High-performance Liquid Chromatography Studies Research Articles

Metabolomic evaluation of ginsenosides distribution in Panax genus (Panax ginseng and Panax quinquefolius) using multivariate statistical analysis

Ginseng is any one of the eleven species belonging to the genus Panax of the family Araliaceae and is found in North America and in eastern Asia. Ginseng is characterized by the presence of ginsenosides. Principally Panax ginseng and Panax quinquefolius are the adaptogenic herbs and are commonly distributed as health food markets. In the present study high performance liquid chromatography has been used to identify and quantify ginsenosides in the two subject species and the different parts of the plant (roots, neck, leaves, flowers, fruits). The power of this chromatographic technique to evaluate the identity of botanical material and to distinguishing different part of the plants has been investigated with metabolomic technique such as principal component analysis.Metabolomics provide a good opportunity for mining useful chemical information from the chromatographic data set resulting an important tool for quality evaluation of medicinal plants in the authenticity, consistency and efficacy.

A validated stability indicating HPLC method for determination of sitagliptin

A comparative and stability-indicating reversed phase high performance liquid chromatographic study have been developed and validated for sitagliptin phosphate. The liquid chromatographic determination was achieved isocratically on Poroshell 120 EC-C18 (100 × 4.6 mm, i.d.; particle size, 2.7 µm), Pursuit 5PFP (150 × 4.6 mm, i.d.; particle size, 5 µm) and Chromolith performance RP-18e (100 × 4.6 mm, i.d.; macropore diameter, 2 µm) columns using a mobile phase consisting of methanol:water:triethylamine:acetic acid (60:40:0.1:0.1; v : v : v : v ), at a flow rate 0.5 mL/min and UV detection at 268 nm. The method was linear over the concentration range of 100-1000 µg/mL ( r = 0.9998) with a limit of detection and quantitation of 10 and 30 µg/mL, respectively. All the validation parameters and stability indicating study were studied on Poroshell 120 EC-C18 column, which achieved the best separation. The proposed method has been found to have the required accuracy, selectivity, sensitivity, and precision to assay sitagliptin phosphate in bulk form and in a pharmaceutical dosage form. Degradation products resulting from the stress studies did not interfere with the detection of sitagliptin phosphate that indicates that the assay are stability-indicating assay.

Stability of an anti-stroke peptide: Driving forces and kinetics in chemical degradation

NR2B9c (Lys-Leu-Ser-Ser-Ile-Glu-Ser-Asp-Val) is a 9-amino acid peptide that has been illustrated to be a potential anti-stroke drug. For more effective treatment, suitable drug delivery systems should be developed. However, little is known about the stability of NR2B9c which is essential to its formulation. In this study, a reversed-phase high-performance liquid chromatography (HPLC) was applied to study the forced degradation behavior and stability of NR2B9c. HPLC studies were performed with an C8 column using a mobile phase consisting of acetonitrile (14.5:85.5, v/v) and aqueous solution (0.1% trifluoroacetic acid (TFA) and 0.05M KH2PO4). The flow rate and the wavelength set during HPLC detection were 1.0mL/min and 205nm, respectively. The degradation pattern of NR2B9c aqueous solution followed pseudo first-order kinetics. The degradation rate at pH 7.5 was the slowest according to the plotting V-shaped pH-rate profile. The influence of temperature on the rate of reactions was interpreted in terms of Arrhenius equation (r2>0.98). Thermodynamic parameters were calculated based on Eyring equation (r2>0.98). The concentrations of drug, buffer species, buffer concentrations, oxidation and organic solvents have noticeable effects on the degradation of NR2B9c while ultrasound shows little impact under the experimental conditions. In a word, this study may give a detailed description of stability of NR2B9c.

HPLC analysis ofPhyllanthus amarussamples stored in stability chambers under different conditions and study of the effect on quantification of the phytomarkers phyllanthin and hypophyllanthin

Storage of medicinal plants may cause deterioration of the active principles with time, thus, reducing the efficacy of plants. Therefore, quantification of the active principle is essential before using the crude drug. Phyllanthus amarus (PA) contains lignans, namely, phyllanthin and hypophyllanthin, which shows anti-hepatotoxic activity. In this paper, we highlight the effect of storage conditions on the quantification of bioactive markers by high-performance liquid chromatography (HPLC) analysis in the crude plant material of PA. HPLC analysis of crude PA samples stored for certain period at long-term study (LS, 30 °C and 65% RH), accelerated study (AS, 40°C and 75% RH), and real-time study (RT) conditions was carried out using the LiChroCART Purospher® STAR RP-18 endcapped (250 × 4.6 mm, 5 μm) column along with a Purospher STAR RP 18e (4.0 × 4.0 mm, 5 μm) guard column using methanol:water (70:30) at a flow rate of 0.7 mL min−1 with ultraviolet (UV) detection at 220 nm. The HPLC study indicated that PA ...

Forced degradation behavior of epidepride and development of a stability-indicating method based on liquid chromatography–mass spectrometry

A reversed-phase high-performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was applied to study the forced degradation behavior and stability of epidepride. 123I radioisotope-labeled epidepride, [(-)-N-{[(2S)-1-ethylpyrrolidin-2-yl]methyl}-5-iodo-2,3- dimethoxybenzamide] is a radiotracer with a high affinity for dopamine D2 receptors in the brain and has been used as an imaging agent for single-photon emission computed tomography. HPLC studies were performed using 127I-epidepride (the nonradioactive compound), instead of 123I-epidepride, with an RP-18 column using a mobile phase consisting of methanol, acetonitrile, and ammonium acetate (pH 7.0, 10 mM). The eluent flow rate and the wavelength for HPLC detection were 0.5 mL/min and 210 nm, respectively. The ligand was exposed to acid (1 N HCl) and alkaline (1 N NaOH) media and was subjected to oxidative decomposition at room temperature using 3% H2O2 and to thermal decomposition at 50°C. After various reaction times (30 minutes, 1 hour, 2 hours, 8 hours, and 24 hours), the substances were investigated by HPLC and LC-MS/MS. Although no decomposition products were observed after the acidic, alkaline, and thermal treatments, >80% of the initial amount of 127I-epidepride was oxidized within 24 hours in the presence of H2O2. Only one major oxidation product with an m/z value of 435 was observed, in addition to the 127I-epidepride species (m/z 419). The product was characterized by LC-MS/MS fragmentation, and the deteriorated type and fragmentation pathways were proposed for epidepride.

Effect of Chromatographic Conditions on Enantioseparation of Bovine Serum Albumin Chiral Stationary Phase in HPLC and Thermodynamic Studies

Twelve chiral compounds were enantiomerically resolved on bovine serum albumin chiral stationary phase (BSA-CSP) by high-performance liquid chromatography (HPLC) in reversed-phase modes. Chromatographic conditions such as mobile phase pH, the percentage of organic modifier, and concentration of analyte were optimized for separation of enantiomers. For N-(2, 4-dinitrophenyl)-serine (DNP-ser), the retention factors (k) greatly increase from 0.81 to 6.23 as the pH decreasing from 7.21 to 5.14, and the resolution factor (R(s)) exhibited a similar increasing trend (from 0 to 1.34). More interestingly, the retention factors for N-(2, 4-dinitrophenyl)-proline (DNP-pro) decrease along with increasing 1-propanol in mobile phase (3%, 5%, 7% and 9% by volume), whereas the resolution factor shows an upward trend (from 0.96 to 2.04). Moreover, chiral recognition mechanisms for chiral analytes were further investigated through thermodynamic methods.

The high-performance liquid chromatographic fingerprints study of Awei capsules

Background:Awei Capusules are Hospital preparation for Hyperlipidemia. It was composed by Awei, Magnoliae Officinalis and Polygonum Bistoral etc. Manufacture and quality standard of Awei Capusules had been studied. Results of animal pharmacodynamic and clinical study all displayed that Awei Capusules can reduce serum levels of TC, TG, LDL-C, increases HDL-C/TC. It was safe. It could improve hemorrheology and vessel function of blood stasis animal. On the basis of these, we studied on fingerprint of Awei capsule.Materials and Methods:The gradient elution method was used for analyzing samples on HPLC. Fingerprint similarity calculation software was used for data analysis.Results:We got a good separation of Awei Capusules peaks. There were 15 peaks in fingerprint of Awei capusles. Gallic acid, magnolol and honokiol were identified.Conclusion:HPLC fingerprinting of Awei Capusules can provide to reference. It can control preparations quality of Awei Capusules.

Seasonal growth dynamics and carbon allocation of the wild blueberry plant (Vaccinium angustifoliumAit.)

Kaur, J., Percival, D., Hainstock, L. J. and Privé, J.-P. 2012. Seasonal growth dynamics and carbon allocation of the wild blueberry plant ( Vaccinium angustifolium Ait.). Can. J. Plant Sci. 92: 1145–1154. Field studies were conducted at the Wild Blueberry Research Station, Debert, NS, to examine the carbon allocation dynamics within the wild blueberry (Vaccinium angustifolium Ait.). This was achieved with biweekly measurements of dry weight, soluble sugar and starch levels of the rhizomes, roots, stems/leaves and berries of plants in the vegetative (i.e., sprout phase) and cropping phases of production. Non-structural carbohydrate levels were determined using high-performance liquid chromatography (HPLC). Growth parameters included phenology, stem height, dry weights of the above-ground vegetation (stems and leaves), berries, rhizomes and roots. Interestingly, root growth was observed prior to upright shoot emergence and dry weight for rhizome remained higher compared with stems and leaves. The rhizomes acted as a carbohydrate source during stem and root growth. The developing berry crop appeared to be a strong sink for photo-assimilates, as berries were found to import sucrose and convert it to fructose and glucose during maturation, and HPLC studies further confirmed the increasing levels of fructose and glucose. Given the phenology of the wild blueberry, the results exemplify the importance of the rhizomes as a strong carbohydrate source, especially in the early stages of a growing season when the carbohydrate production is limited.

Orthogonal array design for optimization of hollow-fiber-based liquid-phase microextraction combined with high-performance liquid chromatography for study of the pharmacokinetics of magnoflorine in rat plasma

In this work, a new sample-preparation method based on hollow-fiber liquid-phase microextraction (HF-LPME) was developed for analysis of magnoflorine in rat plasma. Analysis was accomplished by reversed-phase high-performance liquid chromatography (HPLC), with ultraviolet detection by use of a photodiode-array detector. An orthogonal array design (OAD) was found to be effective for optimization of major conditions which may affect the efficiency of HF-LPME. Under the optimized conditions (pH of donor and acceptor phases 12 and 2.0, respectively; extraction time 20 min; stirring speed 800 rpm; and addition of 10 % (w/v) salt), the preconcentration factor for magnoflorine was 355. Calibration curves with reasonable linearity (r(2)≥0.9994) were obtained in the range 10-1000 ng mL(-1). Intra-day and inter-day precision (RSD) were <5.5 % and the limit of detection (LOD) for the analyte was 3.0 ng mL(-1) (S/N=3). The validated method was successfully used for pharmacokinetic studies of magnoflorine in rat plasma after intravenous administration.

MULTIFUNCTIONAL HYDROXYCAMPTOTHECIN-CAPPED Fe3O4 NANOPARTICLES FOR INHIBITING OF CANCER DRUG RESISTANCE

In this study, we have explored the multifunctional hydroxycamptothecin (HCPT)-capped Fe 3 O 4 nanoparticles efficiently targeting adriamycin-resistant K562 cells (KA cells), inducing apoptosis, making hole on KA cell membrane, photothermal therapy and low hemolysis activity. The HCPT functionalized Fe 3 O 4 nanoparticles were characterized by the transmission electron microscopy (TEM) and high performance liquid chromatographic (HPLC) study. Meanwhile, the apoptotic staining and the DNA fragmentation clearly illustrate that the apoptosis rate apparently increased after the treatment with HCPT-capped Fe 3 O 4 (HCPT- Fe 3 O 4) nanoparticles, compared with that of the only HCPT treatment in KA cells. Moreover, our observations also demonstrate the possibility of the photothermal therapy to kill KA cells by using HCPT- Fe 3 O 4 nanoparticles with semiconductor laser. In addition, the blood compatibility of the HCPT- Fe 3 O 4 nanoparticles was tested by hemolysis assay on washing the isolated rat erythrocytes. The results indicate that HCPT- Fe 3 O 4 nanoparticles did not cause aggregation behavior at lower concentration. Thus, it is evident that the HCPT functionalized Fe 3 O 4 nanoparticles could readily induce cellular apoptosis and low hemolysis activity, which could be further utilized for the efficient multimode therapy of cancers.

CHROMATOGRAPHIC ANALYSIS OF DRUG INTERACTIONS IN THE SERUM PROTEOME.

The binding of drugs with serum proteins and binding agents such as human serum albumin, α1-acid glycoprotein, and lipoproteins is an important process in determining the activity and fate of many pharmaceuticals in the body. A variety of techniques have been used to study drug interactions with serum proteins, but there is still a need for faster or better methods for such work. High-performance liquid chromatography (HPLC) is one tool that has been utilized in many formats for these types of measurements. Advantages of using HPLC for this application include its speed and precision, its ability to be automated, its good limits of detection, and its compatibility with a wide range of assay formats and detectors. This review will discuss various approaches in which HPLC can be employed for the study of drug-protein interactions. These techniques include the use of soluble proteins in zonal elution and frontal analysis methods or vacancy techniques such as the Hummel-Dreyer method. Zonal elution and frontal analysis methods that make use of immobilized proteins and high-performance affinity chromatography will also be presented. A variety of applications will be examined, ranging from the determination of free drug fractions to the measurement of the strength or rate of a drug-protein interaction. Newer developments that will be discussed include recent work in the creation of novel mathematical approaches for HPLC studies of drug-protein binding, the use of HPLC methods for the high-throughput screening of drug-protein binding, and the creation and use of affinity monoliths or affinity microcolumns for examining drug-protein systems.

In vivo biodistribution of 131I labeled bleomycin (BLM) and isomers (A2 and B2) on experimental animal models

Bleomycins (BLMs; BLM, A2, and B2) were labeled with 131I and radiopharmaceutical potentials were investigated using animal models in this study. Quality control procedures were carried out using thin layer radiochromatography (TLRC), high performance liquid chromatography (HPLC), and liquid chromatography (LC/MS/MS). Labeling yields of radiolabeled BLMs were found to be 90, 68, and 71%, respectively. HPLC chromatograms were taken for BLM and cold iodinated BLM (127I-BLM). Five peaks were detected for BLM and three peaks for 127I-BLM in the HPLC studies. Two peaks belong to isomers of BLM. The isomers of BLM were purified with using HPLC. Biological activity of BLM was determined on male Albino Wistar rats by biodistribution and scintigraphic studies were performed for BLMs by using New Zelland rabbits. The biodistribution results of 131I-BLM showed high uptake in the stomach, the bladder, the prostate, the testicle, and the spinal cord in rats. Scintigraphic results on rabbits agrees with that of biodistributional studies on rats. The scintigraphy of radiolabeled isomers (131I-A2 and 131I-B2) are similiarly found with that of 131I-BLM.

Edaravone directly reacts with singlet oxygen and protects cells from attack

Aims Protective effects of edaravone, an approved medicine for acute brain infarction in Japan, on cell death induced by singlet oxygen ( 1O 2) were examined. Main method The 1O 2 scavenging activity was examined by direct analysis of near-infrared luminescence in a cell-free system and by fluorospectrometry in the presence of cells. The protective effects of edaravone on 1O 2-induced cell death were examined, using rat neuronal B50 cells. Cell death was evaluated by mitochondrial respiration (MTT assay), confocal microscopy and time-lapse imaging. The chemical reaction of edaravone with 1O 2 was examined by production analysis using high performance liquid chromatography (HPLC). Key findings When rose Bengal (RB) in D 2O was irradiated by a 514 nm laser beam, the signal of 1O 2 was observed. Edaravone suppressed the 1O 2 signal more potently than azide, a 1O 2 scavenger. When B50 cells were irradiated by 525 nm green light in the RB solution, production of 1O 2 and induction of cell death were observed. The fluorospectrometric study and the MTT assay revealed that 100–400 µM edaravone suppressed the 1O 2 production and attenuated cell death in a concentration-dependent manner. Confocal microscopy and the time-lapse imaging revealed that edaravone prevented the impairment of membrane integrity and the progression of cell death induced by 1O 2. The HPLC study revealed that edaravone chemically reacted with 1O 2 and changed another compound. Significance Since 1O 2 is possibly involved in post-ischemic neuronal damage, the clinically approved curative effects of edaravone on acute brain infarction might be attributed to its potent 1O 2 scavenging activity.

Separation of structurally similar nocathiacin analogues by reversed phase chromatography

The complete separation of structurally similar compounds has been a challenge due mainly to their similarity on physical and chemical properties. In the present study, a simple and effective chromatographic method to separate and purify nocathiacin acid from its structural analogue nocathiacin I was developed. After evaluating mobile phase compositions on the retention characteristics by reversed phase high-performance liquid chromatography (HPLC), the elution order of nocathiacin I and nocathiacin acid was completely reversed, and the resolution value between the two analogues was improved, by varying pH value and ionic strength, to greater than 10 from merged peaks under initial conditions. In addition, a preparative isolation of nocathiacin acid was performed by reversed phase column chromatography under the guidance of the HPLC study. This chromatographic method resulted in an efficient process to obtain pure nocathiacin acid with a recovery rate of 83%. The present approach offers a new methodology for the separation of structurally closely related secondary metabolites.

Physicochemical study on microencapsulation of hydroxypropyl-β-cyclodextrin in dermal preparations

Objective: To investigate the effect of hydroxypropyl-β-cyclodextrin (HP-β-CD) concentration on the physicochemical properties of the sunscreen agents, namely oxybenzone (Oxy), octocrylene (Oct), and ethylhexyl-methoxy-cinnamate (Cin), in aqueous solution and cream formulations. Methods: The inclusion complexes of sunscreen agents with hydroxypropyl-β-cyclodextrin (HP-β-CD) in aqueous solution and solid phase were studied by UV-vis spectrophotmetery, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and 13C-NMR techniques. The photodegradation reaction of the sunscreen agents' molecules in lotion was explored using UV-vis spectrophotometry and high-performance liquid chromatography (HPLC). Results: The formation of the inclusion complexes was confirmed experimentally using DSC, SEM, and 13C-NMR. The results of spectrophotometric and HPLC studies have shown that the inclusion complexation with HP-β-CD has the potential to enhance the photostability of the selected sunscreen agents in lotion. HPLC results indicated that HP-β-CD has approximately increases the photostability of Oct by six- to eightfold. Moreover, the presence of HP-β-CD in lotion controlled the isomerization process of Cin to a certain degree, which was found to be a function of the amount of HP-β-CD added. Conclusions: It has been demonstrated that the photostability of the tested sunscreen agents has been enhanced upon forming inclusion complexes with HP-β-CD in lotion. The results of this study demonstrate that HP-β-CD can be utilized as photostabilizer additive for enhancing the photostability of the sunscreen agents' molecules.

HPLC Study of Uremic Fluids Related to Optical Dialysis Adequacy Monitoring

Purpose The aim of this study was to investigate uremia-related high-performance liquid chromatography (HPLC) ultraviolet (UV) absorbance profiles of serum and spent dialysate and to study the removal of uremic retention solutes in connection with optical dialysis adequacy monitoring. Methods 10 uremic patients were investigated using online spectrophotometry at a wavelength of 280 nm over the course of 30 hemodialysis treatments. The dialysate and blood samples were taken and analyzed simultaneously using standard biochemical methods and reversed-phase HPLC. Filters with cutoff at 3 kDa and 70 kDa were used for the pre-treatment of the serum. The chromatographic peaks were detected by a UV detector at wavelengths of 254 and 280 nm. Results This study indicated that the main solute responsible for UV absorbance in the spent dialysate is a low-molecular-weight, water-soluble, non-protein-bound compound uric acid (UA). Three additional uremic retention solutes – creatinine (CR), indoxyl sulphate (IS) and hippuric acid (HA) – were identified from the HPLC profiles. The number of detected HPLC peaks was not significantly different for a serum filtered through the 3 kDa or 70 kDa cutoff filters, and was lower for the spent dialysate, indicating that the molecular weight (MW) of the main UV chromophores in the uremic fluids did not exceed 3 kDa. The reduction ratio (RR) estimated by the total area of HPLC peaks at 254 nm and 280 nm in the serum and by the online UV absorbance at 280 nm was best related to the removal of small water-soluble non-protein bound solutes like urea (UR), CR and UA. Conclusions The present study contributes new information on the removal of uremic retention solutes during hemodialysis and on the origin of the optical dialysis adequacy monitoring signal.

Erythritol is a sweet antioxidant

ObjectiveHyperglycemia, oxidative stress, and the onset and progression of diabetic complications are strongly linked. Reduction of oxidative stress could be of utmost importance in the long-term treatment of diabetic patients. The chronic nature of the disease calls for a mode of antioxidant intake that can be sustained easily, e.g., by the diet. Erythritol, a simple polyol, could be such a compound. It is orally available, well tolerated, and its chemical structure resembles that of mannitol, a well-known hydroxyl radical (HO•) scavenger. MethodsWe studied the antioxidant properties of erythritol in vitro and subsequently determined its antioxidant activity and its vasoprotective effect in the streptozotocin diabetic rat. ResultsErythritol was shown to be an excellent HO• radical scavenger and an inhibitor of 2,2′-azobis-2-amidinopropane dihydrochloride–induced hemolysis but inert toward superoxide radicals. High-performance liquid chromatographic and electron spin resonance spectroscopy studies showed that the reaction of erythritol with hydroxyl radicals resulted in the formation of erythrose and erythrulose by abstraction of a carbon-bound hydrogen atom. In the streptozotocin diabetic rat, erythritol displayed an endothelium-protective effect and, in accordance with the in vitro experiments, erythrose was found in the urine of erythritol-consuming rats. ConclusionErythritol acts as an antioxidant in vivo and may help protect against hyperglycemia-induced vascular damage.

Germinated Buckwheat extract decreases blood pressure and nitrotyrosine immunoreactivity in aortic endothelial cells in spontaneously hypertensive rats

Thee present study analysed the quantification of rutin in raw buckwheat extract (RBE) and germinated buckwheat extract (GBE) by high performance liquid chromatography (HPLC), and examined changes in body weight, systolic blood pressure (SBP) and nitrotyrosine (a marker for peroxynitrite formation) immunoreactivity in aortic endothelial cells in spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto (WKY) rats after treatment with RBE and GBE for 5 weeks. In the HPLC study, RBE and GBE contained a mean content of rutin of 1.52 +/- 0.21 and 2.92 +/- 0.88 mg/g, respectively. In the 600 mg/kg GBE-treated group, SBP was lower than that in the 600 mg/kg RBE-treated group. The treatment with RBE and/or GBE significantly reduced oxidative damage in aortic endothelial cells by lowering nitrotyrosine immunoreactivity. These results suggest that GBE has an antihypertensive effect and may protect arterial endothelial cells from oxidative stress.

Image-Guided Enzyme/Prodrug Cancer Therapy

The success of enzyme/prodrug cancer therapy is limited by the uncertainty in the delivery of the enzyme in vivo. This study shows the use of noninvasive magnetic resonance (MR) and optical imaging to image the delivery of a prodrug enzyme. With this capability, prodrug administration can be timed so that the enzyme concentration is high in the tumor and low in systemic circulation and normal tissue, thereby minimizing systemic toxicity without compromising therapeutic efficiency. The delivery of a multimodal imaging reporter functionalized prodrug enzyme, cytosine deaminase, was detected by MR and optical imaging in MDA-MB-231 breast cancer xenografts. Stability of the enzyme in the tumor was verified by (19)F MR spectroscopy, which detected conversion of 5-fluorocytosine to 5-flurouracil. The optimal time window for prodrug injection determined by imaging was validated by immunohistochemical, biodistribution, and high-performance liquid chromatographic studies. The therapeutic effect and systemic toxicity of this treatment strategy were investigated by histologic studies and tumor/body weight growth curves. The delivery of the functionalized enzyme in tumors was successfully imaged in vivo. The optimal time window for prodrug administration was determined to be 24 h, at which time the enzyme continued to show high enzymatic stability in tumors but was biodegraded in the liver. Significant tumor growth delay with tolerable systemic toxicity was observed when the prodrug was injected 24 h after the enzyme. These preclinical studies show the feasibility of using a MR-detectable prodrug enzyme to time prodrug administration in enzyme/prodrug cancer therapy.

HPLC‐Based Chemotaxonomy of Florida Bay Phytoplankton: Difficulties in Coastal Environments

This report covers high performance liquid chromatography (HPLC) derived pigment based chemotaxonomy for phytoplankton studies in a turbid coastal environment. Sediment resuspension brings detritus with pheopigments and other chlorophyll (CHL) breakdown products into the water column and hampers data interpretation. Two hundred sixty six water samples from Florida Bay were analyzed from monthly collections (Sept. 2000–Aug. 2002). Comparing biomarker estimated CHLa to measured CHLa, we found a mean of 105.4% (Std. Dev.=24.7; R2=0.9547) and when data was restricted to those samples with <10% pheopigments, estimations improved to 102±16%. It is concluded that all HPLC studies on phytoplankton communities must report the percentage pheopigments.