Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Chloramines”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 559 records · Page 31Linked to original sources
PubMed1991

Potential role of histamine monochloramine in a rabbit model of ileitis.

Histamine chloramines, derived from the chlorination of histamine by granulocyte-derived oxidants, are potential mediators of intestinal injury and dysfunction in states of atopy or inflammation. We assessed the ability of histamine monochloramine to increase epithelial permeability in rabbit distal small intestine and determined whether the conditions for histamine chloramine formation are favorable in a rabbit model of ileitis. Epithelial permeability, quantified by the blood-to-lumen clearance of 51Cr-labeled ethylenediaminetetraacetic acid, was enhanced by luminal perfusion with either histamine or histamine monochloramine (10 microM), although the latter was twice as effective (p less than 0.05). In a rabbit model of ileitis induced by a luminal solution of acetic acid (200 mM) and casein (10 mg/ml) there was a marked increase in epithelial permeability and in the release into the lumen of histamine, myeloperoxidase, 6-keto-prostaglandin F1 alpha and protein. These results suggest that the conditions are favorable for histamine chloramine formation and that histamine and histamine chloramine may impair the integrity of the epithelial barrier.

Acute Disease↗
PubMedDate not supplied

Liquid chromatographic determination of para-toluenesulfonamide in edible fillet tissues from three species of fish.

Chloramine-T (N-sodium-N-chloro-p-toluene-sulfonamide) is a candidate therapeutic drug for treating bacterial gill disease, a predominant disease of a variety of fish species. Research has been initiated to obtain the U.S. Food and Drug Administration's (FDA) approval for the use of chloramine-T on a variety of fish species. An attribute of a therapeutic aquaculture drug that must be characterized before the FDA approves its use is depletion of the drug's marker residue (the drug's parent compound or metabolite of highest concentration in an edible tissue). para-Toluenesulfonamide (p-TSA) is the primary degradation product and marker residue for chloramine-T in rainbow trout. To conduct residue depletion studies for chloramine-T in fish, a robust analytical method sensitive and specific for p-TSA residues in edible fillet tissue from a variety of fish was required. Homogenized fillet tissues from rainbow trout (Oncorhynchus mykiss), walleye (Stizostedion vitreum), and channel catfish (Ictalurus punctatus) were fortified at nominal p-TSA concentrations of 17, 67, 200, 333, and 1000 ng/g. Samples were analyzed by isocratic reversed-phase liquid chromatography (LC) with absorbance detection at 226 nm. Mean recoveries of p-TSA ranged from 77 to 93.17%; relative standard deviations ranged from 1.5 to 14%; method quantitation limits ranged from 13 to 18 ng/g; and method detection limits ranged from 3.8 to 5.2 ng/g. The LC parameters produced p-TSA peaks without coelution of endogenous compounds and excluded chromatographic interference from at least 20 chemicals and drugs of potential use in aquaculture.

Animals↗
PubMed1991

Nonradical oxidants of the phagocyte type induce the activation of plasmatic single chain- urokinase.

Single chain- urokinase (scu-PA) is the proenzyme of the plasminogen activator urokinase (tcu-PA). In human blood scu-PA is of great stability. Activated phagocytes generate large amounts of single chain- urokinase and of reactive oxidants (chloramines and HOCl). Since these cells participate in physiologic fibrinolysis, we were interested in the interaction between plasmatic scu-PA and chloramines. The oxidants dose dependently induce the activation of plasmatic scu-PA. Optimal activation of scu-PA occurs at about 3-5 mmol/l of chloramine-T. The findings suggest a control mechanism of scu-PA stability/activity by oxidatively modifiable plasma proteins, such as alpha-2-antiplasmin. The oxidation mechanism seems to be mediated by singlet molecular oxygen, an excited oxygen species. Basing on this scu-PA/oxidant synergism a sensitive and fast functional assay of scu-PA in human plasma is presented. Plasmatic inhibitors normally interfering with functional scu-PA measurements are inactivated by addition of chloramine-T, imitating the physiological oxidants generated by activated phagocytes. The scu-PA concentration in plasma of n = 36 healthy individuals has been determined to be 5.8 +/- 1.6 ng/ml. The lower detection limit of plasma scu-PA by the procedure described is about 1.5 ng/ml of plasma. By means of this technique scu-PA concentration during thrombolytic therapy can be measured within minutes in undiluted (direct) plasma samples, allowing adjustments of the scu-PA dosage. The present study gives further credence for a role of singlet molecular oxygen, possibly a new type of locally acting hormones (autacoid), in the regulation of the fibrinolytic pathway.

Adult↗
PubMed1991

[An experimental study on cleaning efficacy of several root canal irrigants].

Seventy-two extracted anterior teeth were subjected to routine biomechanical instrumentation and irrigated with one of the six irrigation liquids: normal saline, 3% hydrogen peroxide, 2% chloramine, 3% hydrogen peroxide and 2% chloramine by turns, 1% glutaraldehyde, and 1% metronidazole. The roots were split and examined under light microscope as well as SEM. Statistical analysis showed that a combination of hydrogen peroxide with chloramine, chloramine or glutaraldehyde was more effective than saline or hydrogen peroxide in removing the debris.

Chloramines↗
PubMed1986

The interaction between the activator agents batrachotoxin and veratridine and the gating processes of neuronal sodium channels.

The depolarization of frog sciatic nerves by the Na channel-activating toxins, batrachotoxin and veratridine, was studied using the sucrose-gap technique. To study the interaction between the activators and the gating processes of Na channels, we measured the depolarizations of unstimulated nerves, of nerves during repetitive stimulation, and of nerves whose Na channel inactivation process had been pharmacologically modified. Stimulation enhanced the rates of depolarization by the activators but did not effect the steady state depolarization values. Of the three inhibitors of Na channel inactivation that were tested (Leiurus alpha-scorpion toxin, chloramine T, and Ni2+), only Leiurus toxin enhanced the potencies of the activators. Neither chloramine T nor Ni2+ had any effect on the steady state level of depolarization produced by either activator. Both chloramine T and Ni2+, however, enhanced the rate of batrachotoxin action, although neither affected the rate of veratridine action. Leiurus toxin also potentiated the effects of the activators in chloramine T-treated nerves. We tested the interaction between the Na channel activators and a class of agents, local anesthetics, that stabilize a non-conducting state of the Na channel. The presence of lidocaine inhibited the depolarization produced by addition of either activator, although the addition of lidocaine subsequent to the development of batrachotoxin-induced depolarization produced repolarization very weakly and slowly. We also found that the lidocaine homologue, RAC 109I, was about 3 times as potent as its stereoisomer, RAC 109II, in its ability both to reduce the compound action potential amplitude and to inhibit the veratridine-induced depolarization.

Action Potentials↗
PubMed1987

[Sensitivity to chlorine-containing disinfectants of Salmonella typhi strains with transmissible drug resistance].

Sensitivity of 201 S. typhi strains to antibiotics and chlorine containing disinfectants was studied. The strains were isolated in the regions of the Left Bank Ukraine. Among the typhoid cultures the proportion of R+ strains was on the whole equal to 29.3 per cent. Chloramine resistant strains amounted to 21.8 per cent. Among chloramine resistant strains the number of the cultures carrying R plasmids was 3 times higher than that of the strains sensitive to disinfectant. Simultaneous transfer of the R plasmid and chloramine resistance to the recipient strain suggested that resistance of the S. typhi strains to chloramine was of plasmid nature.

Anti-Bacterial Agents↗
PubMed1976

[Bactericidal effect of Dikonit].

The research centre of the Lachema nat Bohumín has developed new disinfectants with active chlorine on the basis of chlorinated derivatives of cyanuric acid. According to the physical and chemical properties, Dikon (sodium dichlorisocyanurate) was chosen as the best of these products; Later on, Dikon was given the trade mark Dikonit. Its minimum content of active chlorine is 55%. The purpose of the work was to test its bactericidal effect and to compare it with the effect of chloramin B. Tests on carriers and under practical conditions have demonstrated that, with the same content of active chlorine in solutions in practical use, Dikonit has almost the same bactericidal effect as Chloramin B produced so far. Due to this good bactericidal effect, Dikonit is a suitable means for prophylactic and focal disinfection in animal production and provides a good enrichment of the disinfectants based on active chlorine and produced in Czechoslovakia. It is recommended for prophylactic disinfection to use 1% solutions of Dikonit which are able to give the same effect in all parameters as warm solutions of 2-per-cent Chloramin B. The effective concentration to be used for focal disinfections can be deduced only approximately from the resistance of the infective agent with respect to the concentrations of Chloramin B, recommended as yet. An exact determination of the effective concentration would require experimental verification.

Bacteria↗
PubMed1983

Characterization of human prostatic acid phosphatase radioiodinated by four different procedures.

Prostatic acid phosphatase was labeled by four different iodination procedures: chloramine-T, insoluble or soluble lactoperoxidase, and Bolton-Hunter. Enzyme labeled by the chloramine-T procedure had suboptimal precipitation characteristics in immunoassays, with 36 to 67% of the tracer precipitated in antibody excess. Analysis of the tracer on 7.5% sodium dodecyl sulfate polyacrylamide gel showed that as much as 30% of the radioactivity migrated away from the protein within 6 minutes after the electrophoretic run was begun. The nature of this fast migrating radioiodinated component was not determined. The failure to obtain a tracer labeled by the chloramine-T procedure with optimal immunoprecipitation characteristics led to investigation of alternate radioiodination procedures. Insoluble or soluble lactoperoxidase was less effective than chloramine-T in producing a tracer suitable for radioimmunoassay. In contrast, the Bolton-Hunter procedure produced a tracer that had optimal precipitation characteristics; 88 to 91% of the tracer was precipitated in antibody excess. The tracer was further purified by affinity chromatography to minimize the possibility of other protein contaminants compromising the specificity of a radioimmunoassay for the enzyme.

Acid Phosphatase↗
PubMed1994

Formation of 1-[123I]iodobutane in labeling [123I]iomazenil by iododestannylation: implications for the reaction mechanism.

The benzodiazepine receptor tracer [123I]iomazenil (Ro 16-0154, IMZ) can be prepared in close to theoretical specific activity by the reaction of its tributyltin precursor (IMZ-SnBu3) with [123I]NaI in the presence of Iodogen. However, the labeling reaction is associated with variably high amounts of a volatile 123I byproduct. The purpose of these experiments was to characterize the volatile byproduct and to examine the effect on the course of the reaction of the following variables: solvent (MeOH, EtOH, HOAc, H2O), pH (2-7), oxidizing agent (chloramine-T, Iodogen, AcO2H), reaction temperature (22-128 degrees C) and structure of ArSnR3. The order of reactivity of oxidizing agents, at 22 degrees C for 30 min, was chloramine-T > Iodogen >> AcO2H. Raising the pH above 5.8 reduced the labeling, whereas raising the temperature increased the yield up to a maximum at 120 degrees (90%); at higher temperatures, decomposition occurred. The best conditions were 50 micrograms precursor, 50 microL 0.02 M chloramine-T; in aqueous HOAc (pH 3.3) at 120 degrees for 30 min. Variable amounts of volatile byproduct were observed for chloramine-T at different temperatures (2-21%) and for the three oxidizing agents at room temperature (3-22%). By contrast, the Bu3Sn derivatives of IBF, epidepride, beta-CIT and the Me3Sn derivative of beta-CIT gave high labeling yields with peracetic acid at room temperature, and < or = 2% volatile radioactivity. The volatile byproduct from the [123I]IMZ preparations was identified as I-[123I]iodobutane by its trapping characteristics and by its retention time in two different HPLC systems. Volatile activity was not generated in the absence of Bu3Sn precursor and was not due to the presence of impurities in the tributylstannyl precursor.

Butanes↗
PubMed2005

The effect of boiling water on disinfection by-product exposure.

Chloraminated and chlorinated waters containing bromide were used to determine the impact of boiling on disinfection by-product (DBP) concentrations. No significant changes were detected in the concentrations of the dihalogenated haloacetic acids (DXAAs) (i.e., dichloro-, bromochloro-, dibromoacetic acid) upon boiling of chloraminated water, whereas the levels of the trihalogenated haloacetic acids (TXAAs) (i.e., trichloro- (TCAA), bromodichloro- (BDCAA), dibromochloroacetic acid (DBCAA)) decreased over time (e.g., 9-37% for TCAA). Increased DXAA concentrations (58-68%) were detected in the boiled chlorinated sample, which likely resulted from residual chlorine reacting with DXAA precursors. TCAA concentration was unchanged after boiling chlorinated water for 1 min, but a 30% reduction was observed after 5 min of boiling. BDCAA concentrations decreased 57% upon boiling for 1 min and were completely removed after 2 min of boiling, whereas DBCAA was removed after boiling chlorinated water for 1 min. Trihalomethane concentrations were reduced in both chloraminated (74-98%) and chlorinated (64-98%) water upon boiling. Boiling chloraminated water for 1 min reduced chloroform concentration by 75%. Chloroform was reduced by only 34% in chlorinated water after a 1 min boil, which indicates that simultaneous formation and volatilization of chloroform was occurring. Most of the remaining DBPs (e.g. haloketones, chloral hydrate, haloacetonitriles) were removed by at least 90% after 1 min of boiling in both samples. These data suggest that other mechanisms (e.g., hydrolysis) may have been responsible for removal of the non-volatile DBPs and further highlight the importance of examining individual species when estimating thermal effects on DBP concentrations.

Acetates↗
PubMed2006

The fate of wastewater-derived NDMA precursors in the aquatic environment.

To assess the stability of precursors of the chloramine disinfection byproduct N-nitrosodimethylamine (NDMA) under conditions expected in effluent-dominated surface waters, effluent samples from four municipal wastewater treatment plants were subjected to chlorination and chloramination followed by incubation in the presence of inocula derived from activated sludge. Samples subjected to free chlorine disinfection showed lower initial concentrations of NDMA precursors than those that were not chlorinated or were disinfected with pre-formed chloramines. For chloraminated and control (unchlorinated) treatments, the concentration of NDMA precursors decreased by an average of 24% over the 30-day incubation in samples from three of the four facilities. At the fourth facility, where samples were collected on three different days, NDMA precursor concentrations decreased by approximately 80% in one sample and decreased by less than 20% in the other two samples. In contrast to the low reactivity of the NDMA precursors, NDMA disappeared within 30 days under the conditions employed in these experiments. These results and measurements made in an effluent-dominated river suggest that although NDMA may be removed after wastewater effluent is discharged, wastewater-derived NDMA precursors could persist long enough to form significant concentrations of NDMA in drinking water treatment plants that use water originating from sources that are subjected to wastewater effluent discharges.

Biodegradation, Environmental↗
PubMed2006

Breakpoint chlorination and free-chlorine contact time: implications for drinking water N-nitrosodimethylamine concentrations.

North American drinking water utilities are increasingly incorporating alternative disinfectants, such as chloramines, in order to comply with disinfection by-product (DBP) regulations. N-Nitrosodimethylamine (NDMA) is a non-halogenated DBP, associated with chloramination, having a drinking water unit risk two to three orders of magnitude greater than currently regulated halogenated DBPs. We quantified NDMA from two full-scale chloraminating water treatment plants in Alberta between 2003 and 2005 as well as conducted bench-scale chloramination/breakpoint experiments to assess NDMA formation. Distribution system NDMA concentrations varied and tended to increase with increasing distribution residence time. Bench-scale disinfection experiments resulted in peak NDMA production near the theoretical monochloramine maximum in the sub-breakpoint region of the disinfection curve. Breakpoints for the raw and partially treated waters tested ranged from 1.9:1 to 2.4:1 (Cl(2):total NH(3)-N, M:M). Bench-scale experiments with free-chlorine contact (2h) before chloramination resulted in significant reductions in NDMA formation (up to 93%) compared to no free-chlorine contact time. Risk-tradeoff issues involving alternative disinfection methods and unregulated DBPs, such as NDMA, are emerging as a major water quality and public health information gap.

Chlorine↗
PubMed2003

Effect of temperature and disinfection strategies on ammonia-oxidizing bacteria in a bench-scale drinking water distribution system.

The establishment of ammonia-oxidizing bacteria (AOB), a group of autotrophic microorganisms responsible for nitrification in chloraminated distribution systems, was studied in a bench-scale distribution system. The potential significance of temperature and disinfectant residual associated with chloramination in full-scale drinking water distribution systems was assessed. Biofilm development was primarily monitored using AOB abundance and nitrite concentrations. The bench-scale system was initially operated under typical North American summer (22 degrees C) and fall (12 degrees C) temperatures, representing optimal and less optimal growth ranges for these microorganisms. Additional experimentation investigated AOB establishment at a suboptimal winter distribution system temperature of 6 degrees C. The effect of chloramine residual on AOB establishment was studied at higher (0.2-0.6mg/L) and lower (0.05-0.1mg/L) ranges, using a 3:1 (w/w) chlorine:ammonia dosing ratio. Conditions were selected to represent those typically found in a North American distribution system, in areas of low flow and longer retention times, respectively. Finally, the effect of a free chlorine residual on an established nitrifying biofilm was briefly examined. Results clearly indicate that AOB development occurs at all examined temperatures, as well as at selected monochloramine residuals. The maintenance of a disinfectant residual was difficult at times, but was more inhibitory to the nitrifying biofilm than the lower temperature. It can be concluded from the data that nitrification may not be adequately inhibited during the winter months, which may result in more advanced stages of nitrification the following season. Free chlorination can be effective in controlling AOB activity in the short term, but may not prevent reestablishment of a nitrifying biofilm upon return to chloramination.

Ammonia↗
PubMed2002

Hemodialysis-associated methemoglobinemia in acute renal failure.

Patients on maintenance hemodialysis are vulnerable to chloramine toxicity if chloramines are inadequately removed. We report two critically ill patients with acute renal failure who developed methemoglobinemia during hemodialysis in the intensive care unit. During the same period, methemoglobin levels measured from 30 patients in the outpatient dialysis facility were undetectable. Methemoglobin levels normalized when the carbon filtration system of the portable dialysis machine was replaced with a larger unit to remove chloramines more effectively. Causes, treatment, and prevention of chloramine toxicity in patients receiving dialysis in the intensive care unit are discussed.

Acute Kidney Injury↗
PubMed2001

Regulation of apoptosis by vitamin C. Specific protection of the apoptotic machinery against exposure to chlorinated oxidants.

We have investigated the ability of intracellular vitamin C to protect human umbilical vein endothelial cells from exposure to hypochlorous acid (HOCl) and a range of derived chloramines. Ascorbate provided minimal protection against the cytotoxicity induced by these oxidants, as measured by propidium iodide uptake. In contrast, there was a marked effect on apoptosis, monitored by caspase-3 activation and phosphatidylserine exposure. Extended incubation of the cells with glycine chloramine or histamine chloramine completely blocked apoptosis initiated in the cells by serum withdrawal. This effect was significantly abrogated by ascorbate. Inhibition of apoptosis required the oxidant to be present for an extended period after serum withdrawal and occurred prior to caspase-3 activation. General protection of thiols by ascorbate was not responsible for the protection of apoptosis, because intracellular oxidation by HOCl or chloramines was not prevented in supplemented cells. The results suggest a new role for vitamin C in the regulation of apoptosis. We propose that, by protection of an oxidant-sensitive step in the initiation phase, ascorbate allows apoptosis to proceed in endothelial cells under sustained oxidative stress.

Antioxidants↗
PubMed2007

The fibrinogen antigenic turbidimetric assay (FIATA): the X2x test--the corrected chi-square comparison against the control-mean.

Vancomycin precipitates fibrinogen. The turbidity induced by this vancomycin-fibrinogen interaction is used to establish a simple standardized antigenic assay for plasmatic fibrinogen, the FIATA. 1 mM vancomycin or 2 mM chloramine-T inactivates 50% of fibrinogen in human plasma. In contrast to chloramine-T, vancomycin does not react in NaJ-based photometric assay for chloramines,vancomycin does not inactivate the singlet oxygen-sensible antithrombin III, and the vancomycin action against fibrinogen is not changed in spite of the presence of the 1O2 quenchers methionine or ascorbic acid. The FIATA is performed as follows: to 25 microL plasma 50 microL PBS are added and the absorbance (A) at 405 nm is read. Then 50 microL FIATA-reagent, consisting of 4.4 mM vancomycin in PBS, are added. After 2 minutes (RT) DeltaA is determined and standardized against a plasma pool of 100% of norm (2.8 g/L) fibrinogen. The FIATA is nearly linear up to a fibrinogen concentration of about 150% of norm (4.2 g/L), resulting in a DeltaA of about 600 mA. The lower detection limit is 4% of norm (0.1 g/L). The intra-assay and interessay CV values are < 4%. The normal range of FIATA is 100% +/-20% (x- +/- 1 SD). In = 321 or 344 unselected patient plasmas the FIATA (x- = 130%; SD = 52% or 43%) correlated with the functional fibrinogen assays a) modified Clauss-Method (x- = 4.1 g/L; SD =1.7 g/L) with r = 0.755 and b) FIFTA (x- = 124%; SD = 40%) with r = 0.813. The vancomycin/fibrinogen interaction (binding of about 16 molecules of vancomycin/molecule of fibrinogen) can be used to purify fibrinogen out of plasma. Vancomycin also clouds dysfunctional fibrinogen (fibrinogen in presence of EDTA or chloramine-T)or soluble fibrin. Vancomycin-reacted fibrinogen stimulates tissue type plasminogen activator (t-PA) up to about 20-fold. The experimental data are analyzed by a new significance test: the two foldYates-corrected chi-square comparison against the mean value ofthe control-collective, called the Chi2x - Test. The P < .05 significance barrier calculated with the Chi2x - Test is equivalent to that calculated with the Fisher's Exact Test. The FIATA might be considered an interesting screening test for inactive fibrinogen forms or soluble fibrin, as eg in disseminated intravascular coagulation. Fibrinogen precipitation by vancomycin within the blood vessel might explain why vancomycin has to be infused slowly (< 10 mg/min) to prevent nephrotoxicity. The FIATA is of such a simplicity that the determination of fibrinogen antigen in plasma can be performed anywhere--even outside a hospital--within seconds. Thus, the presented FIATA might contribute to extra hospital testing of patients for assessing their risk for myocardial or cerebral ischemia/infarction.

Antigens↗
PubMed2006

Exposure to trichloramine and respiratory symptoms in indoor swimming pool workers.

The association between swimming pool characteristics and activities of employees and respiratory symptoms in employees was studied. Trichloramine levels were measured to evaluate relationships with pool characteristics and to estimate long-term exposure levels. Questionnaires were available from 624 pool workers and 38 swimming facilities. Chloramine levels were measured by area sampling over 2-h periods and analysed using ion chromatography. Work-related and general respiratory symptoms, and symptoms indicative of atopy and bronchial hyperresponsiveness were considered. Respiratory symptom prevalence among pool workers was compared with symptoms in a Dutch population sample. Chloramine levels were modelled with regression analysis. This model was used to estimate long-term average chloramine levels for each pool studied. Employees with higher exposure reported upper respiratory symptoms with greater frequency. Upper respiratory symptoms were statistically significantly associated with cumulative chloramine levels (odds ratio (OR) >1.4 for hoarseness, lost voice, sinusitis). General respiratory symptoms were significantly elevated compared with a Dutch population sample (OR ranged 1.4-7.2). An excess risk for respiratory symptoms indicative of asthma was observed in swimming pool employees. Aggravation of existing respiratory disease or interactions between irritants and allergen exposures are the most likely explanations for the observed associations.

Adolescent↗
PubMedDate not supplied

Development and validation of a gas chromatography/mass spectrometry procedure for confirmation of para-toluenesulfonamide in edible fish fillet tissue.

Chloramine-T is a disinfectant being developed as a treatment for bacterial gill disease in cultured fish. As part of the drug approval process, a method is required for the confirmation of chloramine-T residues in edible fish tissue. The marker residue that will be used to determine the depletion of chloramine-T residues from the edible tissue of treated fish is para-toluenesulfonamide (p-TSA), a metabolite of chloramine-T. The development and validation of a procedure for the confirmation of p-TSA is described. Homogenized fish tissue is dried by mixing with anhydrous sodium sulfate, and the mixture is extracted with methylene chloride. The extract is passed through a silica gel solid-phase extraction column, from which p-TSA is subsequently eluted with acetonitrile. The acetonitrile extract is evaporated, and the oily residue is dissolved in hexane. The hexane solution is shaken with fresh acetonitrile. The acetonitrile solution is evaporated and the residue is redissolved in dilute potassium hydroxide solution. The aqueous solution is extracted with methylene chloride to further remove more of the fat co-extractive. The aqueous solution is reacted with pentafluorobenzyl bromide in presence of tetrabutylammonium hydrogensulfate. The resulting di-(pentafluorobenzyl) derivative of p-TSA is analyzed by gas chromatography/mass spectrometry. This method permits the confirmation of p-TSA in edible fish tissue at 20 ppb.

Animals↗