LC Method Research Articles

LC–MS/MS assay method development and validation for the simultaneous quantification of Solifenacin and Mirabegron in human plasma

The present study intended to develop a simple and novel Liquid Chromatography–Mass Spectrometry/ Mass spectrometry (LC–MS/MS) method for the simultaneous quantification of solifenacin and mirabegron, a combined medication used for the treatment of overactive bladder symptoms in human plasma. Tolterodine drug is used as an internal standard in the study. Both the analytes and internal standard were isolated from 100 μL plasma samples by liquid-liquid extraction and then chromatographed on Zorbax C18 (4.6 mm×50 mm, 5 μm) column with a mobile phase consisting of methanol and 5mM ammonium formate in the ratio of 25:75 (v/v) pumped at 0.3 mL/min. The method had a chromatographic total run time of 5 min. The developed method gave symmetric peak at a retention time of 2.50 min, 2.99 min and 1.18 min respectively for solifenacin, mirabegron and nifedipine satisfying all the peak properties as per USP guidelines. The mass spectral characterization of separated analytes in the LC method was performed using mass detector operated at Multiple Reaction Monitoring mode with precursor-toproduct ion transitions at m/z of 363 to m/z of 110 as MH+ ion for solifenacin, m/z of 397 to m/z of 239 as MH+ ion for mirabegron. A very sensitive limit of detection of 7.5 ng/mL was observed and showed calibration curve linear over the concentration range of LLOQ to 1000 ng/mL. The other validation parameters were found to have acceptable accuracy, precision, linearity and selectivity. The mean extraction concentration was acceptable and very high for both the analytes in HQC, MQC and LOQ levels. Various stability studies of solifenacin and mirabegron such as freeze-thaw, short term, long term, auto-sampler and dry extract stability proved that the method was stable. Based on the results, it can be proved that the method was accurate, precise and specific for the simultaneous analysis of solifenacin and mirabegron in human plasma.

Precolumn Derivatization High-Performance Liquid Chromatography for Determination of Perfluorocarboxylic Acids in Catalytic Degradation Solutions.

Perfluoroalkyl carboxylic acids (PFCAs), a series of ubiquitous contaminants in the global environment, attracted much attention due to their potential for high bioaccumulation and toxicity to various organisms. There are a lot of measurement requests in currently increasing degradation studies of PFCAs, which usually rely on expensive liquid chromatography-mass spectrometry (LC-MS). The degradation solutions containing high-concentration PFCAs can easily cause the pipeline pollution of the LC/MS instrument, which is usually used for trace analysis of environmental samples. In this study, a simple and reliable precolumn derivatization LC method coupled with an ultraviolet detector (UV) was developed for the determination of the main PFCAs (C4-9) of environmental concern. These PFCAs in degradation solutions were crosslinked to UV-responsive 3, 4-diphenylamine (DCA) by a carbodiimidization method, followed by a simple solid-phase extraction (SPE) cleanup, and quantitatively measured using a conventional LC-UV instrument. Compared to previously reported precolumn derivatization methods, this new derivatization approach has the advantages such as mild reaction conditions, easy operation, enhanced stability of derivatives, and low cost. The instrumental limits of detection (ILDs) for the targeted PFCAs in organic and aqueous mediums were 0.2–0.5 and 0.6–1.5 mg/L, respectively. The method has been successfully applied to the determination of PFCAs in catalytic degradation solutions and recommended for use in other assays involving relatively high-concentration PFCAs.

Development and validation of reversed phase HPLC method for determination of apremilast in bulk and pharmaceutical dosage form

The present study describes a novel Reversed Phase High-Performance LC method for the determination and estimation of Apremilast (APR) in bulk and pharmaceutical formulation. The chromatographic separation was carried out on Agilent 1120LC Compact system with Binary gradient system connected to UV- Absorbance Detector. Acetonitrile: (30mM) Potassium dihydrogen phosphate buffer pH adjusted to 3.0 with o-phosphoric acid (60:40 v/v), and flow rate 1.0ml/min with an injection volume of 20 μL was selected as it gave sharp symmetric peak for APL with minimal tailing and with desired elution graph.The separation was carried out at a room temperature and the eluents were observed by UV - Vis detector set at 236 nm. The retention time of APR obtained was at 4.46 minutes. The calibration curve for APR was linear (r2= 0.995) over thetested concentration range of 10 - 60 μg/ ml with LOD and LOQ of 0.93 μg/ml and 2.82μg/ml respectively. A recovery of APR in tablet formulation was observed in the range of 98.40 -100.00 %. Thus the proposed method for APR was found to be feasible for the estimation of APR in bulk as well as pharmaceutical dosage form.

Comprehensive degradation study of lipoglycodepsipeptide antibiotic ramoplanin by liquid chromatography and mass spectrometry

Development of new antibiotics is of the utmost importance in the battle against antimicrobial resistance. One of the promising candidates in the fight against resistant bacteria is ramoplanin, a cyclic lipoglycodepsipeptide derived from a fermentation broth. In order to obtain effective and safe pharmaceutical product on the market, development of reliable analytical method for the evaluation of ramoplanin's purity is vital. In the present work, an LC method was developed, validated and used during stability testing of ramoplanin, in solid state and in solution. Forced degradation study was performed by subjecting the sample to different stress conditions (acid and base hydrolysis, oxidation, humidity, heat and light) and the observed degradation products were elucidated using mass spectrometry. The study revealed significant degradation of ramoplanin under alkaline conditions, leading to formation of lacton hydrolysis product. The results of the study clearly demonstrate that the hydrolysis of the lacton ring is predominant path of ramoplanin's degradation. However, other significant degradation routs were also observed. Based on the MS/MS results, degradation pathways of ramoplanin are proposed.

Identification and validation of small molecule analytes in mouse plasma by liquid chromatography-tandem mass spectrometry: A case study of misidentification of a short-chain fatty acid with a ketone body.

Recently, there has been growing interest in short-chain fatty acids (SCFA) and ketone bodies (KB) due to their potential use as biomarkers of health and disease. For instance, these diet-related metabolites can be used to monitor and reduce the risk of immune response, diabetes, or cardiovascular diseases. Given the interest in these metabolites, different targeted metabolomic methods based on UPLC-MS/MS have been developed in recent years to detect and quantify SCFA and KB. In this case study, we discovered that applying an existing validated, targeted UPLC-MS/MS method to mouse plasma, resulted in a fragment ion (194m/z) being originally misidentified as acetic acid (a SCFA), when its original source was 3-hydroxybutyric acid (a KB). Therefore, we report a modified, optimized LC method that can separate both signals. In addition, the metabolite coverage was expanded in this method to detect up to eight SCFA: acetic, propanoic, butyric, isobutyric, 2-methylbutyric, valeric, isovaleric, and hexanoic acids, two KB: 3-hydroxybutyric, and acetoacetic acids, and one related metabolite: 3-hydroxy-3-methylbutyric acid. The optimization of this method increased the selectivity of the UPLC-MS/MS method towards the misidentified compound. These findings encourage the scientific community to increase efforts in validating the original precursor of small molecule fragments in targeted methods.

Inside Back Cover: Development of a validated liquid chromatography–diode array detection method for simultaneous determination of olanzapine and fluoxetine in their combined formulation: Application to greenness assessment

DOI: 10.1002/sscp.202200013 The cover picture shows the development of a greener LC method for simultaneous determination of olanzapine and fluoxetine in a fixeddose combination. This current AES approach assessed method greenness corresponding to reagents and instruments used. Afterward, risk assessment and DoE based robust method was developed and validated to match the method intent for routine application purpose.

Chemometrics-assisted development of a validated LC method for simultaneous estimation of temozolomide and γ-linolenic acid: Greenness assessment and application to lipidic nanoparticles

The described work entails the development of a simple, sensitive, green, and robust high-performance liquid chromatographic (HPLC) method for simultaneous estimation of temozolomide (TMZ) and γ-linolenic acid (GLA). The chemometric factor screening study helped identify the critical method parameters optimized using Box-Behnken design for improved understanding and enhancing the method performance. Chromatographic separation was performed on a Kinetex® C18 column (150 × 4.6 mm, 5 µm particle size) using methanol: water (pH adjusted to 3.5 using 0.5% v/v O-phosphoric acid) as the mobile phase at 0.5 mL/min flow rate and diode array detection between 210 and 360 nm. The linearity of the method was observed for concentrations of TMZ and GLA ranging between 1 and 100 µg.mL−1 (R2 = 0.999, p < 0.05). Accuracy evaluation showed good percent recovery within 97.9–100%, while intra- and inter-day precision showed RSD values within 0.37%-1.01%. The limit of detection and quantification for TMZ was found to be 0.75 and 1.0 μg.mL−1, respectively, while the values 0.55 and 1.0 μg.mL−1, respectively, were observed for GLA. System suitability (96.9–102.8%), its limits, and robustness evaluation indicated good percent recovery within, while RSD values were found to be within the acceptable limit of less than 2%. The method was specific for its ability to detect the analytes and their degradation products during forced degradation studies, which also indicated that TMZ was highly prone to alkaline conditions while GLA showed mild degradation in all the studied conditions. The estimation of both the analytes from lipid nanoparticles formulation showed good values for total drug content (82.6–85.3%), entrapment efficiency (95.4 to 98.7%), and drug loading (25.2 to 38.4%). Overall, the results indicated that the developed method was reliable for its accuracy, precision, sensitivity, and specificity for simultaneous estimation of the analytes. The method was found to be stability-indicating in nature and suitable for simultaneous estimation of TMZ and GLA from the developed nanoparticles formulation. Further, employing a greenness assessment approach established the method greenness.

Development of a solvent-free micellar HPLC method for determination of five antidiabetic drugs using response surface methodology

Various antidiabetic combinations have recently been used to improve the management of type II diabetes mellitus. The first time a totally green mixed micellar LC method was used to analyze the biguanide metformin (MET) in a mixture with two sulfonylurea antidiabetics, glipizide (GPZ) and glimepiride (GLM), as well as pioglitazone (PGZ) as a thiazolidinedione derivative antidiabetic and repaglinide (RPG) as an insulin secretagogue antidiabetic. Response surface methodology (RSM) was used to optimize the method by using central composite design (CCD). The design space that represents the robustness zone was identified. Analytes were separated by elution of an aqueous mobile phase containing Brij-35 (12.05 mM) and SDS (76.25 mM) at pH 3.72 on a Symmetry C18 column (75*4.6 mm, 3.5 m) at a flow rate of 1 mL/min and UV detection at 225 nm and 210 nm, respectively, for MET and the other analytes. The laboratory mixtures and pharmaceutical products of the examined drugs were successfully determined using the established method. Using the Green Analytical Procedure Index (GAPI) and Analytical Greenness Metric (AGREE) principles, the greenness of the created method was analyzed and compared to previously reported methods. In comparison to previous methods, the new method was shown to be more efficient and effective.

Development &amp; Validation of RP-HPLC Method for Quantitative Estimation of Dasatinib and its Impurities in Pharmaceutical Dosage Form

Aim: The primary objective of the research work is to develop a effective, sensitive, economical and simple reverse phase HPLC method for the separation and quantification of Dasatinib and its impurities are described in tablet formulations.&#x0D; Study Design: HPLC based quantification studies.&#x0D; Place and Duration of Study: Department of Chemistry, Acharya Nagarjuna University, Guntur, Andhra Pradesh between April 2021 and August 2021.&#x0D; Methodology: Separation and quantification of Dasatinib and its impurities are done by using an Inertsil ODS-3V, 250 x 4.6 mm, 5µm and the mobile phase consists of two Channels A and B. Channel-A: pH 5.80 phosphate buffer : acetonitrile (90:10 v/v) and Channel-B: acetonitrile : water (90:10 v/v). The flow rate is 1.0 ml/min. The column temperature was maintained at 25°C and sample temperature was maintained at 25°C, injection volume 10 µL and wavelength fixed at 320nm UV-detection.&#x0D; Results: There is no interference of diluent and placebo at Dasatinib and impurities peaks. The elution order and the retention times of impurities and Dasatinib obtained from individual standard preparations and mixed standard preparations are comparable.&#x0D; The limit of detection (LOD) and limit of quantitation (LOQ) for Dasatinib standard 0.147&amp;0.048 µg/mL, impurity-A 0.334&amp;0.110 µg/mL, impurity-C 0.184&amp;0.061 µg/mL, impurity-D 0.136&amp;0.045 µg/mL, impurity-E 0.089&amp;0.029 µg/mL and impurity-F 0.222 &amp; 0.073 µg/mL respectively.&#x0D; The linearity results for Dasatinib and all the impurities in the specified concentration range are found satisfactory, with a correlation coefficient greater than 0.99.Calibration curve was plotted and correlation co-efficient for Dasatinib and its impurities found to be 1.000, 0.9999, 0.9912, 1.000, 0.9932 and 0.9922 respectively.&#x0D; The accuracy studies were shown as % recovery for Dasatinib and its impurities at specification level. The limit of % recovered shown is in the range of 80 and 120% and the results obtained were found to be within the limits. Hence the method was found to be accurate.&#x0D; The method has validated as per ICH guidelines and all the validation parameters are satisfy the ICH Q2 specification acceptance limits&#x0D; Conclusion: The developed LC method was validated with respect to specificity, precision, linearity, ruggedness and robustness. Therefore this method has high probability to adopt in pharmaceutical industry for regular analysis of Dasatinib tablet formulations.

Ultrahigh-performance supercritical fluid chromatography for intraclass separation of lipids: Investigation of general principles

Powerful chromatographic techniques are required for lipidomic analyses due to the extreme complexity of natural lipidomes. In the past few years, ultrahigh-performance supercritical fluid chromatography (UHPSFC) has proven to be a good alternative to conventional LC methods for comprehensive lipidomic analysis. The goal of this work was to study UHPSFC intraclass separation of lipids according to the fatty acyl composition. The effects of column chemistry, mobile phase composition and gradient, flow rate, back pressure, temperature, and column coupling on intraclass separation of lipids were widely investigated and discussed. In general, UHPSFC exhibited interclass selectivity together with intraclass separation of lipids according to their total number of double bonds and acyl chain lengths. Moreover, separations of diacylglycerol and lysophosphatidylcholines regioisomers were achieved in some cases. The nature of the stationary phase showed the most prominent effect on UHPSFC intraclass selectivity, while other chromatographic conditions were used for partial improvement in resolution of lipid species. An octadecyl-based stationary phase showed excellent separation of nonpolar lipid species, including triacylglycerol isobars; however, it provided poor peak shapes and limited retention time reproducibility for polar lipids. Diol- and 1-aminoanthracene-based columns provided the best inter- and intraclass resolution of most lipids. The main benefit for UHPSFC separation of complex lipid samples is the combination of the acyl chain/double bond intraclass separation of lipids with excellent lipid class selectivity, which can facilitate mass spectrometry detection and quantitation of trace species without ion suppression effects.

Retraction Note to: LC Method Development and Validation for the Determination of Ropivacaine Hydrochloride in Bulk Drug and Pharmaceutical Formulations

Retraction Note to: LC Method Development and Validation for the Determination of Ropivacaine Hydrochloride in Bulk Drug and Pharmaceutical Formulations

Therapeutic Treatment Plan Optimization during the COVID-19 Pandemic: A Comprehensive Physicochemical Compatibility Study of Intensive Care Units Selected Drugs

Background: The SARS-CoV-2 pandemic has resulted in a dramatic rise of the demand for medical devices and drugs. In this context, an important shortage of programmable syringe pumps, used to administrate different drugs in intensive care units, was seen. The opportunity of administrating combinations of five intensive care units selected drugs (Sufentanil, Clonidine, Loxapine, Midazolam, and Ketamine) was considered. Methods: The drug mixtures were studied in a pure form or diluted in NaCl 0.9% or G5%. Twenty-six possible combinations of the five drugs were produced in glass vials or polypropylene syringes and stored at 25 °C for 14 days. The LC method was implemented to study drugs combinations in the presence of the degradation products. The clearness and pH were also monitored. Results: All the 26 possible combinations displayed adequate physicochemical stability at 25 °C: at least 3 days and 7 days, respectively, for the dilution in 0.9% NaCl or glucose 5%, and the pure drug products mixtures. Conclusions: The study provided sufficient stability results, covering the medication administration period of at least three days. The combination of more than two drugs offers the advantage of minimizing the individual doses and reduces unwanted side-effects. Hence, this study opens up the possibility of combining the five drugs in one single syringe, which is useful especially under the current circumstances associated with an important shortage of programmable syringe pumps and pharmaceuticals.

Development and validation of ion-pairing HPLC-CAD chromatography for measurement of Islatravir’s phosphorylated intermediates

Biocatalytic processes have become more prevalent in the pharmaceutical industry, leading to analytical challenges not faced when characterizing more traditional synthetic routes. A novel one-pot biocatalytic process has been established for Islatravir, an HIV reverse transcriptase translocation inhibitor for the treatment and prevention of HIV-1. As a one-pot reaction, the Islatravir chemistry contains multiple intermediates that are not isolated. Additionally, these unisolated intermediates have no chromophores, making traditional LC-UV techniques ineffective for characterization. A hydrophilic interaction chromatography (HILIC) method with a charged aerosol detector (CAD) was initially developed, however numerous inorganic species present in the one-pot reaction were retained; this led to co-elution of compounds and poor peak shapes. An innovative ion-pairing LC method was developed in order to resolve inorganic species, intermediates, and the API, for use during in-process control of the Islatravir biocatalytic reaction. Aided by a volatile ion-pairing reagent compatible with the CAD, this method successfully retains and resolves the highly polar intermediates of interest and Islatravir API. This novel method was successfully validated and has allowed the Islatravir biocatalytic process to be fully characterized from the early intermediates through the final API within the one-pot reaction without the need for isolations. This novel ion-pairing HPLC-CAD technique lays the groundwork for method development on current and future biocatalytic-produced drug substances.

Research on Real-time Simulation of Power Electronic Circuits Based on Simscape

In order to realize hardware-in-the-loop simulation of commonly used power electronic circuits, a method of joint simulation using Simcape and field programmable gate array (FPGA) is proposed. This article adopts a switch modeling method suitable for high-frequency characteristics, namely the switch function method. It effectively solves the problem of rigidity non-convergence in the modeling of the binary resistance method, as well as the transient error caused by the binary LC method when the system state is switched with the increase of the switching frequency, which reduces the simulation accuracy. Taking the single-phase full-bridge inverter circuit as an example, a Simscape model based on the state-space averaging method was established, and the HDL code was automatically generated using the Simscape HDL Workflow Advisor tool, and the hardware-in-the-loop simulation was completed with FPGA. Finally, the simulation results with Simulink comparison verify the effectiveness and feasibility of the method.

Development and Validation of Stability Indicating RP-HPLC Method for Quantitative Estimation of Ornidazole and its Impurities in Ornidazole Injection

The analysis of improved RP-HPLC method for the separation and quantification of Ornidazole and its impurities are described. Samples are analysed by means of reverse phase (RP-HPLC) using an Symmetry shield RP18, 250 x 4.6 mm, 5µm, and the mobile phase consists of phosphate buffer: methanol in the ratio of 70:30 %v/v. The flow rate is 1.0 ml/min. The column temperature was maintained at 25°C and sample temperature was maintained at ambient (25°C) and wavelength fixed at 318nm UV-detection. It is found that the method of RP-HPLC with UV-detection system for the analysis of Ornidazole impurities are straight forward and applied in qualitative and quantitative analysis. The developed LC method was validated with respect to specificity, precision, linearity, accuracy, solution stability and robustness. Validation study compared as per ICH guideline.

Non-psychoactive cannabinoids identification by linear retention index approach applied to a hand-portable capillary liquid chromatography platform.

The aim of the present research was the application of the linear retention index (LRI) system for the identification of non-psychoactive cannabinoids using a portable LC instrument. The miniaturization, viz. the use of very low quantities of mobile phase, enabled the development of a compact mobile system to be used for in situ analysis, also according to a green and cost-saving approach. In particular, new capillary LC (cap-LC) methods coupled with UV detection were developed for the analysis of extracts of Cannabis sativa L. Two setups were explored to achieve the efficient separation of twenty-four cannabinoids: a single column setup which exploited a sub-2µm packing to increase the chromatographic resolution, and a dual-column setup based on the serial connection of two different stationary phases, each coupled to an UV detector. The latter allowed the determination of two LRI values for each analyte, thus increasing the identification power. Moreover, since two different wavelengths were used on the LED-based UV detectors, the ratio of the absorbances measured on each chromatographic trace represented a third identification criterion, thus fulfilling the recommendations of the Scientific Working Group for The Analysis of Seized Drugs (SWDRUG) about the categories of analytical techniques to be used and the minimum number of parameters required for the unambiguous identification of drugs. The obtained results could be used for the development of a novel analytical method for fast and automatic in situ forensic investigations and hemp breeding programs, also minimizing the consumption of both sample and solvent.

Simultaneous quantitative determination of insulin aspart and insulin degludec in human plasma using simple shoot LC method.

Combining short-acting and long-acting insulin analogs was a real challenge that was overcome by NovoNordisk through the co-formulation of insulin aspart and insulin degludec in single-dosage form. The proposed study provides a simple, short, and reliable HPLC method with diode array detection that is developed and validated for the simultaneous determination of insulin aspart and insulin degludec in human plasma. The proposed method achieved good separation between the two analytes utilizing a C8 column at 35°C in a very short run time (6min), with a simple, low-cost, and reliable extraction method through precipitation of plasma protein. Gradient elution was applied using a mobile phase consisting of 0.1M sodium sulfate (pH3.4) and acetonitrile. The method was validated according to EMA Guideline on Bioanalytical Validation. The proposed method had a linear range from 3.0 to 300 μg/mL for insulin aspart and from 3.5 to 300 μg/mL for insulin degludec. The intra- and inter-day precision of insulin aspart were 0.36-3.33% and 1.59-8.84%, respectively, and accuracy was between 10.06 and 3.09% The intra- and inter-day precision of insulin degludec were 0.29-1.93% and 0.89-5.14%, respectively, and accuracy was between -5.29 and 3.91%.

LC method for quantitative determination of Ciprofloxacin in ophthalmic ointment

The objective of the study was to validate an analytical method for the quantification of ciprofloxacin in ophthalmic ointment by high performance liquid chromatography. The chromatographic separation of ciprofloxacin hydrochloride was achieved on a Thermo hypersil Gold C18 column using UV detection at 278 nm. The optimized mobile phase consisted of a mixture of 0.025 M phosphoric acid with a pH previously adjusted with triethylamine to 3.0 and acetonitrile (85:15, v / v). The validation method yielded good results demonstrated statistically that the method was linear, precise, accurate, specific and robust. No interference from any components of the pharmaceutical dosage forms was observed.

Development and Validation of Difference Spectrophotometric Method for Simultaneous Estimation of Rosuvastatin Calcium and Aspirin in Marketed Formulation

Objective: To develop and validate a simple Vierordt method for the simultaneous estimation of rosuvastatin calcium (RSV ca) and aspirin (ASP) in fixed dose combination capsules by difference spectrophotometry technique in the UV region. Difference spectrophotometry is based on the utilization of difference absorption spectra corresponding to the same compound obtained at two different pH values. &#x0D; Methodology: The difference in spectral characteristics for the two drugs was observed in 0.01N acetic acid and 0.01N NaOH. The simultaneous equations were developed using difference absorbance and absorptivity values of the two drugs measured and calculated at 243.2nm and 297nm for RSV ca and ASP respectively.&#x0D; Results: Two drugs have shown very good linearity in the concentration range of 10-100µg/ml. The methods were validated as per ICH guidelines for the limit of detection, the limit of quantification, accuracy, and precision, which were found to be within the acceptable limits. The validated method was successfully applied for the analysis of rosuvastatin calcium and aspirin in fixed dose combination capsules.&#x0D; Conclusion: Because this approach is simple and does not require a particular programme, it can be used as a substitute for LC methods in quality control laboratories that lack the necessary equipment for those techniques.&#x0D; &#x0D; &#x0D;

A Generic LC-HRMS Screening Method for Marine and Freshwater Phycotoxins in Fish, Shellfish, Water, and Supplements

Phycotoxins occur in various marine and freshwater environments, and can accumulate in edible species such as fish, crabs, and shellfish. Human exposure to these toxins can take place, for instance, through consumption of contaminated species or supplements and through the ingestion of contaminated water. Symptoms of phycotoxin intoxication include paralysis, diarrhea, and amnesia. When the cause of an intoxication cannot directly be found, a screening method is required to identify the causative toxin. In this work, such a screening method was developed and validated for marine and freshwater phycotoxins in different matrices: fish, shellfish, water, and food supplements. Two LC methods were developed: one for hydrophilic and one for lipophilic phycotoxins. Sample extracts were measured in full scan mode with an Orbitrap high resolution mass spectrometer. Additionally, a database was created to process the data. The method was successfully validated for most matrices, and in addition, regulated lipophilic phycotoxins, domoic acid, and some paralytic shellfish poisoning toxins could be quantified in shellfish. The method showed limitations for hydrophilic phycotoxins in sea water and for lipophilic phycotoxins in food supplements. The developed method is a screening method; in order to confirm suspected compounds, comparison with a standard or an additional analysis such as NMR is required.