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We report the results of experimental work focusing on host-guest supramolecular complex creation between macrocyclic compound (β-cyclodextrin) and 1-acenaphthenol enantiomers (racemic mixture) in liquid phase composed of 35% acetonitrile in water (v/v) at different temperatures ranging from 0 to 90 °C. Experimental setup involved several analytical protocols based on classical non-forced flow planar chromatography (RP-18 TLC plates), micro-TLC (RP-18 W HPTLC plates), column chromatography (HPLC with C-18 and C-30 stationary phases), as well as UV-Vis spectrophotometry and optical microscopy. It has been found that under various planar chromatographic conditions (stationary plates type, chamber shape and volume, development mode, and saturation) non-typical retention properties (extremely high retention) of 1-acenaphthenol at subambient temperatures can be observed. To our knowledge, reported experimental results are in opposition to currently described retention models based on column chromatographic investigation of host-guest complexes (where in case of strong interaction of given analyte with macrocyclic mobile phases additive, which itself is non strongly retarded by stationary phase-close to the retention of dead volume marker, the retention of target compounds is shortened at low temperatures). To explain this TLC phenomenon that may have in our opinion a number of practical applications, especially for selective high throughput separation involving microchromatographic and/or microfluidic devices as well fractionation and extraction protocols (using, e.g., bar extraction systems), several experiments were conducted focusing on (i) acenaphthenol chromatography under different instrumental conditions, (ii) cyclodextrin retention measured as analyte or mobile phase additive, (iii) plate development time under different mobile phases and temperature settings, (iv) various column chromatographic conditions including C-30 and two C-18 stationary phases, (v) UV-Vis spectrophotometry, and (vi) microscopy inspection of precipitated CD-acenaphthenol crystals. Analysis of collected data has revealed that the most probable reasons for TLC retention behavior of 1-acenaphthenol under β-cyclodextrin additive conditions can be associated with (i) solubility changes of created host-guest complex, (ii) kinetics of solid complex precipitation, and (iii) differences in analysis time between planar and column chromatography. Because precipitation phenomenon may have a massive impact on analytes quantification involving macrocycles as the mobile phase additives, our previously reported data concerning a number of low-molecular compounds (mainly steroids and non steroidal endocrine disrupting chemicals) using HPLC methodology based on binary mobile phases without and with β-cyclodextrin and its hydroxypropyl derivative were re-examined and results discussed. Considering these data and the whole data set reported presently, the enhanced model of chromatographic retention driven by host-guest interaction was proposed.

A novel miniaturized sample extraction capillary was developed to provide a simple and sensitive method for analyzing gaseous formaldehyde (FA) using conventional high-performance liquid chromatography (HPLC). The extraction capillary was prepared by packing silica gel particles in a stainless steel capillary with a 1.6-mm o.d. Before the gaseous samples were collected, the silica gel particles were impregnated with a derivatizing reagent 2,4-dinitrophenylhydrazine (DNPH) by passing a solution of DNPH through the extraction capillary. FA was derivatized to form the corresponding hydrazone during the active sampling of a gaseous sample, and the derivative was sorbed by the silica gel. The capillary was then directly connected to a six-port valve, and desorption from the capillary and injection into the HPLC were achieved simultaneously by passing a solvent through the capillary. The run-to-run and device-to-device variabilities, as relative standard deviations, were both less than 6.9%. The limit of detection for FA was 2.5 ng/L using a sampling volume of 100 mL, and a sample collection time of 2 min. Acetaldehyde and acetone in a gaseous sample could also be simultaneously extracted and determined using this method. The applicability of the developed method for determining FA in real indoor air samples was confirmed by comparing the results obtained using the proposed method and a conventional sample preparation method. The developed method enables the rapid and simple sample preparation of gaseous FA and gives a good level of sensitivity.

Purpose: To evaluate the ocular circulation in diabetic patients with coronary artery disease (CAD)., Methods: Thirty diabetic patients with diabetic retinopathy of grade 20 or 35, as evaluated by the Early Treatment Diabetic Retinopathy Study, were studied. They were divided into those without CAD (15 cases) and those with CAD (over 75% stenosis of carotid artery; 15 cases). All underwent standard ophthalmic examinations and orbital color Doppler imaging. Fifteen healthy controls underwent the same examinations., Results: The peak systolic velocity in the central retinal artery was significantly lower in the two diabetic groups. The end-diastolic velocity in the central retinal artery was significantly lower only in the diabetic patients with CAD. There were no significant intergroup differences in blood flow velocities in the ophthalmic artery, short posterior ciliary artery, and central retinal vein. The blood flow waves were flattened in the diastolic phase for all orbital arteries in significantly more eyes in the diabetic patients with CAD. Echocardiography, performed only in the diabetic patients with CAD, showed that 10 cases (67%) had reduced systolic functions and/or diastolic functions and/or asynergy of the left ventricle., Conclusions: A decrease in blood flow velocities in the diastolic phase was found in diabetic patients with CAD. The findings indicate that this is probably related to the decrease in cardiac output.

Phosphate is generally analyzed by color intensity of phosphoantimonylmolybdenum blue (PAMB): especially by a spot test based on spectrophotometric or visual determination. Visual determination is one of the simplest and most inexpensive methods; however, it is believed to be of low precision. In this work, we have developed an alternative phosphate spot test, where phosphate concentration is measured by the color band length of PAMB formed in a detection tube similar to a gas detection tube. The color band is formed by the entrapment of the hydrophobic ion pair of PAMB and quaternary ammonium ions in the column; we demonstrated that this color band length correlates quantitatively with the phosphate concentration. In order to optimize the measurement performance, systematic investigations have been carried out for various experimental parameters such as phosphate concentration, preparation conditions of the column packing material, the type of support material (either silica-gel or PVC), the solution feeding conditions (filtration or penetration), and volume of the sample solution. The effects from some co-existing components were also studied for the measurement of real samples. Determination of phosphate concentrations in actual wastewaters was successfully carried out by this method, indicating that the quantification range achievable was of 3-18 mg PO(4) L(-1) without dilution prior to the analysis. No interference was observed from suspended solid (SS) and organic pollutants (COD, TOC) during the wastewater analysis. Because of the simplicity and rapid processing of the samples (not requiring any special instruments) this newly developed method can be applied to the on-site analysis of wastewater.