detection were optimized. The colorimetric method was used for quantification of insulin in the range of 2-300 ng mL^-1 with a detection limit of 0.1 ng mL^-1. Moreover, the relative standard deviation of the method was 3.1 and 2.7% (n = 10) at concentrations of 50 and 200 ng mL^-1, respectively on the same day and 4.8% at a concentration (200.0 ng mL^-1) on five consecutive days. The present method was utilized for insulin assay in human blood serums with satisfactory results.