i.prep 2 delivers linear tartrazine dilution performance at OD450.

The linearity result is driven by measured mean absorbance values of 2.835, 1.385, 0.765, 0.398, 0.212, and 0.114 OD across the six tartrazine standards, with blank wells A7:H7 averaging 0.032 OD. This produces a clear monotonic response over the full 1:2 dilution range.

The first-order fit reported by the byonoy absorbance 96 output was y = 0.0278306x + 0.0384111 with R^2 = 0.9994. Although higher-order or weighted fitting models could be applied to optimise a calibration curve, that is not necessary to show the performance of this dilution series.

When a straightforward linear model captures the series this well, it suggests that the dilution preparation and dispensing steps were executed consistently enough that the underlying relationship does not need mathematical help to appear well behaved. In this dataset, the quality of the i.prep 2 output is visible directly in the measured OD450 values rather than being recovered through more aggressive curve fitting.

Replicate consistency across the plate supports the same conclusion from a pipetting perspective. Each standard was present in eight wells, and the replicate values remain closely clustered within each concentration level, with absorbance CV ranging from 0.297% at the highest standard to 8.747% at the lowest standard where signal approaches the blank floor.

A more complex fit could reduce residuals slightly or improve back-calculated values at the lowest concentrations near the blank floor. That would massage the numbers, but it would not change the more important observation: i.prep 2 already produces a dilution series that is convincingly linear under a basic first-order regression.

This fit should be interpreted as evidence of strong dilution fidelity and repeatable pipetting within this assay configuration. It does not by itself constitute full validation of absolute volumetric accuracy, mixing performance under all conditions, or behaviour across other liquids, consumables, concentration ranges, or reader settings.