A 96-position sample preparation procedure based on miniaturized stir bar sorptive dispersive microextraction for the determination of bladder cancer biomarkers in human serum

Bioanalysis requires high-throughput methodologies due to the elevated number of samples that must be treated daily in order to obtain the results on time. In this sense, an excellent approach is the employment of platforms that allow the treatment of parallel samples. In this work, a 96-well plates-based multiposition platform has been employed in miniaturized stir bar sorptive dispersive microextraction (mSBSDME) to determine two short-chain acylcarnitines (isobutyrylcarnitine (isoC4) and valerylcarnitine (C5)), as bladder cancer biomarkers, in serum samples. As extraction material, a magnetic composite made of nanoparticles embedded on a strong cation exchange polymer (CoFe 2 O 4 -SCX) was used. External calibration employing deuterated isobutyrylcarnitine (isoC4-d 9 ) as surrogate was used. Under optimized conditions, the limits of detection were in the low ng mL −1 level (0.1 and 0.3 ng mL −1 ), extraction efficiencies were 32 and 37 %, and precision ranged between 5 and 14 %. Relative recoveries were calculated at two concentration levels, obtaining values ranging from 95 to 120 %, demonstrating that matrix effect was negligible. To assess the utility of the developed method, serum samples from 5 volunteers were subdued to the mSBSDME proposed method, quantifying both analytes in all of them. Furthermore, the method was compared with previous reported approaches with the same purpose, obtaining considerably improvements specially in terms of throughput. The minimal sample and solvent requirements, along with the short analysis time, make this method particularly suitable for routine clinical and biomedical laboratories demanding for high throughput methodologies. • Acylcarnitine-type biomarkers of bladder cancer are determined in serum samples. • Miniaturized stir bar sorptive dispersive microextraction matches to small samples. • A high-throughput is achieved through a 96-position multiextraction platform. • A magnetic strong cation exchange material has been efficiently employed as sorbent. • The utility of the method is proved by the analysis of samples from 5 volunteers.