The invention provides methods for quantifying a non-ionic surfactant in a composition comprising a polypeptide and the non-ionic surfactant, where the quantification exhibits reduced interference between the non-ionic surfactant and the polypeptide. Also provided are methods where the composition further includes N-acetyl tryptophan, and the quantification exhibits reduced interference between the non-ionic surfactant, the polypeptide, and N-acetyl tryptophan.

The invention provides methods for quantifying a non-ionic surfactant in a composition comprising a polypeptide and the non-ionic surfactant, where the quantification exhibits reduced interference between the non-ionic surfactant and the polypeptide. Also provided are methods where the composition further includes N-acetyl tryptophan, and the quantification exhibits reduced interference between the non-ionic surfactant, the polypeptide, and N-acetyl tryptophan.

The present invention relates to a dianhydride analysis method, which can reliably analyze a dianhydride having high reactivity and low solubility. In addition, the present invention can analyze the structure of impurities by separating the impurities on the basis of having a similar retention time in HPLC analysis, and can analyze the purity of the dianhydride with or without chromophores.

The present invention relates to a dianhydride analysis method, which can reliably analyze a dianhydride having high reactivity and low solubility. In addition, the present invention can analyze the structure of impurities by separating the impurities on the basis of having a similar retention time in HPLC analysis, and can analyze the purity of the dianhydride with or without chromophores.

A sample injector for use in a fluid separation system for separating compounds of a fluidic sample in a mobile phase, the sample injector comprising a switchable valve, a sample loop in fluid communication with the valve and configured for receiving the fluidic sample, a metering device in fluid communication with the sample loop and configured for introducing a metered amount of the fluidic sample on the sample loop, and a control unit configured for controlling switching of the valve to transfer the sample loop between a low pressure state and a high pressure state via an intermediate state and for controlling the metering device during the intermediate state to at least partially equilibrate a pressure difference in the sample loop between the low pressure state and the high pressure state.

A sample injector for use in a fluid separation system for separating compounds of a fluidic sample in a mobile phase, the sample injector comprising a switchable valve, a sample loop in fluid communication with the valve and configured for receiving the fluidic sample, a metering device in fluid communication with the sample loop and configured for introducing a metered amount of the fluidic sample on the sample loop, and a control unit configured for controlling switching of the valve to transfer the sample loop between a low pressure state and a high pressure state via an intermediate state and for controlling the metering device during the intermediate state to at least partially equilibrate a pressure difference in the sample loop between the low pressure state and the high pressure state.

The invention provides methods for quantifying a non-ionic surfactant in a composition comprising a polypeptide and the non-ionic surfactant, where the quantification exhibits reduced interference between the non-ionic surfactant and the polypeptide. Also provided are methods where the composition further includes N-acetyl tryptophan, and the quantification exhibits reduced interference between the non-ionic surfactant, the polypeptide, and N-acetyl tryptophan.

The invention provides methods for quantifying a non-ionic surfactant in a composition comprising a polypeptide and the non-ionic surfactant, where the quantification exhibits reduced interference between the non-ionic surfactant and the polypeptide. Also provided are methods where the composition further includes N-acetyl tryptophan, and the quantification exhibits reduced interference between the non-ionic surfactant, the polypeptide, and N-acetyl tryptophan.

Exemplary embodiments are directed to devices, methods and systems capable of pressurization, generally involving a flow system that includes a pressurized reservoir, at least one pump including a pump control valve, an outlet port, a shut-off valve and a vent valve. The flow system is configured to be pressurized. The shut-off valve is disposed between the pressurized reservoir and the at least one pump. The vent valve is disposed between the at least one pump and the outlet port. The shut-off valve, the vent valve and the pump control valve of the at least one pump are configured to actuate in a coordinated manner to control a pressurization of the flow system. Exemplary embodiments are further directed to devices, methods and systems for column switching, generally including at least a first column, a second column and a column switching valve.

Exemplary embodiments are directed to devices, methods and systems capable of pressurization, generally involving a flow system that includes a pressurized reservoir, at least one pump including a pump control valve, an outlet port, a shut-off valve and a vent valve. The flow system is configured to be pressurized. The shut-off valve is disposed between the pressurized reservoir and the at least one pump. The vent valve is disposed between the at least one pump and the outlet port. The shut-off valve, the vent valve and the pump control valve of the at least one pump are configured to actuate in a coordinated manner to control a pressurization of the flow system. Exemplary embodiments are further directed to devices, methods and systems for column switching, generally including at least a first column, a second column and a column switching valve.