Formalin pigment artifact deposition in autopsy tissue: predisposing factors, patterns of distribution and methods for removal.

Formalin pigment deposition is a known artifact of autopsy histology, often anecdotally associated with decomposition of bodies. However, there is minimal data within the forensic literature demonstrating an association between formalin pigment deposition and length of postmortem interval. Furthermore, there is minimal data concerning other predisposing factors and patterns of distribution of formalin pigment deposition. In this study, we compare the amount and patterns of formalin deposition on histology slides from three categories of death: 1) decomposed bodies, 2) critically ill at time of death, and 3) sudden cardiac death. We also compare the effectiveness of two relatively simple histology laboratory methods to remove formalin pigment deposition from histology slides. Amongst the three categories of death, formalin deposition was highest in the decomposed category, second highest in the critically ill category, and lowest in the sudden cardiac death category. The organs most severely affected by formalin deposition were liver/spleen/pancreas and kidneys, and the organs least affected were brain and lung. Formalin pigment deposition correlated with length of postmortem interval. Histologic patterns of formalin deposition included the endothelial lining of vessels, perinuclear compartment of neurons and myocytes, and the basal epithelial compartment of renal tubular epithelial cells. The alcoholic ammonium hydroxide method (AAH) was slightly more effective than the alkylphenol ethoxylate (APE) method for removing formalin pigment, though both methods were effective. Because formalin pigment is strongly refractile under polarized light, a polarization filter can also be useful for distinguishing formalin pigment from other pigments.

Determination of the lowest concentrations of aldehyde fixatives for completely fixing various cellular structures by real-time imaging and quantification.

The effectiveness of fixatives for fixing biological specimens has long been widely investigated. However, the lowest concentrations of fixatives needed to completely fix whole cells or various cellular structures remain unclear. Using real-time imaging and quantification, we determined the lowest concentrations of glutaraldehyde (0.001-0.005, ~0.005, 0.01-005, 0.01-005, and 0.01-0.1 %) and formaldehyde/paraformaldehyde (0.01-0.05, ~0.05, 0.5-1, 1-1.5, and 0.5-1 %) required to completely fix focal adhesions, cell-surface particles, stress fibers, the cell cortex, and the inner structures of human umbilical vein endothelial cells within 20 min. With prolonged fixation times (>20 min), the concentration of fixative required to completely fix these structures will shift to even lower values. These data may help us understand and optimize fixation protocols and understand the potential effects of the small quantities of endogenously generated aldehydes in human cells. We also determined the lowest concentration of glutaraldehyde (0.5 %) and formaldehyde/paraformaldehyde (2 %) required to induce cell blebbing. We found that the average number and size of the fixation-induced blebs per cell were dependent on both fixative concentration and cell spread area, but were independent of temperature. These data provide important information for understanding cell blebbing, and may help optimize the vesiculation-based technique used to isolate plasma membrane by suggesting ways of controlling the number or size of fixation-induced cell blebs.

Cytogenetic and immunological effects associated with occupational formaldehyde exposure.

Formaldehyde (FA) is a widely used industrial chemical for which exposure is associated with nasopharyngeal and sinonasal cancer. Based on sufficient evidence of carcinogenicity from human investigations, supporting studies on mechanisms underlying carcinogenesis, and experimental evidence in animals, FA status was recently revised and reclassified as a human carcinogen. The highest level of exposure to FA occurs in occupational settings. Although several studies reported FA ability to induce genotoxic responses in exposed workers, not all findings were conclusive. In addition, published studies on the immunological effects of FA indicate that this compound may be able to modulate immune responses, although data in exposed subjects are still preliminary. In this study a group of pathology anatomy workers exposed to FA was evaluated for cytogenetic and immunological parameters. A control group with similar sociodemographic characteristics and without known occupational exposure to FA was also included. Genotoxicity was evaluated by means of micronucleus (MN) test, sister chromatid exchanges (SCE), and T-cell receptor (TCR) mutation assay. Percentages of different lymphocyte subpopulations were selected as immunotoxic biomarkers. The mean level of FA environmental exposure was 0.36 ± 0.03 ppm. MN and SCE frequencies were significantly increased in the exposed group. A significant decrease of the percentage of B cells in the exposed group was also found. Data obtained in this study indicate that genotoxic and immunotoxic increased risk due to FA occupational exposure cannot be excluded. Implementation of effective control measures along with hazard prevention campaigns may be crucial to decrease the risk.

Comparison of fixatives and fixation time for PCR detection of Mycobacterium in zebrafish Danio rerio .

Mycobacteriosis is a common disease of laboratory zebrafish Danio rerio. Different infection patterns occur in zebrafish depending on mycobacterial species. Mycobacterium marinum and M. haemophilum produce virulent infections associated with high mortality, whereas M. chelonae is more widespread and is not associated with high mortality. Identification of mycobacterial infections to the species level provides important information for making management decisions. Observation of acid-fast bacilli in histological sections or tissue imprints is the most common diagnostic method for mycobacteriosis in fish, but only allows for diagnosis to the genus level. Mycobacterial culture followed by molecular or biochemical identification is the traditional approach, but DNA of diagnostic value can also be retrieved from paraffin blocks. Here we investigated the type of fixative, time in fixative before processing, species of mycobacteria, and severity of infection as parameters to determine whether the hsp gene PCR assay (primer set HS5F/hsp667R) could detect and amplify mycobacterial DNA from paraffin-embedded zebrafish. Whole zebrafish were experimentally infected with either M. chelonae or M. marinum, and then preserved in 10% neutral buffered formalin or Dietrich's fixative for 3, 7, 21, and 45 d. Subsequently, fish were evaluated by hematoxylin and eosin and Fite's acid-fast stains to detect mycobacteria within granulomatous lesions. The PCR assay was quite effective and obtained PCR product from 75 and 88% of the M. chelonae- and M. marinum-infected fish, respectively. Fixative type, time in fixative, and mycobacterial species showed no statistical relationship with the efficacy of the PCR test.

[Experimental value of formaldehyde exposure to preserve anatomical findings]. / Valutazione sperimentale dell'esposizione a formaldeide durante il suo utilizzo per la conservazione di reperti anatomici.

Formaldehyde, already classified as potentially carcinogen and recently as "human carcinogen" by IARC, is generally used for fixing and preserving anatomical findings. This reason causes a problem of professional exposure for the operators who use the formaldehyde for this purpose. In this work we present the results of the periodical monitoring which is done for the determination of the exposure at formaldehyde in operating theatres and surgeries, where the operator fill the special container with the anatomical findings andformaldehyde for following tests. The measurements have been done using an instrument that continuously measure the concentration of formaldehyde, based on the infrared spectrometry, in 54 rooms which are operating theatres or surgeries in 9 public hospitals in Campania (Italy). The results show that the long-term exposure limits are not exceeded and that the average of the highest values of concentration obtained during its use was 0.15 +/- 0.04 ppm, that is below the limits. It is important to point out that such a limit was never exceeded during every single measurement. Finally, analyzing statistically the data, we can infer that the probability of exceeding the short-term limit is less than 0.1%, when formaldehyde is used for the purposes mentioned above.

Evaluation of formaldehyde exposure among gross dissection after modified embalming solution and health assessment.

Mainly embalming fixative contains formaldehyde which is classified as a carcinogen. People who work with cadavers have been at higher risk of cancer after formaldehyde exposure. We have formulated a less-formalin fixative (contained 3.6% formaldehyde,23.8% ethanol, 15% glycerin, and 0.2% phenol in the water) for preserving cadavers. Therefore, the objective of the present study was to evaluate the level of atmospheric formaldehyde indoors and the breathing exposure of medical students during dissection classes. We also analyzed the pulmonary parameters and effects of formaldehyde. The levels of atmospheric formaldehyde indoors and personal breathing exposure were sampled during anatomy dissection classes (musculoskeletal system, respiratory system, and abdominopelvic organ system) using sorbent tubes with air sampling pumps. Samples were then analyzed using Gas Chromatography with Flame Ionization Detector (GC-FID). The mean level of formaldehyde indoor air among the three classes was 0.518 ± 0.156 ppm whereas the formaldehyde level in the personal breathing zone was 0.956±0.408 ppm, which exceeded the recommended exposure standards of international agencies, including NIOSH agency and PEL of Thailand legislation. The laboratory had high humidity, high room temperature, and poor air ventilation. There was a significant difference in FVC, FEV1, and PEF (p < 0.05) between the sexes of students. Comparison pulmonary parameters between students and instructors showed that all parameters of the pulmonary function test had no significant differences. General fatigue and burnings of eyes and nose associated with strong odor were the most common symptoms reported during the dissection classes. The modified embalming fixative was used less formalin with ethanol-glycerin mixture, and it was suitable for the study of medical students, with few side effects of respiratory problems. However, the modified exhaust ventilation with local table-exhaust ventilation and heating-ventilation-air conditioning system performance were urgent issues for reducing levels of formaldehyde indoor air in the dissection room.

Fluorescence-based fixative and vital staining of lipid droplets in Caenorhabditis elegans reveal fat stores using microscopy and flow cytometry approaches.

The proportions of body fat and fat-free mass are determining factors of adiposity-associated diseases. Work in Caenorhabditis elegans has revealed evolutionarily conserved pathways of fat metabolism. Nevertheless, analysis of body composition and fat distribution in the nematodes has only been partially unraveled because of methodological difficulties. We characterized metabolic C. elegans mutants by using novel and feasible BODIPY 493/503-based fat staining and flow cytometry approaches. Fixative as well as vital BODIPY staining procedures visualize major fat stores, preserve native lipid droplet morphology, and allow quantification of fat content per body volume of individual worms. Colocalization studies using coherent anti-Stokes Raman scattering microscopy, Raman microspectroscopy, and imaging of lysosome-related organelles as well as biochemical measurement confirm our approaches. We found that the fat-to-volume ratio of dietary restriction, TGF-ß, and germline mutants are specific for each strain. In contrast, the proportion of fat-free mass is constant between the mutants, although their volumes differ by a factor of 3. Our approaches enable sensitive, accurate, and high-throughput assessment of adiposity in large C. elegans populations at a single-worm level.

Formaldehyde exposure of medical students and instructors and clinical symptoms during gross anatomy laboratory in Thammasat University.

To study formaldehyde concentrations in the breathing zone and symptoms induced by gaseous formaldehyde exposure of medical students and instructors during gross anatomy laboratory at faculty of Medicine, Thammasat university. Formaldehyde concentrations in the indoor air and breathing zone of medical students were measured during the cadaver dissection. Formaldehyde concentrations in the indoor air and in the breathing zone were ranged from 0.401 to 0.581 ppm (mean 0.491 +/- 0.090) and from 0.472 to 0.848 ppm (mean 0.660 +/- 0.188) respectively. The mean of formaldehyde concentrations in the breathing zone of medical students and instructors was significantly higher than the mean of formaldehyde concentration in indoor air (p < 0.05). The most symptoms were general fatigue (82.7-87.8%), burning eyes (66.2-85.0%) and burning nose (62.5-81.1%). There was no statistically significant difference in burning eye symptom between contact lenses users and no contact lenses users (p > 0.05). Even though formaldehyde concentrations were relatively low, medical students, instructors and cadaver related workers should wear personal protective devices to reduce the effect of gaseous formaldehyde exposure during gross anatomy laboratory or contact cadaver.

Safety assessment of antioxidants and color fixatives for the Korean population using dietary intake monitoring.

Food additives such as antioxidants and color fixatives are substances used in food intentionally for technical effect, such as decolorizing or intensifying the color of food. Based on the necessity of re-evaluating food additives for safety and to improve consumer perception, we conducted safety assessments for food additives according to the Risk Assessment Guidelines of the Korean Ministry of Food and Drug Safety. These safety assessments evaluated new risk information based on toxicology data and estimates of dietary intake exposures to food additives in comparison with the acceptable daily intake (ADI). Estimated daily intakes (EDI) of food additives were calculated using food consumption data for the Korean population derived from the Korea National Health and Nutrition Examination Survey and monitoring data based on the analysis of food additives in food products. Unlike contaminants, antioxidants and color fixatives are purposely added as food additives, and they are largely consumed in processed foods. Therefore, EDI was compared with ADI to investigate the likelihood of potentially hazardous effects in humans. The risk likelihoods of food additives, evaluated by comparing the EDI with the ADI, were less than 2% in the total population. Thus, exposure levels to antioxidants and color fixatives do not exceed the ADI. Based on the safety assessments conducted in this study, we estimate exposure to food additives to be within safe limits for all population groups.

[Vertical distribution of formaldehyde concentration and simulated temperature and wind velocity from computational fluid dynamics in a gross anatomy laboratory].

Cadavers for gross anatomy laboratories are typically embalmed in formaldehyde. Thus, medical students and instructors are exposed to formaldehyde vapors emitted from cadavers during dissection. In an attempt to improve the dissection environment, we examined indoor formaldehyde concentrations in a gross anatomy laboratory. Air samples were taken from 20, 110, 160, and 230 cm above the floor between dissection beds to represent areas near the floor, in the breathing zone of sitting students, in the breathing zone of standing students, and near the ceiling, respectively. Formaldehyde vapors were thoroughly diffused from the floor to the ceiling, suggesting that medical students are exposed to similar concentrations of formaldehyde based on distance from the floor. Computational fluid dynamics showed that cadavers are warmed by overhead fluorescent lights and the body heat of anatomy students, and indicated that the diffusion of formaldehyde vapors is increased by lighting and the body temperature of students. Computational fluid dynamics showed that gentle convection from anatomy students and cadavers carry formaldehyde vapors upward; downward flow near admission ports diffuse formaldehyde vapors from the ceiling to the floor in the anatomy laboratory.

Subjective symptoms of medical students exposed to formaldehyde during a gross anatomy dissection course.

The purpose of this study is to investigate the safety of and to try to find the best plan to cope with exposure to FA for students during a gross anatomy dissection course. The FA exposure level and subjective symptoms was estimated. The relationship between exposure to FA and subjective symptoms of irritation were discussed for times; before, in the beginning period, in the middle period, and upon completion of the Anatomy Dissection Course. The geometric means of FA concentration were 32.7 micrograms/m3 (before), 891.3 micrograms/m3 (beginning), 763.3 micrograms/m3 (middle), and 238.9 micrograms/m3 (completion), respectively. Among them, FA-related symptoms were observed in 61.1 percent; 28.0 percent fell strong stress during the course, and 27.4 percent complained that their normal life situation was affected. Our results indicate that such subjective symptoms during the anatomy dissection course were related to the period spent in the anatomy dissection room. Our study suggests that shortening the time of each anatomy dissection practical class and reduction of the number of cadaver tables could help to reduce symptoms.

Monitoring losses of copper based wood preservatives in the Thames estuary.

Field trials were conducted at two sites in the Thames estuary to monitor losses of copper, chromium and arsenic from wood preservative treated timbers of varying sizes and treatment regimes. Results indicated that leaching tests conducted under standard laboratory conditions might overestimate losses compared to losses resulting from real environmental exposures. Amine copper treated wood was noted to leach higher levels of copper compared to chromated copper arsenate treated wood, and was therefore considered an inappropriate replacement biocide for fresh and marine construction purposes on this basis. Increases in copper concentrations in the outer sections of amine copper treated posts may have represented re-distribution of this component in this timber. No accumulation of metals was found in sediments surrounding field trial posts.

Formaldehyde exposure in a gross anatomy laboratory--personal exposure level is higher than indoor concentration.

GOAL, SCOPE AND BACKGROUND: Cadavers for gross anatomy laboratories are usually prepared by using embalming fluid which contains formaldehyde (FA) as a principal component. During the process of dissection, FA vapors are emitted from the cadavers, resulting in the exposure of medical students and their instructors to elevated levels of FA in the laboratory. The American Conference of Governmental Industrial Hygienists (ACGIH) has set a ceiling limit for FA at 0.3 ppm. In Japan, the Ministry of Health, Labour and Welfare has set an air quality guideline defining two limit values for environmental exposure to FA: 0.08 ppm as an average for general workplaces and 0.25 ppm for specific workplaces such as an FA factory. Although there are many reports on indoor FA concentrations in gross anatomy laboratories, only a few reports have described personal FA exposure levels. The purpose of the present study was to clarify personal exposure levels as well as indoor FA concentrations in our laboratory in order to investigate the relationship between them. METHODS: The gross anatomy laboratory was evaluated in the 4th, 10th and 18th sessions of 20 laboratory sessions in total over a period of 10 weeks. Air samples were collected using a diffusive sampling device for organic carbonyl compounds. Area samples were taken in the center and four corners of the laboratory during the entire time of each session (4-6 hours). Personal samples were collected from instructors and students using a sampling device pinned on each person's lapel, and they were 1.1 to 6 hours in duration. Analysis was carried out using high performance liquid chromatography. RESULTS AND DISCUSSION: Room averages of FA concentrations were 0.45, 0.38 and 0.68 ppm for the 4th, 10th and 18th sessions, respectively, ranging from 0.23 to 1.03 ppm. These levels were comparable to or relatively lower than the levels reported previously, but were still higher than the guideline limit for specific workplaces in Japan and the ACGIH ceiling limit. The indoor FA concentrations varied depending on the contents of laboratory sessions and seemed to increase when body cavity or deep structures were being dissected. In all sessions but the 4th, FA levels at the center of the room were higher than those in the corners. This might be related to the arrangement of air supply diffusers and return grills. However, it cannot be ruled out that FA levels in the corners were lowered by leakage of FA through the doors and windows. Average personal exposure levels were 0.80, 0.45 and 0.51 ppm for instructors and 1.02, 1.08 and 0.89 ppm for students for the 4th, 10th and 18th session, respectively. The exposure levels of students were significantly higher than the mean indoor FA concentrations in the 4th and 10th sessions, and the same tendency was also observed in the 18th session. The personal exposure level of instructors was also significantly higher than the indoor FA level in the 4th session, while they were almost the same in the 10th and 18th sessions. Differences in behavior during the sessions might reflect the differential personal exposure levels between students and instructors. CONCLUSION: The present study revealed that, if a person is close to the cadavers during the gross anatomy laboratory, his/her personal exposure level is possibly 2 to 3-fold higher than the mean indoor FA concentration. This should be considered in the risk assessment of FA in gross anatomy laboratories. RECOMMENDATION AND OUTLOOK: If the risk of FA in gross anatomy laboratories is assessed based on the indoor FA levels, the possibility that personal exposure levels are 2 to 3-fold higher than the mean indoor FA level should be taken into account. Otherwise, the risk should be assessed based on the personal exposure levels. However, it is hard to measure everyone's exposure level. Therefore, further studies are necessary to develop a method of personal exposure assessment from the indoor FA concentration.

[Occupational exposure to formaldehyde in three pathology departments]. / Esposizione professionale a formaldeide in alcuni reparti di anatomia patologica.

Although formaldehyde has recently been classified by the IARC as "carcinogenic in humans" (class 1), it is still widely used in pathology departments for the fixing and conservation of biological tissues. Its use therefore raises the question of occupational exposure. The present paper reports the results of an environmental monitoring campaign to evaluate pollution by formaldehyde in various areas of three pathology departments. Chemi-adsorbent cartridges able to adsorb airborne formaldehyde were used to detect the substance. Quantitative determination of the formaldehyde was carried out by means of liquid chromatography (HPLC). The concentrations of airborne formaldehyde in the areas monitored were fairly modest, being below the limits of indoor concentration proposed by the OSHA. In one of the three departments, however these limits were exceeded in 40% of the samples taken in the room used for the storage of containers. As yet, in spite of the recent class 1 classification by the IARC, no provisions have been made to ban the use of formaldehyde. It is therefore essential to draw up environmental monitoring programmes in order to evaluate occupational exposure and to assess the efficacy of any preventive measures adopted.

[Chemical content analysis of specimens of human head temporal portion commercially distributed for otological surgery lessons].

Specimens of the human head temporal portion are provided in the United States and distributed commercially for lessons in otological surgery via the internet. Many otologists have obtained and used these specimens in Japan. According to our chemical content analysis, these specimens were found to contain harmful substances as well as large molecule aldehydes and fatty acid methylesters, which are not or only rarely included in the human cadaveric specimens prepared in Japan. We discuss the suggested treatment of these imported specimens, how trial preparation of specimens are much better than the imported items, and the background of the rapid and wide distribution of the imported items in Japan.

The Elnady Technique: An innovative, new method for tissue preservation.

At the Faculty of Veterinary Medicine, Cairo University, there is an increasing number of students but a limited availability of animal cadavers used for dissection, and student exposure to formalin is a known hazard. In order to address these challenges, a new method for tissue preservation was developed, the "Elnady Technique." This method is a modified form of plastination, where the chemicals used are not patented, are inexpensive and locally available, and the process is performed at room temperature. The produced specimens are realistic, durable, have no offensive odor, and are dry, soft and flexible. They can be used to replace the use of animals killed for teaching basic anatomy, embryology, pathology, parasitology and forensic medicine. They have great potential to support training in clinical skills and surgery, including for clinical examination, endoscopy, surgical sutures, and obstetrics simulation.

Mosquito coil emissions and health implications.

Burning mosquito coils indoors generates smoke that can control mosquitoes effectively. This practice is currently used in numerous households in Asia, Africa, and South America. However, the smoke may contain pollutants of health concern. We conducted the present study to characterize the emissions from four common brands of mosquito coils from China and two common brands from Malaysia. We used mass balance equations to determine emission rates of fine particles (particulate matter < 2.5 microm in diameter; PM(2.5)), polycyclic aromatic hydrocarbons (PAHs), aldehydes, and ketones. Having applied these measured emission rates to predict indoor concentrations under realistic room conditions, we found that pollutant concentrations resulting from burning mosquito coils could substantially exceed health-based air quality standards or guidelines. Under the same combustion conditions, the tested Malaysian mosquito coils generated more measured pollutants than did the tested Chinese mosquito coils. We also identified a large suite of volatile organic compounds, including carcinogens and suspected carcinogens, in the coil smoke. In a set of experiments conducted in a room, we examined the size distribution of particulate matter contained in the coil smoke and found that the particles were ultrafine and fine. The findings from the present study suggest that exposure to the smoke of mosquito coils similar to the tested ones can pose significant acute and chronic health risks. For example, burning one mosquito coil would release the same amount of PM(2.5) mass as burning 75-137 cigarettes. The emission of formaldehyde from burning one coil can be as high as that released from burning 51 cigarettes.

Reduction of formaldehyde concentrations in the air and cadaveric tissues by ammonium carbonate.

The reduction of formaldehyde by ammonium carbonate was examined in cadavers and in vitro. Formaldehyde concentrations in the air (10 cm above human cadavers) and in various cadaveric tissues were measured with or without perfusion of ammonium carbonate solution into formaldehyde-fixed cadavers. Air samples were monitored using Kitagawa gas detector tubes. For measurement of formaldehyde in tissues, muscles and organs were cut into small pieces and tissue fluids were separated out by centrifugation. These specimen fluids were diluted, supplemented with 3-methyl-2-benzothiazolinone hydrazone hydrochloride and quantified by spectrophotometry. In five cadavers without ammonium carbonate treatment, the formaldehyde concentrations in the air above the thorax and in various tissue fluids were 1.2-3.0 p.p.m. and 0.15-0.53%, respectively. Arterial reperfusion of saturated ammonium carbonate solution (1.0, 1.5 or 2.0 L) into five formaldehyde-fixed cadavers successfully reduced the formaldehyde levels, both in the air (0.5-1.0 p.p.m.) and in various tissue fluids (0.012-0.36%). In vitro experiments demonstrated that formaldehyde concentrations decreased, first rapidly and then gradually, with the addition of ammonium carbonate solution into fluids containing formaldehyde. It was confirmed that formaldehyde reacted with the ammonium carbonate and was thereby changed into harmless hexamethylenetetramine. The application of ammonium carbonate solution via intravascular perfusion and, if necessary, by infusion into the thoracic and peritoneal cavities, injection into muscles and spraying on denuded tissues can be anticipated to reduce formaldehyde to satisfactorily low levels in cadaveric tissues and, consequently, in the air, which may provide safe and odorless dissecting rooms.

Setting up the criteria and credit-awarding scheme for building interior material selection to achieve better indoor air quality.

Methods, standards, and regulations that are aimed to reduce indoor air pollution from building materials are critically reviewed. These are classified as content control and emission control. Methods and standards can be found in both of these two classes. In the regulation domain, only content control is enforced in some countries and some regions, and asbestos is the only building material that is banned for building use. The controlled pollutants include heavy metals, radon, formaldehyde, and volatile organic compounds (VOCs). Emission rate control based upon environment chamber testing is very much in the nature of voluntary product labeling and ranking, and this mainly targets formaldehyde and VOC emissions. It is suggested that radon emission from building materials should be subject to similar emission rate control. A comprehensive set criteria and credit-awarding scheme that encourages the use of low-emission building material is synthesized, and how this scheme can be practiced in building design is proposed and discussed.

Detection of tannic acid at trace level in industrial wastewaters using a highly sensitive chemiluminescence method.

A novel flow injection procedure was developed for the determination of tannic acid in industrial wastewaters based on the enhancement by tannic acid of the chemiluminescence from luminol-K3Fe(CN)6-OH- system. The method has the merits of higher sensitivity, higher selectivity, wider linear range, simpler instrumentation. It is applicable for the determination of tannic acid in the range of 3.0 x 10(-10)-1.0 x 10(-7) mol/L with a detection limit of 1.0 x 10(-10) mol/L. The relative standard deviation is 2.7% for the determination of 1.0 x 10(-8) mol/L tannic acid (n = 11). The method has been successfully used to determine tannic acid at trace level in industrial wastewaters from brewery and tannery.