This study describes a novel approach for the simultaneous determination of CBS-X and CXT as widely used optical brighteners in household detergent, by combining the advantage of the high sensitivity of molecular fluorescence, and the selectivity of second-order chemometric methods. The proposed method is assisted by second-order chemometric analyses employing the PARAFAC, SWATLD and APTLD that help us to determine CBS-X and CXT in laundry powders and environmental samples, through the unique decomposition of the three-way data array. Proposed method can provide the extraction of relative concentrations of the analytes, as well as the spectral profiles. This approach achieves the second-order advantage and in principle could be able to overcome the spectral uncalibrated interference problems in the determination of CBS-X and CXT at the ng g−1 level. By spiking the known concentrations of these compounds to the real samples, the accuracy of the proposed methods was validated and recoveries of the spiked values were calculated. High recoveries (90.00%–113.33%) for the spiked laundry powders and real environmental samples indicate the present method successfully faces this complex challenge without the necessity of applying separation and preconcentration steps in environmental contaminations. Display omitted •Simultaneous determination of CBS-X and CXT in the laundry powders and environmental samples•Handling the direct interfering effect of a complex matrix by modeling system in the presence of uncalibrated interference•Discriminating between CBS-X and CXT by employing trilinear second-order calibration•Unique decomposition of the three-way data array by PARAFAC, SWATLD and APTLD