超高效液相色谱-串联质谱法测定阿胶中的驴皮源成分

近年来由于驴皮资源短缺,阿胶价格大幅度上涨,市场上出现了大量以马、骡、猪、牛皮等熬制而成的假胶,导致阿胶质量的参差不齐,严重扰乱了市场,急需高效准确的检测方法提升阿胶品质.该研究采用超高效液相色谱-串联质谱技术,建立了阿胶中驴皮源成分的检测方法.样品加水溶解后,于37℃下经胰蛋白酶酶解,产生驴源性特征肽段,以0.1％甲...     

Determination of paeoniflorin, ferulic acid and baicalin in the traditional Chinese medicinal preparation Dang-Guei-San by high-performance liquid chromatography

A high-performance liquid chromatographic method for the determination of paeoniflorin, ferulic acid and baicalin in the traditional Chinese medicinal preparation Dang-Guei-San, which contains Paeoniae Radix, Swertiae Herba, Cnidii Rhizoma and Scutellariae Radix, was established. The samples were separated with a Cosmosil 5C₁₈-AR column by gradient elution with 0.03% (v/v) phosphoric acid- acetonitrile (0 min 96:4, 5 min 84:16, 7 min 82:18, 14–30 min 78:22) as the mobile phase at a flow-rate of 1.0 ml/min, with detection at 245 nm. Methylparaben was used as the internal standard and three equations were derived showing linear relationships between the peak- area ratios of marker components (paeoniflorin, ferulic acid and baicalin) to methylparaben and concentration. The recoveries of paeoniflorin, ferulic acid and baicalin were 27.86, 33.89 and 49.31%, respectively. The repeatability (relative standard deviation) was generally less than 5% (n = 5). The effects of various processes such as concentration by reduced-pressure evaporation, freeze-drying and spray-drying were studied and commercial concentrated herbal preparations containing Paeoniae Radix, Swertiae Herba, Cnidii Rhizoma and Scutellariae Radix were also analysed.     

Comparative methodology in the determination of alpha-oxocarboxylates in aqueous solution ion chromatography versus gas chromatography after oximation, extraction and esterification

A direct, simple and rapid high-performance liquid chromatographic method has been developed for the determination of ketoprofen with ibuprofen as internal standard. Samples were chromatographed on a 5 μm Kromasil 100 C₁₈ column. The mobile phase was a mixture of acetonitrile–0.01 M KH₂PO₄ adjusted to pH 1.5 with orthophosphoric acid 85% (60:40, v/v). Detection was at 260 nm and the run time was 10 min. The detector response was found to be linear in the concentration range 0.02 to 40 μg/ml. This HPLC assay has been applied to measure the “in vitro” percutaneous penetration of ketoprofen through rat skin.     

Determination of cilnidipine, a new calcium antagonist, in human plasma using high performance liquid chromatography with tandem mass spectrometric detection

A rapid, sensitive and reliable high performance liquid chromatographic method coupled with tandem mass spectrometry (HPLC–MS/MS) has been developed and validated for the determination of cilnidipine, a relatively new calcium antagonist, in human plasma. The reversed-phase chromatographic system was interfaced with a TurboIonSpray (TIS) source. Nimodipine was employed as the internal standard (IS). Sample extracts following protein precipitation were injected into the HPLC–MS/MS system. The analyte and IS were eluted isocratically on a C18 column, with a mobile phase consisting of CH₃OH and NH₄Ac (96:4, v/v). The ions were detected by a triple quadrupole mass spectrometric detector in the negative mode. Quantification was performed using multiple reaction monitoring (MRM) of the transitions m/z 491.2 → 122.1 and m/z 417.1 → 122.1 for cilnidipine and for the IS, respectively. The analysis time for each run was 3.0 min. The calibration curve fitted well over the concentration range of 0.1–10 ng mL⁻¹, with the regression equation Y = (0.103 ± 0.002)X + (0.014 ± 0.003) (n = 5), r = 0.9994. The intra-day and inter-day R.S.D.% were less than 12.51% at all concentration levels within the calibration range. The recoveries were between 92.71% and 97.64%. The long-term stability and freeze-thaw stability were satisfying at each level. The present method provides a modern, rapid and robust tool for pharmacokinetic studies of cilnidipine.     

Determination of As, Cd, Pb and Se in DORM-1 dogfish muscle reference material using alkaline solubilization and electrothermal atomic absorption spectrometry with Ir+Rh as permanent modifiers or Pd+Mg in solution

In this work, tetramethylammonium hydroxide (TMAH) was used to solubilize the DORM-1 dogfish muscle certified reference material as a model substance for the determination of As, Cd, Pb and Se by electrothermal atomic absorption spectrometry (ET AAS). The sample was mixed with a small amount of TMAH and heated to 60 °C for 10 min in a water bath. After dissolution, As and Se were determined using palladium and magnesium nitrates as a chemical modifier added in solution. For Cd and Pb, best results were obtained with a mixture of 250 μg of each of iridium and rhodium as permanent modifiers. In both cases, the calibration was performed with aqueous solutions in 0.2% v/v HNO₃. The temperature program for each analyte was optimized using pyrolysis and atomization curves established with the fish reference material. The detection limits in dry samples and the characteristic mass values were: Cd 0.005 μg g⁻¹ and 0.9 pg; Pb 0.04 μg g⁻¹ and 7.6 pg; As 0.4 μg g⁻¹ and 13 pg and Se 0.6 μg g⁻¹ and 20 pg, respectively. Results from the determination of these elements in the DORM-1 certified fish reference material were within the 95% confidence interval of the certified values.     

Reversed-phase HPLC method for the estimation of acetaminophen, ibuprofen and chlorzoxazone in formulations

A simple, precise and rapid reversed-phase HPLC method was developed for the simultaneous estimation of acetaminophen, ibuprofen and chlorzoxazone in formulations. The method was carried out on a Kromasil® C₈ column using a mixture of 0.2% triethylamine:acetonitrile (adjusted to pH 3.2 using dilute orthophosphoric acid), and detection was carried out at 215 nm using ketoprofen as internal standard. All these drugs showed linearity in the range of 2–10 μg ml⁻¹, and limits of quantification was found to be 10, 50 and 20 ng ml⁻¹ for acetaminophen, ibuprofen and chlorzoxazone, respectively.     

Determination of vitamin B12 in multivitamin tablets by multimode high-performance liquid chromatography

Quantitative determination of vitamin B₁₂ in B-complex tablets was performed by using multimode high-performance liquid chromatography. The multivitamin tablets (B₁, B₆ and B₁₂) were sonicated for 30 min in methanol–water (50:50, v/v) and diluted to appropriated volume with the same solvent. The resulting solution was filtered and the filtrate was analysed on a phenylpropanolamine bonded silica column (15 cm×4.6 mm I.D., 5 μm). The optimized mobile phase was 30 mM phosphate buffer (pH 3.00) containing 6% (v/v) acetonitrile at a flow-rate of 1 ml min⁻¹ and the detection was measured at 361 nm. The calibration graph prepared using standards was linear from 0.05 to 0.25 μg. The determination limit was 25 ng, the relative standard deviation was 0.47% and recovery from tablet solution was 100%. An analysis was completed in 5 min. The new method is simple, rapid and precise.     

Reverse flow injection spectrophotometric determination of iron(III) using norfloxacin

A reversed flow injection colorimetric procedure for determining iron(III) at the μg level was proposed. It is based on the reaction between iron(III) with norfloxacin (NRF) in 0.07 mol l⁻¹ ammonium sulfate solution, resulting in an intense yellow complex with a suitable absorption at 435 nm. Optimum conditions for determining iron(III) were investigated by univariate method. The method involved injection of a 150 μl of 0.04% w/v colorimetric reagent solution into a merged streams of sample and/or standard solution containing iron(III) and 0.07 mol l⁻¹ ammonium sulfate in sulfuric acid (pH 3.5) solution which was then passed through a single bead string reactor. Subsequently the absorbance as peak height was monitored at 435 nm. Beer's law obeyed over the range of 0.2–1.4 μg ml⁻¹ iron(III). The method has been applied to the determination of total iron in water samples digested with HNO₃–H₂O₂ (1:9 v/v). Detection limit (3σ) was 0.01 μg ml⁻¹ the sample through of 86 h⁻¹ and the coefficient of variation of 1.77% (n=12) for 1 μg ml⁻¹ Fe(III) were achieved with the recovery of the spiked Fe(III) of 92.6–99.8%.     

A liquid chromatographic method, with fluorometric detection, for the determination of enrofloxacin and ciprofloxacin in plasma and endometrial tissue of mares

The aim of this work was to develop and validate a simple and sensitive analytical method for determining enrofloxacin (EFX) and ciprofloxacin (CFX) in equine plasma and endometrial tissue samples, as a precursor to conducting pharmacokinetic/pharmacodynamic studies on equine endometritis This was achieved in the form of a liquid chromatographic procedure, with fluorometric detection, which also gave good separation of other fluoroquinolones including marbofloxacin (MFX), danofloxacin (DFX) and ofloxacin (OFX). Analytes were separated on a C₁₈ reversed phase column using an acidified mobile phase. The exact composition of the mobile phase differed for plasma (16% acetonitrile:methanol [13:1,v/v] 84% water containing 0.4% triethylamine and 0.4% phosphoric acid [35%]) and endometrial tissue (14% acetonitrile, 86% water, without methanol) samples. EFX and CFX were both detected at excitation and emission wavelengths of 294 and 500 nm, respectively. Prior to chromatography, EFX and CFX were purified by solid phase extraction from plasma, and a combination of solvent/solid phase extraction from endometrial tissue.

Mean absolute recoveries for EFX and CFX from plasma were 94.1 and 78.0%, respectively, and from endometrial tissue, 78.0 and 57.8%, respectively, with a percentage residual standard deviation (%R.S.D.) <10% in each case. Mean relative recoveries for EFX and CFX from plasma were 91.3 and 119.4%, respectively, and from endometrial tissue, 80.2 and 108.0%, respectively, with a %R.S.D. <20% in each case.

Standard curves constructed using blank plasma and endometrial tissue samples, spiked with authentic EFX and CFX in the ranges 0.005–10.0 μg mL⁻¹ and 0.05–10.0 μg g⁻¹, respectively, all showed acceptable linearity with correlation coefficients, r² ≥ 0.977. Mean intra- and inter-day precision (expressed as %R.S.D.) was <6 and <13%, respectively, with an associated accuracy (expressed as percentage relative error, %R.E.) of <20% for both analytes in both matrices. Acceptable precision and accuracy was also demonstrated at the pre-assigned LOQs of 0.005 μg mL⁻¹ for both EFX and CFX in plasma, and 0.05 μg g⁻¹ for both drugs in endometrial tissue. EFX and CFX were stable in both plasma and endometrial tissue for at least 60 days at −20 °C.     

Determination of fenpyroximate in apples by supercritical fluid extraction and packed capillary liquid chromatography with UV detection

A method using off-line supercritical fluid extraction (SFE) and micro liquid chromatography (μLC) with UV detection at 260 nm, was developed for selective determination of fenpyroximate in apple samples. The packed capillary liquid chromatography method utilises 20 μl injection volumes with on-column focusing. A 350×0.32 mm capillary column packed with Kromasil 100-C₁₈ of 5 μm particle size was used with a mobile phase of acetonitrile–10 mM ammonium acetate (85:15, v/v) at a flow of 5 μl/min. A two-step SFE procedure was used to extract fenpyroximate selectively in 2 g apple samples, with Hydromatrix (HMX) added as a water absorbent at a 1:1 (w:w) ratio. Fenpyroximate was extracted at 200 bar and 90°C for 15 min using carbon dioxide at a flow of 2 ml/min, and solvent trapping collection in 10 ml acetonitrile. The volume of the acetonitrile extract was reduced by evaporation and water was added to a final composition of acetonitrile–water (40:60, v/v). The resulting 2.0 ml solution was filtered using a 0.45 μm poly(vinylidene difluoride) syringe filter before μLC analysis. Validation of the method was accomplished with apple samples spiked with fenpyroximate, covering the range of 0.1 to 1.0 μg/kg. The within-day and between-day repeatabilities were in the range 4–18% relative standard deviation. Accuracy, measured as recovery, was found to be approximately 60%. Apple samples from a field treated with fenpyroximate were analysed. None of the samples contained fenpyroximate above the quantification level.     

Determination of mangiferin, jateorrhizine, palmatine, berberine, cinnamic acid, and cinnamaldehyde in the traditional Chinese medicinal preparation Zi-Shen pill by high-performance liquid chromatography

High-performance liquid chromatography is employed to determine the contents of six marker components such as mangiferin, jateorrhizine, palmatine, berberine, cinnamic acid, and cinnamaldehyde in the traditional Chinese medicinal preparation Zi-Shen pill. The separation is performed on a C(18) column by stepwise gradient elution with water (0.2%, v/v, triethylamine adjusted to pH 4 with phosphoric acid)-methanol-acetonitrile (0.01 min, 98:0:2; 20 min, 80:5:15; 30 min, 65:13:22; and 55 min, 65:13:22) as the mobile phase at a flow rate of 0.9 mL/min, with UV detection at 280 nm. Six regression equations show good linear relationships between the peak area of each marker and concentration. The recoveries of the markers listed are 95.5%, 98.3%, 96.8%, 99.5%, 101.7%, and 102.1%, respectively. The repeatability and reproducibility (relative standard deviation) of the method are less than 2.5% and 3.3%, respectively.     

On-line sample treatment and FT-IR determination of doxylamine succinate in pharmaceuticals

A low solvent consumption method for Fourier transform infrared spectroscopy (FT-IR) determination of doxylamine succinate in pharmaceuticals has been developed. The analyte was continuous and selectively extracted with a 13% (v/v) ethanol:chloroform solvent mixture, recirculating the solvent through the sample and monitoring the process by FT-IR. Doxylamine succinate was determined by on-line standard addition measuring the peak area in the regions 1730–1710 and 1485–1462 cm⁻¹ corrected with a two-point baseline established between 2000 and 1800 cm⁻¹. This new method implies low volumes of chloroformic solvent mixture, only 2.6 mL per sample, in front of classical batch FT-IR methods, improving analytical efficiency and reducing waste generation. The on-line extraction and standard addition determination of doxylamine succinate allowed a throughput of 10 h⁻¹.     

An on-line flow-injection microwave-assisted mineralization and a precipitation/dissolution system for the determination of molybdenum in blood serum and whole blood by electrothermal atomic absorption spectrometry

An on-line flow injection (FI) precipitation–dissolution system with microwave-assisted sample digestion has been developed for the electrothermal atomic absorption spectrometry (ETAAS) determination of trace or ultratrace amounts of molybdenum in human blood serum and whole blood samples. After the exposure of the sample to microwave radiation, the on-line precipitation of molybdenum was achieved by the merging-zone of a 0.5-ml plug of sample with a plug of potassium ferrocyanide, which were carried downstream with a solution of 0.5 mol l⁻¹ of HNO₃. The interfering effects of iron and copper were minimized by the introduction of a flow of a 5% (w/v) sodium potassium tartrate (for iron) and 2% (w/v) of thiourea (for copper and zinc) in a 5% (v/v) ammonia and 2% (v/v) ammonium chloride solution previous to the precipitation reaction. The reddish-brown precipitate of molybdenyl ferrocyanide was collected on the walls of a knotted reactor. The precipitate was dissolved with the introduction of 1 ml of a 3.0 mol l⁻¹ NaOH solution and the best performance in terms of detection limit and precision was achieved when a sub-sample of 140 μl was collected in a capillary of a sampling arm assembly, to introduce 20 μl volumes into the atomizer by means of positive displacement with air through a time-based injector. A detection limit (3σ) of 0.1 μg Mo l⁻¹ using an aqueous standard solution was obtained. The method is quantitative and is applied over the range 0.2–20.0 μg Mo l⁻¹. The precision of the method evaluated by ten replicate analyses of aqueous standard solutions containing 0.5 and 1.0 μg Mo l⁻¹ was 2.8 and 3.1% (relative standard deviation, RSD) (for n=5), respectively. Whereas, the precision evaluated by five replicate analysis of a serum and a whole blood sample were 3.3 and 3.8% RSD. An enrichment factor of ca. 3.5 was achieved with the introduction of 0.5 ml aqueous standard solutions at a sample flow rate of 1.0 ml min⁻¹. Recoveries of spiked molybdenum in blood serum and whole blood were in the ranges 96–102 and 94–98%, respectively. The results obtained for two human whole blood certified reference materials were in good agreement with the indicative values.     

Kinetic spectrophotometric method for rapid determination of trace formaldehyde in foods

A simple and sensitive kinetic-spectrophotometric method was developed for the determination of ultra trace amount of formaldehyde in food samples. The method was based on the oxidation of rhodamine B (RhB) by potassium bromate in sulfuric acid medium (formaldehyde as catalyst). The reaction was monitored by measuring the decrease in absorbance of the dye at 515 nm after 6 min. The developed method allowed the determination of formaldehyde in the range of 10–100 μg L⁻¹ with good precision, accuracy and the detection limit was down to 2.90 μg L⁻¹. The relative standard deviations for the determination of 10 and 60 μg L⁻¹ of formaldehyde were 3.0% and 1.9% (n = 10), respectively. The method was found to be sensitive, selective and was applied to the determination of formaldehyde in foods with satisfactory results.     

Determination of phenol, m-, o- and p-cresol, p-aminophenol and p-nitrophenol in urine by high-performance liquid chromatography

A method for the biological monitoring of human exposure to aromatic hydrocarbons, nitrocompounds, amines and phenols has been developed. Phenol, cresols, p-aminophenol, p-nitrophenol and their glucorono- or sulpho-conjugates, were quantified by HPLC; 4-chlorphenol was added as internal standard. After enzymatic hydrolysis, the free compounds were extracted with an organic solvent and analyzed by an isocratic HPLC Perkin Elmer system at ambient temperature and at a flow-rate of 1 ml/min. The column was a reversed-phase Pecosphere 3 x 3 C18 Perkin Elmer; the mobile phase was a 30:70:0.1 (v/v/v) methanol-water-orthophosphoric acid mixture and the chromatogram was monitored at 215 nm. Identification was based on retention time and quantification was performed by automatic peak height determination, corrected for the internal standard. The recovery was ca. 95% for phenol and cresols; 90% for p-nitrophenol; 85% for p-aminophenol; the coefficients of variance were less than 6% within analysis (n = 20) and less than 10% between analysis (n = 20). The detection limits, at a signal/noise ratio of 2, were 0.5 mg/l for phenol and cresols and 1 mg/l for p-aminophenol and p-nitrophenol.     

HPLC determination of Vitamin D(3) and its metabolite in human plasma with on-line sample cleanup

A HPLC method with automated column switching and UV-diode array detection is described for the simultaneous determination of Vitamin D₃ and 25-hydroxyvitamin D₃ (25-OH-D₃) in a sample of human plasma. The system uses a BioTrap precolumn for the on-line sample cleanup. A sample of 1 ml of human plasma was treated with 2 ml of a mixture of ethanol–acetonitrile (2:1 (v/v)). Following centrifugation, the supernatant was evaporated to dryness under a stream of dry and pure nitrogen. The residue was reconstituted in 250 μL of a solution of methanol 5 mmol l⁻¹ phosphate buffer, pH 6.5 (4:1 (v/v)), and a 200 μl aliquot of this solution was injected onto the BioTrap precolumn. After washing during 5 min with a mobile phase constituted by a solution of 6% acetonitrile in 5 mmol l⁻¹ phosphate buffer, pH 6.5 (extraction mobile phase), the retained analytes were then transferred to the analytical column in the backflush mode. The analytical separation was then performed by reverse-phase chromatography in the gradient elution mode with the solvents A and B (Solvent A: acetonitrile–phosphate buffer 5 mmol l⁻¹, pH 6.5; 20:80 (v/v); solvent B: methanol–acetonitrile–tetrahydrofuran, 65:20:15 (v/v)). The compounds of interest were detected at 265 nm. The method was linear in the range 3.0–32.0 ng ml⁻¹ with a limit of quantification of 3.0 ng ml⁻¹. Quantitative recoveries from spiked plasma samples were between 91.0 and 98.0%. In all cases, the coefficient of variation (CV) of the intra-day and inter-day-assay precision was ≤2.80%. The proposed method permitted the simultaneous determination of Vitamin D₃ and 25-OH-D₃ in 16 min, with an adequate precision and sensitivity. However, the overlap of the sample cleanup step with the analysis increases the sampling frequency to five samples h⁻¹. The method was successfully applied for the determination of Vitamin D₃ and 25-OH-D₃ in plasma from 46 female volunteers, ranging from 50 to 94 years old. Vitamin D₃ and 25-OH-D₃ concentrations in plasma were found from 4.30–40.70 ng ml⁻¹ (19.74 ± 9.48 ng ml⁻¹) and 3.1–36.52 ng ml⁻¹ (7.13 ± 7.80 ng ml⁻¹), respectively. These results were in good agreement with data published by other authors.     

Silicon determination by inductively coupled plasma atomic emission spectrometry after generation of volatile silicon tetrafluoride

A method for the determination of silicon by inductively coupled plasma atomic emission spectrometry (ICP-AES) is described. The procedure is based on a discontinuous generation of volatile silicon tetrafluoride in concentrated sulphuric acid medium after injecting 125 μl of 0.1%, w/v sodium fluoride solution into 100 μl of the sample. The gaseous silicon tetrafluoride is fed directly into the ICP torch by a flow of 250 ml min⁻¹ Ar carrier gas. The calibration curve was linear up to at least 100 μg ml⁻¹ of Si(IV) and the absolute detection limit was 9.8 ng working with a solution volume of 100 μl. The relative standard deviation for six measurements of 10 μg ml⁻¹ of Si(IV) was 2.32%. The method was applied to the determination of silicon in water and iron ores.     

Spectrophotometric method for determination of vanadium and its application to industrial, environmental, biological and soil samples

The very sensitive, fairly selective direct spectrophotometric method for the determination of trace amount of vanadium (V) with 1,5-diphenylcarbohydrazide (1,5-diphenylcarbazide) has been developed. 1,5-diphenylcarbohydrazide (DPCH) reacts in slightly acidic (0.0001–0.001 M H₂SO₄ or pH 4.0–5.5) 50% acetonic media with vanadium (V) to give a red–violet chelate which has an absorption maximum at 531 nm. The average molar absorption coefficient and Sandell’s sensitivity were found to be 4.23×10⁴ l mol⁻¹ cm⁻¹ and 10 ng cm⁻² of V^v, respectively. Linear calibration graph were obtained for 0.1–30 μg ml⁻¹ of V^v: the stoichiometric composition of the chelate is 1:3 (V: DPCH). The reaction is instantaneous and absorbance remain stable for 48 h. The interference from over 50 cations, anions and complexing agents has been studied at 1 μg ml⁻¹ of V^v. The method was successfully used in the determination of vanadium in several standard reference materials (alloys and steels), environmental waters (potable and polluted), biological samples (human blood and urine), soil samples, solution containing both vanadium (V) and vanadium (IV) and complex synthetic mixtures. The method has high precision and accuracy (s=±0.01 for 0.5 μg ml⁻¹).     

A23187-mediated Cd uptake by highly stable, polymerized metal-sorbing vesicles

Vesicles formed from the polymerizable phospholipid, 1,2-diacyl-sn-glycero-3-(N-2(methacryloyloxy)ethyl)-phosphocholine, and the crosslinker, 1,2-dihydroxyethylene-bis-acrylamide, exhibit significantly enhanced stability relative to egg phosphatidylcholine (PC) vesicles. As evidenced by absorbance measurements, methacrylate PC vesicles with a 1 : 75 crosslinker-to-lipid molar ratio retain their integrity in up to 20% (v/v) ethanol as opposed to <10% (v/v) for egg PC vesicles. These crosslinked-polymerized vesicles also remain impermeable to Cd²⁺ (in the absence of ionophore) for up to 15 mM octyl glucoside. Furthermore, the crosslinked-polymerized vesicles show enhanced stability under osmotic stress. These inprovements in vesicle robustness are attained without dramatic loss in A23187-mediated Cd²⁺ permeability. The initial Cd²⁺ permeability of crosslinked-polymerized (1 : 75 crosslinker-to-lipid molar ratio) and egg PC vesicles, with A23187 as ionophore, measured 6.0 × 10⁻⁵ and 9.8 × 10⁻⁵ cm s⁻¹, respectively.     

Simultaneous determination of haloperidol and its metabolite, reduced haloperidol, in plasma, blood, urine and tissue homogenates by high-performance liquid chromatography.

A high-performance liquid chromatographic method was developed for the simultaneous determination of haloperidol and reduced haloperidol in human plasma, urine and rat tissue homogenates using bromperidol as an internal standard. The method involved extraction followed by injection of 50-80 microliters of the aqueous layer onto a C18 reversed-phase column. The mobile phase was 0.5 M phosphate buffer-acetonitrile-methanol (58:31:11, v/v/v) and the flow-rate was 0.6 ml/min. The column effluent was monitored by ultraviolet detection at 214 nm. The retention times for reduced haloperidol, haloperidol and bromperidol were 5.4, 7.2 and 8.4 min, respectively. The detection limits for haloperidol and reduced haloperidol in human plasma were both 0.5 ng/ml, and the corresponding values in human urine were both 5 ng/ml. The coefficients of variation of the assay were generally low (below 10.7%) for plasma, urine, blood and tissue homogenates. No interferences from endogenous substances or any drug tested were found.