scholarly journals Rapid Postcolumn Methodology for Determination of Paralytic Shellfish Toxins in Shellfish Tissue

2008 ◽  
Vol 91 (3) ◽  
pp. 589-597 ◽  
Author(s):  
Wade A Rourke ◽  
Cory J Murphy ◽  
Ginette Pitcher ◽  
Jeffery M van de Riet ◽  
B Garth Burns ◽  
...  
Keyword(s):  
Reversed Phase ◽  
Mouse Bioassay ◽  
Working Standard ◽  
Shellfish Toxins ◽  
Paralytic Shellfish Toxins ◽  
Paralytic Shellfish ◽  
Relative Standard ◽  
Phase Column ◽  
Reversed Phase Column

Abstract A rapid liquid chromatographic (LC) method with postcolumn oxidation and fluorescence detection (excitation 330 nm, emission 390 nm) for the determination of paralytic shellfish toxins (PSTs) in shellfish tissue has been developed. Extracts prepared for mouse bioassay (MBA) were treated with trichloroacetic acid to precipitate protein, centrifuged, and pH-adjusted for LC analysis. Saxitoxin (STX), neoSTX (NEO), decarbamoylSTX (dcSTX), and the gonyautoxins, GTX1, GTX2, GTX3, GTX4, GTX5, dcGTX2, and dcGTX3, were separated on a polar-linked alkyl reversed-phase column using a step gradient elution; the N-sulfocarbamoyl GTXs, C1, C2, C3, and C4, were determined on a C-8 reversed-phase column in the isocratic mode. Relative toxicities were used to determine STX-dihydrochloride salt (diHCl) equivalents (STXeq). Calibration graphs were linear for all toxins studied with STX showing a correlation coefficient of 0.999 and linearity between 0.18 and 5.9 ng STX-diHCl injected (equivalent to 3.9128 g STXeq/100 g in tissue). Detection limits for individual toxins ranged from 0.07 g STXeq/100 g for C1 and C3 to 4.1 g STXeq/100 g for GTX1. Spike recoveries ranged from 76 to 112 in mussel tissue. The relative standard deviation (RSD) of repeated injections of GTX and STX working standard solutions was <4. Uncertainty of measurement at a level of 195 g STXeq/100 g was 9, and within-laboratory reproducibility expressed as RSD was 4.6 using the same material. Repeatability of a 65 g STXeq/100 g sample was 3.0 RSD. Seventy-three samples were analyzed by the new postcolumn method and both AOAC Official Methods for PST determination: the MBA (y = 1.22x + 13.99, r2 = 0.86) and the precolumn LC oxidation method of Lawrence (y = 2.06x + 12.21, r2 = 0.82).

scholarly journals Determination of 4-Hexylresorcinol in Shrimp by Liquid Chromatography with Fluorescence Detection

2000 ◽  
Vol 83 (1) ◽  
pp. 241-244 ◽  
Author(s):  
Klaas M Jonker ◽  
Colinda P Dekker
Keyword(s):  
Liquid Chromatography ◽  
Chromatographic Analysis ◽  
Reversed Phase ◽  
Fluorimetric Detection ◽  
Relative Standard ◽  
Liquid Chromatographic Analysis ◽  
Liquid Chromatographic ◽  
Phase Column ◽  
Reversed Phase Column

Abstract A method was developed to determine 4-hexylresorcinol in shrimp meat. The procedure is based on extraction of test portions with methanol followed by liquid chromatographic analysis of the extracts, using a reversed-phase column and fluorimetric detection (excitation: 280 nm, and emission: 310 nm). The confidence interval of the recovery in working range of 1.5–2.5 mg/kg was 81.6 ± 0.8%. The relative standard deviation in the working range was 2.1%. Limits of quantitation and detection were 6.59 and 1.98 ng/mL extract, respectively, corresponding to 0.26 and 0.08 mg/kg in shrimp.

scholarly journals Multiresidue Determination of Pesticides in Sediment by Ultrasonically Assisted Extraction and Gas Chromatography/Mass Spectrometry

2005 ◽  
Vol 88 (5) ◽  
pp. 1440-1451 ◽  
Author(s):  
Kuniaki Kawata ◽  
Takashi Asada ◽  
Kikuo Oikawa ◽  
Akiko Tanabe
Keyword(s):  
Column Chromatography ◽  
Internal Standard ◽  
Reversed Phase ◽  
Normal Phase ◽  
Gas Chromatography Mass Spectrometry ◽  
Sediment Samples ◽  
Relative Standard ◽  
Phase Column ◽  
Reversed Phase Column

Abstract Agas chromatographic/mass spectrometric (GS/MS) method was developed for the multiple determination of pesticides in sediment. The investigated pesticides included 85 compounds, i.e., 13 fungicides, 43 herbicides, and 29 insecticides. The pesticides were extracted from sediment samples by an ultrasonically assisted procedure. The extract was cleaned up by using reversed-phase column chromatography followed by normal-phase column chromatography. A styrene-divinylbenzene copolymer cartridge and a silica gel cartridge were used as the reversed-phase column and the normal-phase column, respectively. The compounds were determined by GC/MS with 2 internal standard compounds. The overall recoveries were 70–105%, and the relative standard deviations ranged from 1.5 to 18%. The minimum detectable concentrations were 2–10 μg/kg. This method was successfully applied to sediment samples from the Shin River in Niigata, Japan. Twenty-five pesticides (6 fungicides, 11 herbicides, and 8 insecticides) were detected in the sediment samples. The concentrations of the detected pesticides ranged from 3 to 69 μg/kg. Herbicides were found May through July; insecticides and fungicides were found July through August, and during July through September, respectively. The presence of pesticides in the river sediment was correlated with the time of pesticide application in the Shin River basin.

Comparison Evaluation of Liquid Chromatographic and Bioassay Methods of Analysis for Determination of Paralytic Shellfish Poisons in Shellfish Tissues

1989 ◽  
Vol 72 (4) ◽  
pp. 670-673 ◽  
Author(s):  
Julia E Salter ◽  
Ralph J Timperi ◽  
Laura J Hennigan ◽  
Lynda Sefton ◽  
Hilary Reece
Keyword(s):  
Coastal Waters ◽  
Mouse Bioassay ◽  
Surveillance Program ◽  
Fluorescence Detector ◽  
Paralytic Shellfish Toxins ◽  
Response Range ◽  
Paralytic Shellfish ◽  
State Surveillance ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method was compared with the AOAC mouse bioassay method (18.086-18.092) for determination of paralytic shellfish toxins in shellfish tissues. Shellfish samples were collected from Massachusetts coastal waters as part of a state surveillance program, and extracts of shellfish meat were analyzed for toxins by using both analytical methods. Overall correlation of the LC and bioassay methods is good (r = 0.943), but for samples with toxicities < 100 jug saxitoxin/100 g shellfish meat, the correlation is significantly less (r = 0.531). Limits of detection are 10 fig saxitoxin/ 100 g shellfish meat and 40 fig saxitoxin/100 g shellfish meat for the LC and bioassay methods, respectively. Analytical capacity of the LC method is limited to 12 samples/person-day compared with 30 samples/ person-day for the bioassay. Sampling capacity of the LC method could be increased by using a fluorescence detector with a wider response range, which would eliminate the need for dilution of concentrated samples.

Improved liquid-chromatographic determination of caffeine in plasma.

1980 ◽  
Vol 26 (9) ◽  
pp. 1351-1354 ◽  
Author(s):  
J Blanchard ◽  
J D Mohammadi ◽  
K A Conrad
Keyword(s):  
Plasma Sample ◽  
Chromatographic Determination ◽  
Reversed Phase ◽  
Small Sample ◽  
Small Animals ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Phase Column ◽  
Reversed Phase Column

Abstract We describe a rapid, specific, and sensitive liquid-chromatographic micro-method for caffeine in plasma. Each plasma sample can be assayed within about 15 min of its receipt. Samples are denatured with acetonitrile, centrifuged, and the supernate is chromatographed on a reversed-phase column. Only 100 microL of plasma is required, and concentrations as low as 0.3 mg/L can be measured accurately. Other xanthines and their metabolites do not interfere. The small sample required makes the procedure ideally suited for measuring caffeine in the plasma of infants and small animals as well as adults.

scholarly journals Proficiency Testing of Eight French Laboratories in Using the AOAC Mouse Bioassay for Paralytic Shellfish Poisoning: Interlaboratory Collaborative Study

2000 ◽  
Vol 83 (2) ◽  
pp. 305-310 ◽  
Author(s):  
Martial LeDoux ◽  
Sherwood Hall ◽  
Madeleine Bohec ◽  
Bernard Charron ◽  
Magali Esnault ◽  
...  
Keyword(s):  
Water Solution ◽  
Collaborative Study ◽  
Paralytic Shellfish Poisoning ◽  
Mouse Bioassay ◽  
Shellfish Poisoning ◽  
Paralytic Shellfish ◽  
Relative Standard ◽  
Standard Solution ◽  
Overall Performance

Abstract In an interlaboratory study, 8 French laboratories were tested for their proficiency in using the AOAC mouse bioassay for paralytic shellfish poisoning (PSP). Each laboratory received 1 saxitoxin (STX) standard solution, 1 STX acidified water solution for determination of the titer, 1 noncontaminated shellfish sample, 1 naturally contaminated shellfish sample, and 2 shellfish samples spiked, respectively, at low (152.8 μg STX/100 g meat) and moderate (334.7 μg STX/100 g meat) levels. All samples were analyzed in duplicate. Mean recoveries were 35.1% for the low level and 46.6% for the moderate level. Relative standard deviations (RSD) for within-laboratory variations (repeatability) ranged from 5.4 to 9.8%; RSD for between-laboratory variations (reproducibility) varied from 7.8 to 39.6%, depending on STX level. On the basis of overall performance, all 8 participating laboratories were proficient in their use of the AOAC mouse bioassay.

Determination of Paralytic Shellfish Toxins in Shellfish by Receptor Binding Assay: Collaborative Study

2012 ◽  
Vol 95 (3) ◽  
pp. 795-812 ◽  
Author(s):  
Frances M Van Dolah ◽  
Spencer E Fire ◽  
Tod A Leighfield ◽  
Christina M Mikulski ◽  
Gregory J Doucette ◽  
...  
Keyword(s):  
East Coast ◽  
Collaborative Study ◽  
Hplc Method ◽  
Mouse Bioassay ◽  
Sea Scallop ◽  
Paralytic Shellfish Toxins ◽  
Paralytic Shellfish ◽  
Aoac Method ◽  
The U.S

Abstract A collaborative study was conducted on a microplate format receptor binding assay (RBA) for paralytic shellfish toxins (PST). The assay quantifies the composite PST toxicity in shellfish samples based on the ability of sample extracts to compete with 3H saxitoxin (STX) diHCl for binding to voltage- gated sodium channels in a rat brain membrane preparation. Quantification of binding can be carried out using either a microplate or traditional scintillation counter; both end points were included in this study. Nine laboratories from six countries completed the study. One laboratory analyzed the samples using the precolumn oxidation HPLC method (AOAC Method 2005.06) to determine the STX congener composition. Three laboratories performed the mouse bioassay (AOAC Method 959.08). The study focused on the ability of the assay to measure the PST toxicity of samples below, near, or slightly above the regulatory limit of 800 (μg STX diHCl equiv./kg). A total of 21 shellfish homogenates were extracted in 0.1 M HCl, and the extracts were analyzed by RBA in three assays on separate days. Samples included naturally contaminated shellfish samples of different species collected from several geographic regions, which contained varying STX congener profiles due to their exposure to different PST-producing dinoflagellate species or differences in toxin metabolism: blue mussel (Mytilus edulis) from the U.S. east and west coasts, California mussel (Mytilus californianus) from the U.S. west coast, chorito mussel (Mytilus chiliensis) from Chile, green mussel (Perna canaliculus) from New Zealand, Atlantic surf clam (Spisula solidissima) from the U.S. east coast, butter clam (Saxidomus gigantea) from the west coast of the United States, almeja clam (Venus antiqua) from Chile, and Atlantic sea scallop (Plactopecten magellanicus) from the U.S. east coast. All samples were provided as whole animal homogenates, except Atlantic sea scallop and green mussel, from which only the hepatopancreas was homogenized. Among the naturally contaminated samples, five were blind duplicates used for calculation of RSDr. The interlaboratory RSDR of the assay for 21 samples tested in nine laboratories was 33.1%, yielding a HorRat value of 2.0. Removal of results for one laboratory that reported systematically low values resulted in an average RSDR of 28.7% and average HorRat value of 1.8. Intralaboratory RSDr, based on five blind duplicate samples tested in separate assays, was 25.1%. RSDr obtained by individual laboratories ranged from 11.8 to 34.9%. Laboratories that are routine users of the assay performed better than nonroutine users, with an average RSDr of 17.1%. Recovery of STX from spiked shellfish homogenates was 88.1–93.3%. Correlation with the mouse bioassay yielded a slope of 1.64 and correlation coefficient (r2) of 0.84, while correlation with the precolumn oxidation HPLC method yielded a slope of 1.20 and an r2 of 0.92. When samples were sorted according to increasing toxin concentration (μg STX diHCl equiv./kg) as assessed by the mouse bioassay, the RBA returned no false negatives relative to the 800 μg STX diHCl equiv./kg regulatory limit for shellfish. Currently, no validated methods other than the mouse bioassay directly measure a composite toxic potency for PST in shellfish. The results of this interlaboratory study demonstrate that the RBA is suitable for the routine determination of PST in shellfish in appropriately equipped laboratories.

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