Development and validation of the spectrophotometric method of butaphosphan determination in veterinary preparations.

A simple and sensitive method has been developed for the determination of butaphosphan in single- and multi-component veterinary preparations. The method is based on the combustion of organic matter prior to the formation of phosphate and the subsequent formation of the phosphoric­molybdenum complex in the presence of molybdate and ascorbic acid as a reducing agent in the sulfate acid medium. The intensity of light absorption of the colored analytical form of "molybdenum blue" is measured at a wavelength of 830 nm in the range of 0.3-9.0 µg/ml of butaphosphan, where Beer's law is obeyed, has been measured. The reaction conditions and other experimental parameters influencing the reaction transition and the stability of the colored complex have been thoroughly investigated and optimized for the quantitative determination of butaphosphan. Validation of the developed method according to the requirements has been carried out State Pharmacopoeia of Ukraine garmonised with European Pharmacopoeia and its suitability for the analysis of the selected veterinary preparations for the quantitative content of butaphosfan has been confirmed. The results of the determination of butaphosphan in six veterinary preparations of domestic and imported products have been obtained with the help of the developed method. The received results are in agreement with the results obtained by the method of potentiometric titration.

Simultaneous determination of N-ethylpentylone, dopamine, 5-hydroxytryptamine and their metabolites in rat brain microdialysis by liquid chromatography tandem mass spectrometry.

N-Ethylpentylone (NEP) is a popular synthetic cathinone abused worldwide. To obtain more information about its pharmacokinetics and pharmacodynamics, a rapid, simple and sensitive liquid chromatography-tandem mass spectrometry method was developed for the determination of NEP, two important neurotransmitters, dopamine and serotonin, and their metabolites, including 3,4-dihydroxyphenylacetic acid, 3-methoxytyramine and 5-hydroxyindole-3-acetic acid, in rat brain microdialysate. The analytes were separated on a Phnomenex Polar C18 column, with a mobile phase of 0.1% formic acid in water (A) and 0.1% formic acid in acetonitrile (B) under gradient elution to shorten the total chromatographic run time. A triple quadruple mass spectrometer coupled with an electrospray ionization source in both positive and negative ion mode was used to detect the analytes. This method showed excellent accuracy (87.4-113.5%) and precision (relative standard deviation <15%) at three quality control levels. The limits of detection were 0.2 ng/mL for NEP and 0.2-50 nm for the others and good linearity was obtained. This study pioneered a method to integrate exogenous drugs and endogenous neurotransmitters as the drugs act on the same determination system, which means that this innovation can provide support for further study of the addictive effects of NEP or other synthetic cathinones on extracellular levels of dopamine and 5-hydroxytryptamine.

Control of the Intrinsic Sensor Response to Volatile Organic Compounds with Fringing Electric Fields.

The ability to control surface-analyte interaction allows tailoring chemical sensor sensitivity to specific target molecules. By adjusting the bias of the shallow p-n junctions in the electrostatically formed nanowire (EFN) chemical sensor, a multiple gate transistor with an exposed top dielectric layer allows tuning of the fringing electric field strength (from 0.5 × 107 to 2.5 × 107 V/m) above the EFN surface. Herein, we report that the magnitude and distribution of this fringing electric field correlate with the intrinsic sensor response to volatile organic compounds. The local variations of the surface electric field influence the analyte-surface interaction affecting the work function of the sensor surface, assessed by Kelvin probe force microscopy on the nanometer scale. We show that the sensitivity to fixed vapor analyte concentrations can be nullified and even reversed by varying the fringing field strength, and demonstrate selectivity between ethanol and n-butylamine at room temperature using a single transistor without any extrinsic chemical modification of the exposed SiO2 surface. The results imply an electric-field-controlled analyte reaction with a dielectric surface extremely compelling for sensitivity and selectivity enhancement in chemical sensors.

Simple quantification method for N-nitrosamines in atmospheric particulates based on facile pretreatment and GC-MS/MS.

Nine N-nitrosamines (i.e., N-nitrosomethylamine, N-nitrosodiethylamine (NDEA), N-nitrosodimethylamine (NDMA), N-nitrosodi-n-propylamine (NDPA), N-nitrosomorpholine (NMor), N-nitrosopyrrolidine (NPyr), N-nitrosopiperidine (NPip), N-nitorosodi-n-butylamine (NDBA), and N-nitrosodiphenylamine (NDPhA) in atmospheric PM2.5 collected in the fall season from an roadside site and a residential in Seoul, Korea have been analyzed using a newly developed method consisting of simple direct liquid extraction assisted by ultrasonication and subsequent quantification using a gas chromatography-triple quadrupole mass spectrometry (GC-TQMS). Excellent recovery values (92-100%) and method detection limits for the target compounds atmospheric PM samples could be achieved even without an evaporation step for sample concentration. The concentration of total N-nitrosamines in PM2.5 was ranged from 0.3 to 9.4 ng m-3 in this study; NDMA, NDEA, NDBA, NPyr, and NMor in PM2.5 were found to be the most frequently encountered compounds at the sampling sites. Since no industrial plant is located in Seoul, vehicle exhausts were considered major cause of the formation of nitrosamines in this study. The mechanisms how these compounds are formed and detected in the atmosphere are explained from the viewpoint of secondary organic aerosol. Considering the concentrations of N-nitrosamines and their associated potential health risks, a systematic monitoring of nitrosamines present in both ambient air and PM2.5 including seasonal and diurnal variations of selected sites (including potential precursor sources) should be carried out in the future. The proposed sample pretreatment method along with the analytical method will definitely help us perform the monitoring study.

The presence of aliphatic and aromatic amines in reservoir and canal water as precursors to disinfection by-products.

This research aimed at determining the dimethylamine (DMA), diethylamine (DEA), dibutylamine (DBA), and aromatic aniline (AN) in reservoir and canal water in the U-Tapao River Basin, Songkhla, Thailand. The trihalomethane formation potential (THMFP) and N-nitrosodimethylamine formation potential (NDMA-FP) of the reservoir and canal water were analyzed. Water samples from two reservoirs and raw water from water treatment plants at upstream, midstream, and downstream locations of the canal were collected twice. The analysis of the DMA, DEA, DBA, and AN were conducted using gas chromatography and spectrofluorometry techniques. The DMA, DEA, and DBA levels in the reservoir and canal waters ranged from not detectable (ND) to 10 µg/L and from ND to 21.2 µg/L, respectively. AN was detected from 123 to 129 ng/L and from 112 to 177 ng/L in the reservoir and canal waters, respectively. The DMA, DEA, DBA, and AN exhibited two fluorescent peaks at 230nmEx/345nmEm and 280 nmEx/355nmEm. These two peaks corresponded to the peak positions of tryptophan. Detection limits of DMA, DEA, and DBA for fluorescent analysis were 500 µg/L whereas that of AN and tryptophan were 10 and 0.5 µg/L, respectively. The NDMA-FP measured in all the water samples was lower than the detection limit of 237 ng/L. THMFP ranged from 175 to 248 µg/L and 214 to 429 µg/L was detected in the reservoir and canal waters, respectively. The THMFP/dissolved organic carbon (DOC) of the reservoir and canal waters were comparable within the ranges of 73 to 131 µg THMFP/mg DOC.

Detection of Acyl-CoA Derivatized with Butylamide for in vitro Fatty Acid Desaturase Assay.

Membrane-bound fatty acid desaturases acting on acyl-CoA contribute to the biosynthesis of unsaturated fatty acids, such as arachidonic acid and docosahexaenoic acid in higher organisms. We propose a simplified method for measuring the desaturase activity that combines the in vitro reaction by desaturase-expressing yeast cell homogenate and the detection of acyl-CoA product as butylamide derivatives by gas chromatography. To set up the in vitro reaction, we traced the in vivo activity of rat liver ∆6 fatty acid desaturase (D6d) expressed in the yeast, Saccharomyces cerevisiae, and determined the time taken for the D6d activity to reach its maximum level. The cell homogenate of yeast expressing the maximum D6d activity was made to react in vitro with linoleoyl-CoA to generate the D6d product, γlinolenoyl-CoA. This product was successfully detected as a peak corresponding to γ-linolenoyl butylamide on gas chromatography. This procedure, with low background expression, using non-labeled acyl-CoA as substrate, will contribute toward developing a simple in vitro desaturase assay. It will also help in elucidating the functions of membrane-bound fatty acid desaturases with various substrate specificities and regioselectivities.

Liquid chromatography-quadrupole time-of-flight mass spectrometry for screening in vitro drug metabolites in humans: investigation on seven phenethylamine-based designer drugs.

Phenethylamine-based designer drugs are prevalent within the new psychoactive substance market. Characterisation of their metabolites is important in order to identify suitable biomarkers which can be used for better monitoring their consumption. Careful design of in vitro metabolism experiments using subcellular liver fractions will assist in obtaining reliable outcomes for such purposes. The objective of this study was to stepwise investigate the in vitro human metabolism of seven phenethylamine-based designer drugs using individual families of enzymes. This included para-methoxyamphetamine, para-methoxymethamphetamine, 4-methylthioamphetamine, N-methyl-benzodioxolylbutanamine, benzodioxolylbutanamine, 5-(2-aminopropyl) benzofuran and 6-(2-aminopropyl) benzofuran. Identification and structural elucidation of the metabolites was performed using liquid chromatography-quadrupole-time-of-flight mass spectrometry. The targeted drugs were mainly metabolised by cytochrome P450 enzymes via O-dealkylation as the major pathway, followed by N-dealkylation, oxidation of unsubstituted C atoms and deamination (to a small extent). These drugs were largely free from Phase II metabolism. Only a limited number of metabolites were found which was consistent with the existing literature for other phenethylamine-based drugs. Also, the metabolism of most of the targeted drugs progressed at slow rate. The reproducibility of the identified metabolites was assessed through examining formation patterns using different incubation times, substrate and enzyme concentrations. Completion of the work has led to a set of metabolites which are representative for specific detection of these drugs in intoxicated individuals and also for meaningful evaluation of their use in communities by wastewater-based drug epidemiology.

Mobile phone based electrochemiluminescence detection in paper-based microfluidic sensors.

The development of simple, inexpensive paper-based sensors for medical diagnostics and other applications is now an important emerging area in the field of biosensors; however, the electronic instrument or reader used to interrogate such sensors adds significantly to the cost of the analysis. In this chapter we describe the design and construction of novel, low-cost disposable electrochemiluminescent (ECL) sensors based on screen printed carbon electrodes and paper-based microfluidics. Moreover, a method to interrogate these sensors using only a mobile phone is articulated. This is realized by exploiting the audio output of the device to achieve electrochemical control, while using the camera to detect the resulting light emitted during the ECL reaction. The combination of cell phone technology with low-cost paper microfluidic sensors dramatically reduces the cost of sensing and has the potential to enhance health-care outcomes by exploiting the functionality, connectivity, and close to worldwide penetration of mobile phone technology.

Simultaneous quantification of related substances of perindopril tert-butylamine using a novel stability indicating liquid chromatographic method.

A novel stability indicating gradient reverse-phased high-performance liquid chromatographic method has been developed for the quantification of impurities of perindopril tert-butylamine (PER) in pharmaceutical dosage form. Separation of the active substance and its known (Impurities B, C, D, E, F) and unknown impurities was achieved on a BDS Hypersil C18 column (250 mm × 4.6 mm, 5 µm), thermostated at 70°C, using a mobile phase comprised of aqueous solution of sodium 1-heptanesulfonate adjusted to pH 2 with perchloric acid and acetonitrile. The flow rate was maintained at 1.5 mL min(-1), injection volume of 20 µL was utilized and detection of analytes was performed at 215 nm. The developed method was validated in accordance with current ICH Guidelines for all suggested parameters, including forced degradation studies and proved to be linear, accurate, precise and suitable for the impurity testing of PER, being subsequently applied during on-going stability studies of a newly developed generic formulation.

Inhibition of monoamine oxidase (MAO) by α-ethylphenethylamine and N,α-diethylphenethylamine, two compounds related to dietary supplements.

Phenethylamines can interact with the metabolic enzyme monoamine oxidase (MAO), which can cause neurochemical dysfunction or changes in drug potency. A methamphetamine analog, N,α-diethylphenethylamine (N,α-DEPEA), was recently discovered in athletic performance-enhancing supplements, along with discovery of its metabolite, α-ethylphenethylamine (AEPEA). In vitro inhibition of human recombinant MAO by AEPEA and N,α-DEPEA was evaluated by measuring the fluorescence of 4-hydroxyquinoline produced from MAO substrate, kynuramine. AEPEA competitively inhibited human recombinant MAO A (Ki = 14.0 µM), which was 17-fold stronger compared to MAO B (Ki = 234 µM). Furthermore, N,α-DEPEA was a weak inhibitor of both MAO A (Ki = 251 µM) and MAO B (Ki = 159 µM). Trends regarding MAO A inhibition were explored among structural analogs, yielding the following ranking: amphetamine (Ki = 5.3 µM), AEPEA (Ki = 14.0 µM), methamphetamine (Ki = 17.2 µM), phentermine (Ki = 196 µM), and N,α-DEPEA (Ki = 251 µM). This study provides important data relating chemical structures and biochemical effects for two emerging compounds associated with dietary supplements.

A gated atmospheric pressure drift tube ion mobility spectrometer-time-of-flight mass spectrometer.

Identifying the compounds of an unknown gas mixture by using an ion mobility spectrometer (IMS) is a difficult task, because several ion species can be generated in the ionization process. One method to analyze the occurring peaks in an IMS spectrum is coupling an IMS to a mass spectrometer (MS). In our setup we coupled a (3)H drift tube IMS to a Bruker micrOTOF II. Therefore, the detector plate of the IMS is pierced and a transfer capillary is inserted. The ions are transferred via gas flow and electric fields into the MS. The transmission of the ions through the transfer capillary can be shuttered very precisely by increasing the electric potential of the detector generating a repulsive electric field. Thus, it is possible to transfer single ion clouds of generated IMS spectra into the mass spectrometer where a corresponding mass spectrum is generated. In this work we analyze the positive and negative IMS spectra of single analytes as well as gas mixtures and characterize the occurring ion species.

LC-MS-MS analysis of dietary supplements for N-ethyl-α-ethyl-phenethylamine (ETH), N, N-diethylphenethylamine and phenethylamine.

There has been a recent rise in the number of cases of athletes being banned from competition because of positive tests for prohibited substances in their biological specimens. Most of these substances are on the World Anti-Doping Agency (WADA) prohibited list, while others are not specifically named on the list. N-Ethyl-α-ethyl-phenethylamine (ETH), a derivative of phenethylamine (PEA), is one of these unlisted substances and shares chemical and biological effects to the amphetamines, which are listed on the WADA prohibited substances list. It is classified as Category 6B stimulant on the list. This study was directed toward the development of an liquid chromatography tandem mass spectrometry (LC-MS-MS) method for the analysis of ETH in performance-enhancing dietary supplement. A standard was prepared and confirmed by spectroscopic analysis, which was then used to develop the analytical procedure. The procedure was validated and found to have an limit of detection of 2.5 ng/mL, limit of quantification of 5 ng/mL and upper limit of linearity of 500 ng/mL, with within-day variability at the 10-ng/mL level range of 3.88-7.89% (n = 6) and 1.39-3.36% (n = 6) for the 100-ng/mL level. The day-to-day variability was 9.8% for the low control and 3.1% for the high control. The method was used to analyze a variety of dietary supplements for ETH as well as PEA and its N, N-diethyl derivative (NDP).

Medical management of a potentially toxic accidental trialkylamine ingestion during spaceflight.

INTRODUCTION: To reduce excessive iodine consumption by astronauts, the National Aeronautics and Space Administration (NASA) has developed various methods of removing residual iodine after iodine-based water purification aboard spacecraft. The Low Iodine Residual System (LIRS) was developed as an iodine removal system for use aboard the space shuttle. This is a case report of an accidental, potentially toxic ingestion by astronauts aboard a space shuttle mission following exposure to contaminated water from LIRS filtration and the medical response operations that followed. CASE REPORT: Astronauts ingested significant levels of trialkylamines from water that had passed through gamma-irradiated, de-iodination resin in the LIRS hardware. Medical response operations included crew evaluations, consultations with toxicologists and systems experts, hardware testing, contaminant evaluation, and close crewmember follow-up. DISCUSSION: Despite the significant ingestion there were no adverse clinical symptoms in any of the exposed astronauts; however, the case highlights a simple pitfall in the classification of hardware that ultimately lead to a potentially harmful toxic ingestion among the crewmembers, and the real-time response of medical personnel to ensure crew safety.

Flexible shrink-induced high surface area electrodes for electrochemiluminescent sensing.

Photolithographically defined metallic thin film on commodity shrink-wrap is leveraged to create robust electrodes. By thermally shrinking the film, electrodes are reduced by 20× in footprint for improved resolution and conductivity with >600% enhancements in electrochemically active surface area; as electrochemiluminescent sensors, they demonstrate improved limits of detection.

An electrochemiluminescence sensor based on a Ru(bpy)3(2+)-silica-chitosan/nanogold composite film.

Chitosan, a cationic polysaccharide containing amino and hydroxyl groups, was used to fabricate an electrochemiluminescence (ECL) sensor. In the sensor construction, a glassy carbon electrode (GCE) was first coated by a chitosan film which embedded gold nanoparticles, and then the film was modified by introducing carboxyl groups on the surface, which were used to immobilize tris(2,2'-bipyridyl)ruthenium(II) doped amino-functional silica nanoparticles (NH(2)-RuSiNPs) through amido links. The successful modification was confirmed by scanning electronic microscopy and cyclic voltammetry. A binding model between the chitosan/nanogold composite film and NH(2)-RuSiNPs was also proposed, in which the amido link was the dominant bonding, accompanied with hydrogen bond interaction. ECL studies revealed that the sensor had very good response to different concentrations of 2-(dibutylamino) ethanol. This sensor was also applied in methamphetamine determination.

Multi-channel purge and trap system coupled with ion chromatography for the determination of alkylamines in cosmetics.

A new multi-channel purge and trap system coupled with ion chromatography for the determination of six alkylamines in cosmetics was developed. The proposed method, based on purge and trap of the volatile alkylamines, involved in a miniaturization and multi-channel integration of classical steam distillation and a simple approach for routine labs. The procedure was rapidly achieved within 10 min and the matrix interferences could be effectively eliminated. Sample pretreatment frequency was higher than 40 h(-1). The linear ranges were 0.1-15 mg L(-1) and the detection limits varied from 0.023 to 0.038 mg L(-1). This method was successfully utilized to determine the amounts of alkylamines in cosmetics with recoveries ranging from 80.3 to 105.5% and the relative standard deviations (RSDs) ranging from 0.78 to 7.5%. It was proved to be accurate, time-saving, and suitable for the determination of large numbers of cosmetics in a short time.

Ionization mechanism of the ambient pressure pyroelectric ion source (APPIS) and its applications to chemical nerve agent detection.

We present studies of the ionization mechanism operative in the ambient pressure pyroelectric ionization source (APPIS), along with applications that include detection of simulants for chemical nerve agents. It is found that ionization by APPIS occurs in the gas-phase. As the crystal is thermally cycled over a narrow temperature range, electrical discharges near the surface of the crystal produce energetic species which, through reactions with atmospheric molecules, result in reactant ions such as protonated water clusters or clusters of hydroxide and water. Reactant ions can be observed directly in the mass spectrometer. These go on to react with trace neutrals via proton transfer reactions to produce the ions observed in mass spectra, which are usually singly protonated or deprotonated species. Further implicating gas-phase ionization, observed product distributions are highly dependent on the composition of ambient gases, especially the concentration of water vapor and oxygen surrounding the source. For example, basic species such as triethylamine are observed as singly protonated cations at a water partial pressure of 10 torr. At a water pressure of 4 torr, reactive oxygen species are formed and lead to observation of protonated amine oxides. The ability of the APPIS source to detect basic molecules with high proton affinities makes it highly suited for the detection of chemical nerve agents. We demonstrate this application using simulants corresponding to VX and GA (Tabun). With the present source configuration pyridine is detected readily at a concentration of 4 ppm, indicating ultimate sensitivity in the high ppb range.

Liquid chromatography quadrupole time-of-flight mass spectrometry analysis of carbosulfan, carbofuran, 3-hydroxycarbofuran, and other metabolites in food.

The potential of liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QqTOF-MS) to identify and confirm carbosulfan and seven of its main metabolites (carbofuran, 3-hydroxycarbofuran, 3-ketocarbofuran, 3-hydroxy-7-phenol carbofuran, 3-keto-7-phenolcarbofuran, 7-phenolcarbofuran, dibutylamine) at trace levels from food is explored for the first time. The analytical method developed consists of pressurized liquid extraction (PLE) and LC-QqTOF-MS in positive ion mode, which attains unequivocal identification and quantification of the studied compounds in food, at levels well below of those of concern (0.05 mg/kg for the sum of carbosulfan, carbofuran, and 3-hydroxycarbofuran). PLE recoveries ranged from 55 to 94% with limits of quantification from 10 (for carbosulfan, carbofuran, 3-hydroxycarbofuran, and dibutylamine) to 70 microg/kg (3-keto-7-phenolcarbofuran). The method is precise, with relative standard deviations varying between 5 and 11% for the repeatability (within-day) and 8-13% for the reproducibility (interday). This method was used to monitor the presence and fate of the target compounds in orange, potato, and rice crops treated with a commercial product containing carbosulfan. Field degradation studies show that carbofuran, 3-hydroxycarbofuran, and dibutylamine are the main degradation products formed in the environmental disappearance of carbosulfan.

Comparison of four mass analyzers for determining carbosulfan and its metabolites in citrus by liquid chromatography/mass spectrometry.

Four liquid chromatography/mass spectrometry (LC/MS) systems, equipped with single quadrupole, triple quadrupole (QqQ), quadrupole ion trap (QIT) and quadrupole time-of-flight (QqTOF) mass analyzers, were evaluated for the analysis of carbosulfan and its main transformation products. The comparison of quantitative aspects (sensitivity, precision and accuracy) was emphasized. Results showed that the triple quadrupole instrument reaches at least 20-fold higher sensitivity (LOD from 0.04 to 0.4 microg kg(-1)) compared to the single quadrupole (4-70 microg kg(-1)), the QIT (4-25 microg kg(-1)) and the QqTOF (4-23 microg kg(-1)) instruments. Recoveries were over 70% for all the analytes, except dibutylamine and 7-phenolcarbofuran. Repeatabilities (within-day) were slightly better by the single quadrupole (5-10%) and the QqQ (5-9%) than by the QIT (12-16%) and the QqTOF (9-16%). Both the QqTOF and QIT offer a linear dynamic range of two orders of magnitude whereas the single quadrupole and QqQ of, at least, three orders of magnitude. The method was applied to analyze carbosulfan field-treated orange samples, in which carbosulfan, carbofuran, 3-hydroxycarbofuran, and dibutylamine were found. As an example, the mean carbosulfan concentration was 20 +/- 0.6 microg kg(-1) measured by the QqQ, 22 +/- 1.2 microg kg(-1) by the single quadrupole, 25 +/- 2.8 microg kg(-1) by the QIT, and 20 +/- 1.8 microg kg(-1) by the QqTOF. Although the QqQ is more sensitive and precise, the mean values obtained by the four instruments are acceptable and comparable. The potential of each technique for the verification of the identity of residues detected in oranges is discussed using the concept of identification points.

Determination of tertiary amines based on pH junctions and field amplification in capillary electrophoresis with electrochemiluminescence detection.

A stacking approach based on pH junction and field amplification has been developed for determining amines by capillary electrophoresis (CE) with electrochemiluminescence (ECL) detection. A two-electrode configuration was employed with an indium/tin oxide-coated glass as a working electrode and a platinum wire as a pseudoreference electrode. The ECL system also contains a flow cell (poly(dimethylsiloxane)-aluminum oxide) that was made from a mixture of Sylgard 184 silicone elastomer, a curing agent, and aluminum oxide. In order to improve the sensitivity of the present CE-ECL system using tris(2,2'-bipyridyl) ruthenium(II) (Ru(bpy)(3) (2+)), a stacking approach based on pH junctions and field amplification has been tested for the analysis of triethylamine (TEA), tripropylamine (TPA), and tributylamine (TBA). Once amines (cations) prepared in citric acid solution (pH < 4.0) migrate towards the background electrolyte (15 mM sodium borate at pH 8.0), they slow down and are stacked at the boundary as a result of deprotonation and decreases in the electric field. By applying hydrodynamic injection of the sample for 60 s, this method provides the concentration limits of detection (signal-to-noise ratio = 3) of 24, 20, and 32 nM for TEA, TPA, and TBA, respectively. The results indicate that the stacking CE-ECL system is better than CE-ECL systems using a two-electrode configuration and comparable to those using a three-electrode configuration. The potential applicability of the new and low-cost CE-ECL system has been demonstrated by the determination of 1.0 microM lidocaine, a local anesthetic drug, in urine without any tedious sample preparation.