A simple smartphone-based digital image colorimetry is proposed for the determination of vancomycin in drugs. The analytical method relied on the reaction of vancomycin with copper(II) in ethanol–water medium with pH 4.3. The reaction resulted in the formation of a blue–grey complex, presenting an absorption maximum at 555 nm. A mobile application was used for smartphone-based analysis to decompose the individual channels of the colour model representations. The determination was performed using three smartphones followed by a comparison of the outcomes with spectrophotometric measurements. The most optimal analytical parameters were achieved for the H channel. The linear ranges obtained for the smartphone-based method proved to be comparable to the spectrophotometric range of 0.044–1.500 g dm⁻³ and were 0.049–1.500 g dm⁻³, 0.057–1.500 g dm⁻³, and 0.040–1.500 g dm⁻³ for Smartphones 1–3, respectively. Moreover, the determined coefficients of variance (CV, n = 9) and limits of detection (LOD) were 2.3% and 0.015 g dm⁻³, 6.2% and 0.017 g dm⁻³, and 2.5% and 0.012 g dm⁻³, respectively. Whereas for spectrophotometry, the obtained precision, CV was of 0.9% and a LOD of 0.013 g dm⁻³. The accuracy of the method was verified using model samples, generally the results were obtained with accuracy better than 10.9% (relative error). The method was applied to the determination of vancomycin in drugs. The results obtained by smartphone-based colorimetry did not differ from the expected values for more than 2.6%, were consistent with each other and with the results of spectrophotometric determinations. Graphical abstract

An automated flow analysis-solid phase extraction (FA-SPE) system and methodology of ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) analysis were developed for the determination of selected antiviral drugs (acyclovir, amantadine, rimantadine, and oseltamivir) in water samples. The proposed FA-SPE approach enables the integration of various extraction stages and elimination of the sample evaporation step and offers individual customisation of SPE parameters, inter alia sample, and eluate flow rate and volume. Using the developed FA-SPE procedure, e.g. a 100-fold preconcentration of the target analytes in 1 h was achieved. A method for chromatographic analysis was also developed to determine the selected antiviral drugs in combination with the use of the FA-SPE system. The developed FA-SPE UHPLC-MS/MS method was validated including the determination of linearity of analytical graphs, limits of detection (5.5–99.9 pg mL⁻¹) and quantification (18.3–329.8 pg mL⁻¹), intra-day (1.8–8.3%) and inter-day (3.0–9.2%) precision, recovery (95.6–105.3%), and matrix effects (− 12.9 to 13.2%). The proposed method was successfully applied to analyse tap, drinking, and river water samples, revealing the presence of amantadine at a concentration of 40.1 pg mL⁻¹ in one sample. The environmental impact of the developed FA-SPE sample preparation procedure was also assessed using the AGREEprep metric tool and compared with five other literature methods, achieving the most sustainable outcome. Graphical abstract

Novel integrated flow-based steam distillation and titration system with spectrophotometric detection was developed for determination of volatile acidity in wines. Using the system, the distillation procedure was carried out in an automatic manner, starting with introducing into a heated steam distillation module a sample and subjecting it to steam distillation. Under selected conditions, all the analyte was transferred to the distillate; therefore, the system did not require calibration. The collected distillate and titrant were introduced into the next monosegments in varying proportions, in accordance with the developed titration procedure, and directed to the detection system to record the titration curve. The titration was stopped after reaching the end point of titration. Procedures for distillation and titration were developed and verified separately by distillation of acetic acid, acetic acid in the presence of tartaric acid as well as acetic acid, tartaric acid, and titratable acidity, with precision (relative standard deviation) and accuracy (relative error) for both procedures lower than 6.9 and 5.6%, respectively. The developed steam distillation and titration systems were used to determine volatile acidity in samples of white and rosé wines separately and as the integrated steam distillation and titration system, both with precision lower than 9.4% and accuracy better than 6.7%.