Development of on-line spectroscopic determination approach of dispersive liquid–liquid microextraction based on an effective device

•An on-line determination method of DLLME was developed based on an effective device.•The volume of sample can conveniently change to perform a more effective DLLME.•The proposed device provided a repeatable and effective injection of the extractant.•The method was used to quantify a model analyte rhodamine B in three real samples.•The applicability of the method can be extended to other analytes.

A novel, rapid, simple, and low-cost on-line determination approach of dispersive liquid–liquid microextraction (DLLME) with low-density solvents was developed with the support of a specially designed effective homemade device. The proposed method surmounted the drawbacks of conventional DLLME of the need of high-density solvents as extractants, and the requirement of centrifugation operation to obtain phase separation, and the difficulties to realize on-line determination. The amount of sample utilized can conveniently change according to practical needs by varying the volume of the extraction tube of the device to perform a more effective DLLME. A case study was carried out to assess this method utilizing the dye rhodamine B as the model analyte. The experiment parameters influencing the extraction were systematically investigated. Under optimum conditions, the linearity was obtained in the range of 0.015–1.000 μg/mL with the correlation coefficient (r2) of 0.9980. The limit of detection and quantification were 6.1 and 20.4 μg/L, respectively. Good repeatability was achieved with the relative standard deviations (RSD) for five replicate measurements of different concentration samples less than 4.06%, and the presented method was successfully employed to quantify rhodamine B in three real samples.

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