Field Quantification of Hydroxyl Radicals by Flow-Injection Chemiluminescence Analysis with a Portable Device.

Hydroxyl radical (•OH) is a powerful oxidant abundantly found in nature and plays a central role in numerous environmental processes. On-site detection of •OH is highly desirable for real-time assessments of •OH-centered processes and yet is restrained by a lack of an analysis system suitable for field applications. Here, we report the development of a flow-injection chemiluminescence analysis (FIA-CL) system for the continuous field detection of •OH. The system is based on the reaction of •OH with phthalhydrazide to generate 5-hydroxy-2,3-dihydro-1,4-phthalazinedione, which emits chemiluminescence (CL) when oxidatively activated by H2O2 and Cu3+. The FIA-CL system was successfully validated using the Fenton reaction as a standard •OH source. Unlike traditional absorbance- or fluorescence-based methods, CL detection could minimize interference from an environmental medium (e.g., organic matter), therefore attaining highly sensitive •OH detection (limits of detection and quantification = 0.035 and 0.12 nM, respectively). The broad applications of FIA-CL were illustrated for on-site 24 h detection of •OH produced from photochemical processes in lake water and air, where the temporal variations on •OH productions (1.0-12.2 nM in water and 1.5-37.1 × 107 cm-3 in air) agreed well with sunlight photon flux. Further, the FIA-CL system enabled field 24 h field analysis of •OH productions from the oxidation of reduced substances triggered by tidal fluctuations in coastal soils. The superior analytical capability of the FIA-CL system opens new opportunities for monitoring •OH dynamics under field conditions.

Rapid and Online Microvolume Flow-Through Dialysis Probe for Sample Preparation in Veterinary Drug Residue Analysis.

A rapid and online microvolume flow-through dialysis probe designed for sample preparation in the analysis of veterinary drug residues is introduced. This study addresses the need for efficient and green sample preparation methods that reduce chemical waste and reagent use. The dialysis probe integrates with liquid chromatography and mass spectrometry (LC-MS) systems, facilitating automated, high-throughput analysis. The dialysis method utilizes minimal reagent volumes per sample, significantly reducing the generation of solvent waste compared to traditional sample preparation techniques. Several veterinary drugs were spiked into tissue homogenates and analyzed to validate the probe's efficacy. A diagnostic sensitivity of >97% and specificity of >95% were obtained for this performance evaluation. The results demonstrated the effective removal of cellular debris and particulates, ensuring sample integrity and preventing instrument clogging. The automated dialysis probe yielded recovery rates between 27 and 77% for multiple analytes, confirming its potential to streamline veterinary drug residue analysis, while adhering to green chemistry principles. The approach highlights substantial improvements in both environmental impact and operational efficiency, presenting a viable alternative to conventional sample preparation methods in regulatory and research applications.

Biochar nanosphere-functionalized carbon fibers for in-tube solid-phase microextraction of polycyclic aromatic hydrocarbons in environmental water followed by liquid chromatography and diode array detection.

In order to improve the extraction ability of carbon fibers (CFs) for microextraction of polycyclic aromatic hydrocarbons (PAHs), biochar nanospheres derived from glucose were in-situ grown onto the surface of CFs via hydrothermal synthesis. The surface morphology and elemental composition of biochar nanospheres-CFs were investigated by scanning electron microscopy and X-ray photoelectron spectroscopy. Thereafter, the biochar nanosphere-CFs were pulled into the polyetheretherketone tube for solid-phase microextraction, and the tube was combined with high-performance liquid chromatography-diode array detector to online detect PAHs. With the help of π-stacking, hydrophobic, and hydrophilic effect of biochar nanospheres, the extraction efficiency of CFs was greatly enhanced (enrichment factor increased by 293% compared with  the original). The conditions affecting the analytical performance (sampling volume, sampling rate, methanol content, and desorption time) were investigated. Under the optimal conditions, an online analytical method for microextraction and determination of several PAHs was developed, and satisfactory results were achieved. The limits of detection were 0.003-0.010 ng mL-1 owing to high enrichment effect (2973-3600), linearity ranged from  0.010-15.0 ng mL-1, and relative standard deviations were 0.4%-1.6% (intra-day) and 2.4%-4.4% (inter-day), respectively. The method was applied to analyze environmental water samples (rain water, snow water, and river water), and spiked recoveries within 80.0%-119% were obtained.

ß-Ketoenamine-linked covalent organic framework absorbent for online micro-solid phase extraction of trace levels bisphenols in plastic samples.

Covalent organic frameworks with tunable porous crystallinity and outstanding stability have exhibited fascinating pretreatment performance as ideal extraction media. Herein, the ß-ketoenamine-linked TpPa-1 synthesized by 1,3,5-triformylphloroglucinol and paraphenylenediamine was employed as the absorbent for online micro-solid phase extraction of trace bisphenols combined with high-performance liquid chromatography detection. A series of characterizations indicated that the TpPa-1 possessed large surface areas, high stability, and hydrophobicity. The main experimental parameters affecting the extraction efficiency were optimized in detail. Compared with four commercial sorbents, the TpPa-1 exhibited superior enrichment capacity for extracting bisphenols. Under the optimum conditions, the established method demonstrated a wide linear range and high sensitivity with the limit of detection ranging from 0.05-0.06 µg/L. Furthermore, the developed method was successfully applied to determine bisphenols in plastic samples. Bisphenol A was actually detected in a transparent box with a concentration of 0.31 µg/g, and the recoveries of the four bisphenols in the plastic samples were 80.5-116% with the relative standard deviation less than 9.2%. Such performance was attributed to recognition affinity, including the π-π affinity, hydrophobic effect, and hydrogen bond. These results demonstrated that TpPa-1 possessed great potential to be an excellent pretreatment medium for online separation and analysis of trace analytes in complex samples.

Titania hybridized melamine-formaldehyde aerogel for online in-tube solid-phase microextraction of polycyclic aromatic hydrocarbons prior to HPLC-DAD.

In order to improve the selectivity and stability of melamine-formaldehyde (MF) aerogel, it was composited with TiO2 aerogel. A TiO2-MF hybrid aerogel was in situ prepared on the surface of carbon fibers for in-tube solid-phase microextraction (SPME). The extraction performance of TiO2-MF aerogel was regulated by changing the ratio of TiO2 sol and MF sol during the material preparation. Coupled with high-performance liquid chromatography-diode array detection (HPLC-DAD), the extraction tube filled by TiO2-MF aerogel-coated carbon fibers was evaluated with several types of environmental pollutants including polycyclic aromatic hydrocarbons (PAHs), estrogens, and ultraviolet filters. Because of favourable extraction performance of PAHs they were selected as model analytes, and some important influence factors were optimized for satisfactory sensitivity. The detection limits were in the range 0.05-0.10 µg L-1, owing to high enrichment factors (653-1007). The online in-tube SPME-HPLC-DAD method was verified for the determination of trace PAHs in environmental water samples, and acceptable recovery (70-118%) was achieved. The analytical methods also displayed some advantages in comparison with other reports. Moreover, the extraction tube exhibited satisfactory chemical stability.

Resorcinol-formaldehyde aerogel coating for in-tube solid-phase microextraction of estrogens.

Resorcinol-formaldehyde aerogel coating was in situ prepared on the surface of basalt fibers. The aerogel coating is uniformly modified onto basalt fibers, and it is very porous according to the characterization by using scanning electron microscopy. An extraction tube was prepared for in-tube solid-phase microextraction by placing the aerogel-coated basalt fibers into a polyetheretherketone tube. To evaluate the extraction performance toward five estrogenic compounds, the tube was connected with high performance liquid chromatography, the important extraction and desorption conditions were investigated. An online analytical method for detection of estrogens was developed and presented low limits of detection (0.005-0.030 µg/L), wide linear ranges (0.017-20, 0.033-20, and 0.099-20 µg/L), good linearity (r > 0.9990), and satisfactory repeatability (relative standard deviation < 2.7%). The method was successfully applied to detect trace estrogens in real water samples (bottled pure water and bottled mineral water), satisfactory recoveries were ranged from 80 to 125% with two spiking levels of 2 and 6 µg/L.

Application of biocharcoal aerogel sorbent for solid-phase microextraction of polycyclic aromatic hydrocarbons in water samples.

A facile method was introduced for preparing a biocharcoal aerogel, which was derived from pomelo peel as the only raw material. The inner spongy layer of pomelo peel was freeze-dried for maintaining three-dimensional structure and then carbonized under high temperature and oxygen-limited conditions. The morphological structure and graphitization degree of biocharcoal aerogel were characterized using a scanning electron microscope and Raman spectrum. After sifting and grinding, the biocharcoal aerogel as an adsorbent was coated onto the surface of stainless steel wires. Through placing the wires into a polyetheretherketone tube, the in-tube solid-phase microextraction device was obtained. Coupled with high-performance liquid chromatography, it exhibited good extraction performance for polycyclic aromatic hydrocarbons, then an online analytical method was established with low limits of detection (0.005-0.050 ng/mL), wide linear ranges (0.017-15 ng/mL) with superior correlation coefficients higher than 0.9990, high enrichment factors (1128-3425), and acceptable intra- and inter-day repeatabilities (relative standard deviations ≤ 6.7%, n = 3). The method was applied to detect polycyclic aromatic hydrocarbons in bottled water samples, environmental water samples, and soft drinks with satisfactory recoveries (83.3-120.9%). This research not only developed a new carbon aerogel but also evaluated its adsorption performance in sample preparation.

Triazine-based organic polymers@SiO2 nanospheres for sensitive solid-phase microextraction of polycyclic aromatic hydrocarbons.

Triazine-based organic polymers@SiO2 nanospheres were prepared and applied as an extraction coating onto stainless steel wires and the wires were filled into polyetheretherketone tube for in-tube solid-phase microextraction. Taking polycyclic aromatic hydrocarbons as targets, main factors affecting extraction performance of the tube were investigated through coupling to high performance liquid chromatography. Under the optimum conditions, an online analytical method for polycyclic aromatic hydrocarbons was established with large linear ranges (0.010-20 µg/L), low limits of detection (0.003-0.010 µg/L), high enrichment factors (533-2954), and good repeatability (relative standard deviations <1.7% for intraday test, <5.0% for interday test). The analysis method was successfully applied to the detection of trace targets in real water samples and the relative recoveries ranged from 82.9 to 119.9%, which demonstrated the applicability of extraction tube in sample preparation.

Continuous Monitoring of Air Purification: A Study on Volatile Organic Compounds in a Gas Cell.

Air pollution is one of the major environmental issues that humanity is facing. Considering Indoor Air Quality (IAQ), Volatile Organic Compounds (VOCs) are among the most harmful gases that need to be detected, but also need to be eliminated using air purification technologies. In this work, we tackle both problems simultaneously by introducing an experimental setup enabling continuous measurement of the VOCs by online absorption spectroscopy using a MEMS-based Fourier Transform infrared (FTIR) spectrometer, while those VOCs are continuously eliminated by continuous adsorption and photocatalysis, using zinc oxide nanowires (ZnO-NWs). The proposed setup enabled a preliminary study of the mechanisms involved in the purification process of acetone and toluene, taken as two different VOCs, also typical of those that can be found in tobacco smoke. Our experiments revealed very different behaviors for those two gases. An elimination ratio of 63% in 3 h was achieved for toluene, while it was only 14% for acetone under same conditions. Adsorption to the nanowires appears as the dominant mechanism for the acetone, while photocatalysis is dominant in case of the toluene.

Application of Covalent Organic Porous Polymers-Functionalized Basalt Fibers for in-Tube Solid-Phase Microextraction.

To establish an online analytical method towards estrogenic pollutants, a covalent organic porous polymer (COP) was in-situ synthesized on the surface of basalt fibers (BFs) for in-tube solid-phase microextraction (IT-SPME). The extraction tube, obtained via placing the modified BFs into a polyetheretherketone tube, was combined with high-performance liquid chromatography (HPLC) to achieve online IT-SPME-HPLC analysis. The important parameters, including sampling volume, sampling rate, organic solvent content and desorption time, were carefully investigated. Under the optimized conditions, the online analytical method was established for five estrogenic targets, with low limits of detection (0.001-0.005 µg/L), high enrichment factors (1800-2493), wide linear ranges (0.003-20, 0.015-20 µg/L) and satisfactory repeatability. It was successfully applied to detect five estrogens in a wastewater sample and a water sample in a polycarbonate cup. The BFs functionalized with COPs displayed excellent extraction effect for estrogenic pollutants, furthermore it has great potential in sample preparation or other fields.

An online field-assisted micro-solid-phase extraction device coupled with high-performance liquid chromatography for the direct analysis of solid samples.

Herein, a total online device based on field-assisted extraction (FAE), micro-solid-phase extraction (µ-SPE), and high-performance liquid chromatography (HPLC) was designed. Solid samples were pretreated with ultrasound-microwave synergic effects, and then the extract was cleaned up online with a monolithic column, followed by HPLC analysis. The cross-actions between ultrasound and microwave along with other extraction parameters were studied systematically. The efficiency of this online method was verified in the determination of polycyclic aromatic hydrocarbons (PAHs) in foods and tetracycline antibiotics (TCAs) in cosmetic samples. The detection limits of nine PAHs including fluorene, phenanthrene, anthracene, fluoranthene, benzo[k]fluoranthene, benz[a]anthracene, benzo[b]fluoranthene, pyrene, and benzo[a]pyrene were all within 0.075-0.30 µg/kg, as well as four TCAs including oxytetracycline, tetracycline, chlortetracycline, and doxycycline were within 0.02-0.06 µg/kg. Six PAHs were found in roast potatoes and baked fish and the recoveries were in the range of 71.5-119.7% with RSDs of 0.2-10.9% (n = 3). The recoveries for TCAs in cosmetic samples were in the range of 75.3-118.0% with RSDs lower than 8.2% (n = 3). Compared with those offline methods, this total online FAE-µ-SPE-HPLC method not only simplifies the operation process, but also increases the precision and accuracy. Beyond trace analytes analysis in solid and semi-solid matrixes, application of this total online analysis method can also be extended to investigate field-assisted extraction mechanisms. Graphical abstract.

Nano-MoO3 for highly selective enrichment of polycyclic aromatic hydrocarbons in in-tube solid-phase microextraction.

Nano-molybdenum trioxide was prepared from nano-molybdenum disulfide by simple firing in muffle furnace. Nano-molybdenum trioxide was used as the extraction coating on the stainless steel wire. Four wires were filled in a polyetheretherketone tube to get an extraction tube. The tube was connected to the six-port valve of a high performance liquid chromatograph, and the online analysis system was constructed. Extraction selectivity of the tube for different types of compounds, including polycyclic aromatic hydrocarbons, plasticizers, estrogens, anilines and neonicotinoids, was studied. Good enrichment ability for polycyclic aromatic hydrocarbons, but the extraction efficiency of others was not satisfactory. Using eight polycyclic aromatic hydrocarbons as the targets, an analytical method was established after optimizing main factors such as sampling volume, sampling rate, methanol content, and desorption time. The established method exhibited wide linear range to 0.016-20.00 µg/L and low limits of detection to 0.005 µg/L, and the enrichment factors can be up to 2443. The method was applied to the detection of trace polycyclic aromatic hydrocarbons in tap water and river water, and a good recovery was obtained. The tube showed good durability and chemical stability, and it still remained good extraction effect after more than 140 run.

Carbonized cotton fibers via a facile method for highly sensitive solid-phase microextraction of polycyclic aromatic hydrocarbons.

Cotton fiber is an environmentally friendly and natural material with a certain extraction capacity, while its enrichment ability is poor. In order to improve the extraction efficiency of cotton fibers, it was carbonized to form a layer of amorphous carbon as the sorbent by a simple carbonization method. Carbonized cotton fibers were filled into a polyetheretherketone tube for in-tube solid-phase microextraction. The carbonization time was investigated to obtain high extraction efficiency. Coupled to high-performance liquid chromatography, the extraction tube was evaluated with polycyclic aromatic hydrocarbons, estrogens and phthalates, and it exhibited best extraction efficiency for polycyclic aromatic hydrocarbons. Under the optimum conditions, an online analysis method for several polycyclic aromatic hydrocarbons was established with large linear ranges (0.016-0.20 µg/L), low limits of detection (0.005-0.020 µg/L), and high enrichment factors (948-2874). Analysis method was successfully applied to the detection of targets in the real samples and shown satisfactory durability and chemical stability. Moreover, the relative recoveries ranged from 82 to 119.2%, which demonstrated the applicability of carbonized cotton fibers in sample preparation. Compared with other reported methods, the proposed method provided shorter extraction time, higher enrichment factors, comparable limits of detection, and recoveries.

Polydopamine-coated cotton fibers as the adsorbent for in-tube solid-phase microextraction.

Polydopamine was coated onto cotton fibers as the adsorbent to improve the extraction efficiency. Polydopamine-coated cotton fibers were placed into a polyetheretherketone tube for in-tube solid-phase microextraction. To develop an online analysis system, the extraction tube was connected with high-performance liquid chromatography. The tube was evaluated with five estrogenic analytes, and the extraction and desorption conditions were optimized to get high extraction efficiency. Under the optimum conditions, the enrichment factors of five analytes were 143-1745. An online analysis method was established, it had large linear ranges (0.10-40 and 0.16-40 µg/L), low limits of detection (0.03, 0.05 µg/L) and satisfactory repeatability (≤3.2%). The analysis method was applied to detect targets in the real samples like as hot water in new plastic cup and tap water. The relative recoveries spiked at 1 and 5 µg/L in these samples were investigated and the results were in the range of 83.7-109%.

Carbonized silk fibers for in-tube solid-phase microextraction to detect polycyclic aromatic hydrocarbons in water samples.

Silk fibers were carbonized to develop a biomass carbon material as an adsorbent for solid-phase microextraction. The surface structure of the carbonized silk fibers was characterized by scanning electron microscopy, and the graphitization degree was determined by Raman spectrometry. After carbonization under high temperature, the orderliness and structural regularity of carbon atoms on silk fibers were promoted. Extraction tube packed with carbonized silk fibers was prepared for in-tube solid-phase microextraction. Coupled with high performance liquid chromatography, it exhibited good extraction performance for hydrophobic polycyclic aromatic hydrocarbons. Main parameters including sampling volume, sampling rate, methanol content in sample, and desorption time were systematically investigated. Under the optimum conditions, the analysis method was established and it exhibited wide linear range (0.016-20 µg/L) with good linearity (correlation coefficient ≥ 0.9947), low limits of detection (0.005-0.050 µg/L), and high enrichment factors (1189-2775). Relative standard deviations (n = 3) for intraday (≤3.3%) and interday (≤9.6%) tests indicated that the extraction material had satisfactory repeatability. Finally, the analytical method was successfully applied to detect trace polycyclic aromatic hydrocarbons in real water samples, demonstrating its satisfactory practicability.

A green extraction material - natural cotton fiber for in-tube solid-phase microextraction.

Natural cotton fiber was applied as a green extraction material for in-tube solid-phase microextraction. Cotton fibers were characterized by scanning electron microscope. A bundle of cotton fibers (685 mg, 20 cm) was directly packed into a polyetheretherketone tube (i.d. 0.75 mm) to get the extraction device. It was connected into high performance liquid chromatography, building an online extraction and dectection system. Through the online analysis system, several polycyclic aromatic hydrocarbons were used as the targets to evaluate the extraction performace of the device. In order to get high extraction efficiency and sensitivity, the extraction and desorption conditions were optimized. Under the optimum conditions, the sensitive analysis method was established, and provided low limits of detection of 0.02 and 0.05 µg/L, good linearity ranges of 0.06-15 and 0.16-15 µg/L, as well as high enrichment factors of 176-1868. The method was applied to the online determination of trace polycyclic aromatic hydrocarbons in snow water and river water, and the relative recoveries corresponding to 2 and 5 µg/L were in the range of 80-116%. The repeatability of extraction and preparation of the device was investigated and the relative standard deviations (n = 3) were less than 3.6 and 5.2%.

Bare polyprolylene hollow fiber as extractive phase for in-tube solid-phase microextraction to determine estrogens in water samples.

Polypropylene hollow fibers as the adsorbent were directly filled into a polyetheretherketone tube for in-tube solid-phase microextraction. The surface properties of hollow fibers were characterized by a scanning electron microscope. Combined with high performance liquid chromatography, the extraction tube showed good extraction performance for five environmental estrogen hormones. To achieve high analytical sensitivity, four important factors containing sampling volume, sampling rate, content of organic solvent in sample, and desorption time were investigated. Under the optimum conditions, an online analysis method was established with wide linear range (0.03-20 µg/L), good correlation coefficients (≥0.9998), low limits of detection (0.01-0.05 µg/L), low limits of quantitation (0.03-0.16 µg/L), and high enrichment factors (1087-2738). Relative standard deviations (n = 3) for intraday (≤3.6%) and interday (≤5.1%) tests proved the stable extraction performance of the material. Durability and chemical stability of the extraction tube were also investigated, relative standard deviations of all analytes were less than 5.8% (n = 3), demonstrating the satisfactory stability. Finally, the method was successfully applied to detect estrogens in real samples.

An ionic-liquid-modified melamine-formaldehyde aerogel for in-tube solid-phase microextraction of estrogens followed by high performance liquid chromatography with diode array detection.

A combination between an ionic liquid and melamine-formaldehyde aerogel on the carbon fibers was developed for in-tube solid-phase microextraction of estrogens with high efficiency. The sorbent has a high enrichment capability for several estrogens. Scanning electron microscopy showed that the aerogel on the carbon fibers has a porous three-dimensional network structure. Several important parameters such as sampling volume, sampling rate, the concentration of organic solvent in sample, pH value of sample as well as desorption time were optimized towards estrogen targets. Comparing with melamine-formaldehyde aerogel coating, the coating gave higher extraction efficiency. Comparing with melamine-formaldehyde aerogel coating, the new coating displays higher extraction efficiency. An online analytical method of estrogens was established, by the combination between in-tube solid-phase microextraction and high performance liquid chromatography with diode array detector. Analytical figures of merit include low limits of detection (<0.20 µg L-1), wide linearity (0.15-20 µg L-1), high enrichment factors (1028-1256), good extraction repeatability (RSDs<2.5%) and satisfactory preparation repeatability (RSDs<10.5%). The method was applied to the determination of trace estrogen targets in plastic bottle, tap water and surface water. Graphical abstractSchematic representation of online combination between in-tube solid-phase microextraction and high performance liquid chromatography, based on an ionic liquid (IL)-modified melamine-formaldehyde (MF) aerogel coating on carbon fibers (CFs) in a polyether-etherketone (PEEK) tube.

Magnetic metal-organic framework composites for dual-column solid-phase microextraction combined with ICP-MS for speciation of trace levels of arsenic.

A dual column packed with a magnetic metal-organic framework composite (MFC) and mercapto-functionalized MFC nanoparticles (MFC-SH) in microfluidic chip channels is described for array chip-based magnetic solid phase microextraction of arsenic species including arsenite [As(III)], arsenate [As(V)], monomethylarsonous acid (MMA) and dimethylarsinic acid (DMA) in SCC-7 cells. At pH 6, the MFC-SH adsorbs As(III) while MFC quantitatively adsorbs As(V), DMA and MMA. The As(III) adsorbed on the MFC-SH can be desorbed with a 2% solution of thiourea in 0.5 M HNO3. The arsenic species MMA, DMA and As(V) are retained on the MFC but can be desorbed by ammonia. A sequential elution strategy was employed to elute MMA, DMA, As(V) and As(III) one by one for subsequent on-line determination by ICP-MS. The limits of detection are 4.8, 6.3, 3.8 and 7.1 ng L-1 for As(V), DMA, MMA and As(III), respectively. The enrichment factors are between 23 and 25, and the throughput is 7 samples per hour. The arsenic species in (spiked) SCC-7 cell samples were analyzed by the online system with adequate recoveries (89-110%). Graphical abstractSchematic representation of magnetic metal-organic framework composite (MFC) and mercapto-functionalized MFC nanoparticles (MFC-SH) packed dual-column, squamous carcinoma cells (SCC-7), online chip-based array MSPME-ICPMS system. Cell lysis units (blue), Microextraction units (black), Microvalves (green), Outlet (black), Permanent magnets (gray), Intet (red/purple/yellow).

Computer simulation of the enantioselective separation of weak bases in an online capillary electrophoresis based microanalysis configuration comprising sulfated cyclodextrin as selector.

Computer simulation was utilized to characterize the electrophoretic processes occurring after reactant mixing in an online assay format used for monitoring the enantioselective N-demethylation of ketamine to norketamine in the presence of highly sulfated γ-cyclodextrin (HS-γ-CD). The incubated reaction mixture (at pH 7.4 and without chiral selector) is bracketed by a low pH BGE containing 2% HS-γ-CD as chiral selector, thereby forming a discontinuous buffer system. Upon power application, simulation provides insight into the formation of moving boundaries and new zones together with the prediction of the behavior of ketamine and norketamine enantiomers. The analytes first migrate cationically in a zone electrophoretic manner until they come in contact with HS-γ-CD upon which enantioseparation is initiated. Complexation has a focusing effect and the electrophoretic transport becomes reversed, that is, toward the anode. Simulation revealed that the initial conditions for the chiral separation, including buffer components concentrations, pH, and ionic strength, are different than those in the BGE. As a consequence thereof, the experimentally determined complexation parameters for the BGE were unable to correctly describe the migration behavior of the analytes in this column section. An increase in the input binding constants by a factor of two to four, as a result of the decreased ionic strength, resulted in simulation data that agreed with experimental findings.