Interinstrumental method transfer of a capillary electrophoretic separation of angiotensin II and five derivatives: Evaluation and update of earlier developed guidelines

Abstract

The increased interest in the separation of peptides, proteins, immunoglobulins, and polynucleotides, led to an increased demand for appropriate analytical methodologies and instrumentation. CE, because of its unique separation mechanism and high efficiency, is frequently used in the analysis of those molecules. In this study, a CE method for the separation of six angiotensin analogues was developed in the first step. In the second step, the method was transferred to a CE instrument of another brand, taking into account guidelines defined earlier about the interinstrumental transfer of CE methods. Although previously successful, the application of these guidelines during this study was not able to maintain the baseline separation. Further research on the instrumental differences revealed that the electrical resistance on both instruments differed. At constant current, the electrical resistance, generated voltage, and separation efficiency on the Agilent instrument were lower than on the Beckman instrument. Increase of the electrical resistance, by reducing the capillary temperature, leads to an increased applied voltage and separation efficiency on the Agilent system. The guidelines developed earlier were, therefore, updated with an additional step equalizing the electrical resistances, which led to a successful interinstrumental analytical method transfer for the separation of six angiotensin derivatives.

Recent developments in capillary and microchip electroseparations of peptides (2015–mid 2017)

“…Special composition of the BGE (25 mM boric acid, 1 mM CuSO 4 , and 3 mM tartaric acid, pH 10.0) was used as a first choice for separation of angiotensin II and its five derivatives with the aim to improve sensitivity of peptides via biuret reaction . Because of incomplete separations of three angiotensin derivatives and high level of noise and bad peak shape under these conditions, finally, this mixture was completely separated in 25 mM citric acid BGE, pH 4.0, in bare FS capillary (75 μm id, 40/50 cm effective/total length) at 25 kV, with 217 nm wavelength of the UV‐detector.…”

Interinstrumental transfer of a fast short‐end injection capillary electrophoresis method: Application to the separation of niobium, tantalum, and their substituted ions

“…The reduction of the applied voltage led furthermore to similar electrical resistances, being 0.45 Ω on both instruments, therefore the capillary temperature was allowed to be kept identical at 31.0°C and was not reduced as recommended in De Cock et al. . Although the applied voltage was reduced, thus potentially leading to a lower separation efficiency and longer migration times as shown in Eq.…”

“…On the other hand, the separation efficiency did reduce. The application of earlier defined guidelines [, ], such as adapting injection parameters, ensuring identical capillary electrical resistances, and keeping the detector‐ and data‐handling parameters as constant as possible, did not result in a baseline separation of all substituted ions after transfer to the Agilent instrument as illustrated in Fig. .…”

Recent advances in capillary electrophoretic migration techniques for pharmaceutical analysis (2013–2015)

“…Strategies for method development, validation, and aspects of good instrument qualification are meanwhile clearly defined . An interesting recent work showed that inter‐instrumental method transfer is certainly possible for the GXP environment as well . However, since the thermostatting systems vary from one instrument type to another, it sometimes does not suffice to just use the same temperature settings.…”