Distinction and quantification of carry-over and sample interaction in gas segmented continuous flow analysis

Area of Science:

• Analytical Chemistry
• Biochemistry

Background:

• Carry-over and sample interaction are critical factors affecting analytical system accuracy.
• Existing methods for quantifying these effects may not be sufficiently precise.

Purpose of the Study:

• To derive novel formulae for calculating carry-over and sample interaction.
• To validate and recommend optimal schemes for determining carry-over and sample interaction coefficients.
• To investigate the influence of operational parameters on carry-over and sample dispersion.

Main Methods:

• Derivation of mathematical formulae for carry-over and sample interaction.
• Verification of existing and proposal of new experimental schemes for coefficient determination.
• Experimental investigation of carry-over as a function of cycle time, sample time, and wash time.
• Analysis of sample dispersion as a function of sample time.

Main Results:

• New formulae for carry-over and sample interaction are presented.
• A scheme of two low, one high, and one low concentration sample is recommended for carry-over coefficient determination.
• Commonly used schemes were found to measure the sum of carry-over and sample interaction coefficients.
• A scheme of three low and one high concentration sample is proposed for sample interaction coefficient determination.
• Carry-over is strongly dependent on cycle time and weakly on the sample-to-wash time ratio.
• Sample dispersion is dependent on sample time.
• Fitted equations allow prediction of carry-over, absorbance, and dispersion.

Conclusions:

• Intersample air segmentation significantly reduces carry-over, sample interaction, and dispersion.
• The derived formulae and proposed schemes enhance the accuracy of analytical measurements.
• Understanding and controlling these parameters are crucial for optimizing analytical system performance.