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The worldwide consumption of illicit drugs presents a big problem in terms of health care and prosecution. In the recent years, hundreds of novel psychoactive substances came up and were traded via the Internet, but there is still a big demand for classic illicit drugs such as cocaine, heroin, cannabis and ecstasy. Among these, cocaine particularly is frequently altered not only with excipients, but also with other physiologically active substances. The purpose of this work was to estimate the trend of cocaine purity and abundance of its adulterants in samples seized by Austrian police from 2012 to 2017. A micro-HPLC method for quantification of cocaine and its most common adulterants was developed and validated using gradient elution and UV detection at four wavelengths. 110 cocaine samples were analysed. In all the samples cocaine was present as hydrochloric salt. Caffeine, procaine, levamisole, phenacetin, lidocaine and benzocaine were the most abundant adulterants.

A highly sensitive and simple method for determining cryptotanshinone (Cry), tanshinone I (Tan I), and tanshinone IIA (Tan IIA) in Salvia miltiorrhiza was developed using micro HPLC with electrochemical detection (µHPLC-ED). The tanshinones were extracted using an ultrasonic method, with methanol as the extractant. The separation was carried out on a C18 (150 mm × 1.0 mm i.d., 3 µm particle size) analytical column. The mobile phase was acetonitrile-water-formic acid mixture (52:48:0.6, v/v/v) solution. The flow rate and the temperature of the column were set at 30 µL/min and 35°C. The applied potential was set at −0.4 V vs. Ag/AgCl. The peak heights for Cry, Tan I, and Tan IIA were found to be linearly related to the amounts injected, ranging from 0.145 µmol/L to 3.88 µmol/L, 0.226 µmol/L to 3.01 µmol/L, and 0.149 µmol/L to 3.98 µmol/L, respectively. The RSD values of intra-day precision and repeatability were not more than 3.0%, and the recovery of three analytes were ranged from 96.7% to 97.5%. The resu...

The purpose of this study is to improve the detection limit for trace herbicides, and to separate all samples within a short time with the combination of temperature and flow programming with micro‐reversed‐phase liquid chromatography (RPLC). The optimum condition for separation was ACN:0.05 M NaH2PO4 (46:54) (v/v), pH = 4.3, 40°C. The mass sensitivity is in the range between 0.086 × 10−13 g and 3.34 × 10−13 g in micro‐HPLC (HPLC). Micro‐HPLC exhibits higher mass sensitivity and better heat transfer than conventional HPLC. Thus, in the case of micro‐HPLC, the retention behavior of herbicides is easily determined according to the change of temperature. Especially, retention of triazines is decreased to a lesser extent with the increase of column temperature than that of other herbicides. This tendency has been accounted for the thermodynamic parameters ΔH° and ΔS°. The ΔS° for triazines is less negative than that for phenoxy acids, esters, and others. The chromatograms of herbicides were obtained ...

A new sampling procedure for individual raindrops with volumes of 4 nl - 4 μl is presented. It is demonstrated that analyte concentrations in small volumes can be analysed using micro-HPLC and capillary zone electrophoresis (CZE). Results for the analysis of cations such as Na+, NH4 +, K+, Mg2+, Ca2+, and anions such as Cl−, SO4 2-, NO3 −, NO2 − and organic acids are given and discussed.

The chromatographic performance of deuterated solvents, heavy water and deuteriobenzene, has been investigated in reversed phase and normal phase micro-HPLC. The performance of heavy water in separation was comparable or superior to that of light water in reversed phase mode. A slight improvement was also observed in catecholamines separation with heavy water. The performance of deuteriobenzene was observed as complicated in metal complexes separation, but a little difference was present. From those results, the combinations of micro HPLC and IR via flow-cell technique, proton-NMR, and ICP could be accomplished free from absorption or signals from mobile phase solvents.

A simple scheme was developed by utilization of a micro-HPLC technique in order to monitor synthetic reactions in-situ. The application of this system for the organic reaction of bromination of toluene was successfully presented.

The capcity factors determined by reversed-phase micro high performance liquid chromatography (micro-HPLC) can be used as one of the descriptors in Quantitative-Structure-Activity-Relationships (QSAR) studies. The present method gives a more simple and convenient way to study relationships between physicochemical properties and biological activities of some drugs.

The combination technique of micro high performance liquid chromatography and inductively coupled plasma atomic emission spectrometry is demonstrated in the separation of organometallic compounds. Problems relating to the interfacing between micro HPLC and ICP would be elininated uti1izing the simple interfacing technique.

The chromatographic potential of very short fused-silica column (30 mm length) packed with 3-μm particles has been investigated. The results indicate that this kind of micro-column has high applicability for a rapid identification of several samples. This technique also meets the recent demands in HPLC, as low solvent consumption and faster analysis time.