New analytical methods for the determination of sulfur species with microextraction techniques: a review

This review discusses microextraction methods that have been published over the past twenty years for the determination of organic and inorganic sulfur species. The main advantages and disadvantages of the proposed microextraction methods for the determination of sulfur species are presented. The methods are compared in regard to several analytical parameters, such as sensitivity, selectivity and compliance with the requirements of green chemistry. The rate of occurrence of the selected types of microextraction methods and detection techniques is also discussed. Microextraction methods are often used to determine various organic sulfur species. These methods are primarily SPME and HS–SPME, which combine well with chromatographic techniques, especially GC–MS, GC–FID and HILIC–MS. Liquid microextraction methods, such as HS–SDME, DLLME and DI–SDME, are most often used to determine inorganic sulfur species and are combined with UV-Vis spectrophotometry, less often with HPLC or GC. Microextraction is an effective method for the determination of organic and inorganic sulfur species in real samples with a complex matrix. DLLME, HS–SDME and HS–SPME microextraction seem to us to be the most promising for the development of new methods for the determination of various sulfur species.Abbreviations: AED – atomic emission detector; CV – cyclic voltammetry; DAD – diode-array detector; DI–SDME – direct-immersion single-drop microextraction; DI–SPME – direct-immersion solid-phase microextraction; DLLME – dispersive liquid–liquid microextraction; ECD – electrochemical detection; ECLD – electrochemiluminescence detection; FAAS – flame atomic absorption spectrometry; FID – flame ionization detector; FPD – flame photometric detector; GC – gas chromatography; GDM – gas-diffusion microextraction; HF–LPME – hollow-fiber liquid-phase microextraction; HILIC – hydrophilic interaction chromatography; HLLME–FA – homogeneous liquid–liquid microextraction via flotation assistance; HPLC – high-performance liquid chromatography; HS–LPME – headspace liquid-phase microextraction; HS–SDME – headspace single-drop microextraction; HSSE – headspace sorptive extraction; HS–SPME – headspace solid-phase microextraction; HS–TFME – headspace thin-film microextraction; LC – liquid chromatography; LLE – liquid–liquid extraction; LOD – limit of detection; MS – mass spectrometry; PDMS – polydimethyl-siloxane; PFPD – pulsed flame photometric detector; QuEChERS – 'quick, easy, cheap, effective, rugged, and safe', a solid-phase extraction technique; RSD – relative standard deviation; SALLME – salting-out-assisted liquid–liquid microextraction; SAs – sulfonamides; SCD – sulfur chemiluminescence detector; SERS – surface-enhanced Raman spectrometry; SNC – smartphone nanocolorimetry; SPE – solid-phase extraction; SPMMTE – solid-phase membrane micro-tip extraction; TD – turbidimetric detection; UHPLC – ultrahigh-performance liquid chromatography; USAE–ME – ultrasound-assisted emulsification microextraction; UV-Vis – ultraviolet–visible spectroscopy.Highlights Microextraction methods used to determine organic and inorganic sulfur species are describedMicroextraction combined with chromatographic, spectroscopic and electroanalytical detection techniques are reviewedAnalytical characteristics and trends in the development of microextraction methods for the determination of sulfur species are discussed