Nash Reagent Research Articles

IDENTIFICATION OF FORMALIN CONTENT IN ANCHOVY SALTED FISH SOLD IN SEVERAL TRADITIONAL MARKETS IN BANDUNG CITY

Formalin is one of the preservatives that are dangerous when added to food. However, its use is still widely carried out by irresponsible producers, one of which is in anchovies. This study aims to analyze the presence or absence of formalin content in anchovy salted fish sold in several traditional markets in Bandung. The formalin test method was carried out qualitatively and quantitatively using a nash reagent and a spectrophotometer UV-Vis. The results of research on anchovy salted fish samples from Gedebage Market, Caringin Market, Simpang Dago Market, and Kosambi Market found the presence of formalin in all samples with the highest content in anchovy samples obtained from Gedebage Market, which was 7,14 mg/l.

A sensitive paper-based vapor-test kit for instant formalin detection in food products

A colorimetric sensing method based on a paper-based vapor-test kit was successfully developed for the selective and sensitive real-time monitoring of formalin in food samples. The device was specifically designed to efficiently extract and detect formalin simultaneously. A microcentrifuge tube was used as the sample solution container, with the inner cap serving as the reaction and detection zone. Formalin was converted into gaseous formaldehyde through controlled heating, which was then extracted and collected on a filter paper coated with Nash's reagent. The color change on paper was used for formalin quantification using a smartphone for detection and image analysis. Under optimal conditions, our method provided a linear range of 0.5–75 mg L−1 with a detection limit of 0.11 mg L−1. This method effectively determined formalin in fresh food and vegetable samples, with recoveries ranging from 92 to 111%, demonstrating comparable accuracy to the standard method for practical food quality control and safety.

Hybrid materials based on deep eutectic solvents for the preconcentration of formaldehyde by SPME in coffee beverages

Coffee is one of the most widely consumed beverages. It can be prepared from green or roasted beans or from instant coffee. Unfortunately, in addition to the aroma obtained in the coffee roasting process, among others, formaldehyde can be produced. In this study, thin-film solid-phase microextraction was used to preconcentrate trace amounts of formaldehyde in different types of coffee with different roasting levels. For this purpose, 18 hybrid materials based on deep eutectic solvents were synthesized and tested as sorbents in thin-film solid-phase microextraction. The coffee samples were brewed, and then formaldehyde present in them was derivatized using the Nash reagent. The sample preparation procedure was optimized for selected DES-based sorbent using a central composite design method and validated. Formaldehyde was determined in almost all samples of second-crack coffee (roasted at 240 °C) at 0.17–0.75 ng mL−1 and in darker-colored instant coffees at 0.18–0.54 ng mL−1.

ANALISIS KANDUNGAN FORMALIN PADA MIE BASAH DI PASAR BERINGHARJO DAN PASAR KOTA GEDE YOGYAKARTA

Formalin is an additive that is prohibited in food but is still used in wet noodles to create long-lasting products so that they can be distributed in various regions with the same quality. The study aims to determine the presence and content of formaldehyde in wet noodles sold at Beringharjo Market and Yogyakarta Kotagede Market. The method used a qualitative test with Nash reagent and a quantitative test with UV-Vis spectrophotometry. Data analysis uses all information and is explained descriptively. The results of this study were the qualitative test of 6 samples and 2 samples of wet noodles were positive for formalin and the quantitative test showed that the formalin level in sample A was 9.31 ± 0.031 mg/kg and sample B was 6.10 ± 0.031 mg/kg. Based on this study, it can be concluded that the formalin content in the wet noodle samples is not in accordance with SNI 2987, which states that formalin cannot be contained in food. Keywords: Formalin, Wet Noodles, UV-Vis Spectrophotometry

Analysis of Borax and Formalin in Wet Noodles From Sidoarjo Traditional Market

Wet noodles are a type of noodle with a fairly high water content (35-52%), so it is easy to spoil if stored for more than 12 hours at room temperature. Misuse of the addition of borax and formalin by irresponsible food manufacturers, aims to make wet noodles last longer. This study aims to determine whether the wet noodles sold in several traditional markets in Sidoarjo contain harmful ingredients borax and formaldehyde. The research design in this study began with organoleptic observations on several wet noodles found in several traditional markets in Sidoarjo Regency, followed by a borax test using a borax rapid test kit and a formalin test with UV Vis spectrophotometry and Nash reagent. Based on the test results, it can be concluded that organoleptic observations showed that there were 3 samples of wet noodles with a floury smell and 5 samples with a sour smell, in terms of texture all samples showed a soft and easily broken texture while in terms of color there were 5 samples that were pale yellow and 3 samples were bone white. Based on the results of the qualitative test of borax, all samples of wet noodles were negative for borax and based on the results of the quantitative test of formalin with UV Vis spectrophotometry, showed a negative result of formalin.

Deep Eutectic Solvent-Based Coating Sorbent for Preconcentration of Formaldehyde by Thin-Film Solid-Phase Microextraction Technique

A thin-film solid-phase microextraction method with a sorbent composed of a deep eutectic solvent was developed for the preconcentration of formaldehyde from river and lake water samples. Four new deep eutectic solvents (DESs) were synthesized, each in molar ratios 1:1, 1:2, and 1:3. Among prepared compounds, the greatest efficiency in the proposed method of preconcentration of formaldehyde derivatized with Nash reagent was demonstrated by DES-3 consisting of benzyldimethylhexadecylammonium chloride and lauric acid, in a molar ratio of 1:3. For the proposed method, the parameters affecting the extraction efficiency of formaldehyde were optimized (including the choice of DES-based sorbent and desorption solvent as well as the sample volume and pH, the salting-out effect, the extraction time, and the desorption time). Under optimal conditions, the proposed method achieved good precision between 3.3% (for single sorbent) and 4.8% (for sorbent-to-sorbent) as well as good recovery ranging from 78.0 to 99.1%. The limits of detection and quantitation were 0.15 ng mL−1 and 0.50 ng mL−1, respectively. The enrichment factor was equal to 178. The developed method was successfully applied to determine formaldehyde in environmental water samples.

IDENTIFICATION OF FORMALDEHYDE IN UNBRANDED WET NOODLES AT TRADITIONAL MARKETS OF TAMBUN SELATAN USING TEST KIT METHODS AND UV-VIS SPECTROPHOTOMETRY

Introduction: Wet noodles are flour-based foods that are widely consumed by the community because of their easy processing. The high water content in wet noodles makes the noodles not last long. In fact, there is still a preservative in wet noodles that is not used, namely formaldehyde. The purpose of this study was to determine whether there was formaldehyde in unbranded wet noodles in the Traditional Market of South Tambun District and to determine the level of formaldehyde in unbranded noodles in the Traditional Market of South Tambun District.
 Method: This research was conducted at the STIKes Mitra Keluarga laboratory. The type of research used is descriptive. There are 7 samples taken from 4 different markets. The sample was tested using a formaldehyde test kit and resulted in 6 positive formaldehyde samples. According to SNI, formaldehyde should not be in wet noodles. So that the results of the 6 samples did not meet the quality requirements of wet noodles.
 Results: Furthermore, the positive sample was determined using a UV-VIS spectrophotometer and Nash reagent. The lowest level of formaldehyde is 18.61 mg/L while the highest level is 738.45 mg/L.
 Conclusion: First, the regulation is not yet known by the producers because it is classified as traditional. Second, there is no good control from authorized institutions or officers. Third, the lack of guidance for producers

Comparison of the Formaldehyde Content in Indian Mackerel (Rastrelliger kanagurta) Fish Using High Performance Liquid Chromatography and UV-Vis Spectrophotometry

ABSTRACT Because Goa is a favorite destination for international and national tourism, there is a great demand for seafood there. Formalin (30–40% of formaldehyde, FA) can be added as a preservative to many fishery products to extend shelf life. To access the risk of exposure to FA content, Indian mackerel (Rastrelliger kanagurta) was chosen and analyzed with Nash reagent using two different techniques: high-performance liquid chromatography (HPLC) and ultraviolet-visible (UV-Vis) spectrophotometry. The study revealed FA at various levels of concentration (mg/kg). Higher exposure to FA content was found in fish and ice water from wholesale market samples using both methods. The FA content was 19.26 ± 0.84 mg/kg in fresh fish, 39.37 ± 0.93 mg/kg in wholesale market fish, and 32.95 ± 1.05 mg/kg in retail market fish using spectrophotometry, whereas it was 4.00 ± 0.15 mg/kg, 31.05 ± 0.18 mg/kg, and 31.64 ± 0.26 mg/kg in fresh fish, wholesale market, and retail market fish, respectively, using HPLC analysis.

Application of Different Methods to Determine Urease Activity in Enzyme Engineering Experiment and Production

The determination of urease activity is one of the important projects in 《Enzyme engineering experiment》 and production. In the paper, the urease activity of soybean was determined by pH increment method, titration method and Nash reagent method, and the three methods were compared. The results showed that the urease activity of the same sample measured by pH increment method, titration method and Nash reagent method was not equal in value and could not be used mutually, and the urease activity of the same sample measured by Nash reagent method was the highest. The same experimental project adopts a variety of methods to improve students ’ interest in learning, improve students’ data analysis ability, and provide a better way to cultivate applied and innovative talents.

POTENTIAL OF BLACK TEA TO REDUCE FORMALDEHYDE LEVELS IN FRESH TUNA FISH (Auxis thazard) DURING IMMERSION TIME

Saponin in black tea is predicted having potential to reduce formaldehyde level in preserved fresh tuna (Auxis thazard) using formaldehyde. This research used experimental design, post-test only control group. Variables examined were formaldehyde level, organoleptic values (eye appearance, gill appearance, color, smell, and texture), and soluble protein level. Formaldehyde level was analyzed using Nash reagent by spectrophotometric method. Organoleptic value was conducted using questionnaire by 16 panelists. Soluble protein level was analyzed using Lowry reagent by spectrophotometry. Result showed significant difference between formaldehyde level in control and treatment gorup, but did not significantly difference between formaldehyde level that was immersed in water and black tea solution. Soluble protein level showed no significant difference between samples. There were significant differences in appearance and eye color, while there were no differences in gill appearance, smell and texture. The best treatment was samples immersed in black tea 1,5% for 90 minutes with average levels of formaldehyde 55,76 ug/g, soluble protein content of 0,042 mg/g, eyes appearance 1,59 (slightly white orange), the appearance of gills 2,41 (less crimson), 2,78 body color appearance (slightly orange white), the smell of 2,63 (pungent), the texture of 1,69 (slightly soft).
 Keyword : black tea, formaldehyde, saponin

PENGARUH BEBERAPA PERLAKUAN TERHADAP PENGURANGAN KADAR FORMALIN PADA IKAN YANG DITENTUKAN SECARA SPEKTROFOTOMETRI

The case of how handling the fresh fish which used the dangerous chemical material (formaldehyde) is still found in society, so that is why it is necesarry to find the safety way to handle the fresh fish in. It has been held the research about the influence of on the effect of some treatment in reduction the formaldehyde level on fish determined by spectrophotometry UV-Visible at wavelength 412 nm and 40°C. In the preliminary research the fish is soaked in formaldehyde liquid (100 mg/mL) for 24 hours, then washed, soaked and boiled. Then, the filtrate is reacted with Nash reagent. The yellow color which has formed was measured at λ 412 nm. The result shows there is the reduction of formaldehyde level in the sample about 43.9 % after washing, 33.3 % after soaking, 53.8 % after boiling. After that, the fish that was spread in the market which suspected containing the formaldehyde then washed, soaked and boiled. The result shows there is the reduction of formalin level in sample 1 about 22,7 % after washing, 17.0% after soaking, and 96.1 % after boiling. While in sample 2, 41.8 % after washing, 56.2 % after soaking, and 95.4 % after boiling.

EVALUATION OF DIFFERENT COLORIMETRIC REAGENTS FOR THE DETERMINATION OF FORMALDEHYDE IN INDOOR ENVIRONMENTS

Different colorimetric reagents, the Nash reagent (acetylacetone/ammonia solution), Purpald (4-amino- 3-hydrazino-5-mercapto-1,2,4-triazole/sodium hydroxide solution) and 3-methyl-2-benzothiazolinone hydrazone (MBTH), were evaluated for the determination of formaldehyde in indoor air samples. Analytical parameters such as color stability of the product formed, sampling efficiency and reaction conditions were compared for the methodologies. Several method validation parameters were determined for the three colorimetric methods. The MBTH method showed better results and was used for the determination of formaldehydes in indoor environments.

Photodegradation of Aqueous Sodium Carbonate by KNiF<sub>3</sub> Nanoparticles

The nanoKNiF3 with its particles size of 50-70 nm was prepared by solvent-thermal method and characterized by means of XRD, TEM and IR technologies. Photocatalysed reduction of aqueous Na2CO3 was carried out by using nanoKNiF3 powders. Formic acid, formaldehyde and methyl alcohol were identified as photoproducts, and were measured in spectrophotometry using Nash reagent. It shows that nanoKNiF3 has superior photocatalytic activity. Irradiation leads to the production of electrons in the conduction band of the KNiF3 nanoparticles. It is likely that the photoproduced electrons reduce CO32- initially to HCOO-, and then to HCHO and CH3OH.

Determination Of Formaldehyde In Tofu From Ciputat Traditional Market With Colorimetry Method

Tofu, a food product made from soybean, contain water and it is very easy to overgrown microbes.Based on a survey, many products of tofu contain formaldehyde as preservative. Formaldehyde is apreservative that the use is prohibited for food because it can cause cancer in humans. The aim of thisstudy was determined concentration of formaldehyde in tofu from traditional market Ciputat usingSpectrophotometer UVI-VIS. Steam distillation was used for sample extraction process. Distillate wasreacted with Nash reagent. The equation of calibration curve is y=0,0032x – 0,0079 and correlationcoefficient of the linear regression of 0,9992. The experimental results obtained LOD value of11.1328 μg/ml, LOQ value of 37,1094 μg/mL The precision of this analytical method were lower than2% for each of the sample, while method’s accuration for tofu was 98,69% ± 0,4085%. Results ofsample analysis from Ciputat market, samples were detected containing formaldehyde. Formaldehydeconcentrations are 104,87 μg/mL, 11,21 μg/mL, 1,96 μg/mL, 190,80 μg/mL, 201,98 μg/mL, 10,47μg/mL, and 3,31 μg/mL.

Analisis Formalin dalam Sampel Ikan dan Udang Segar dari Pasar Muara Angke

The use of formalin as a food additive has been prohibited by the ministry of health as stipulated in The Indonesia Ministry of Health Regulations No.722/Menkes/Per/IV/ 88. However, in recent years the Indonesian authorities have found trace amounts of formalin as a preservative in perishable foods such as fish and shrimp. The aim of this research is to identify the use of formalin in fresh fish and shrimp samples sold in Muara Angke Market as the fresh seafood market in Jakarta. The first step of this research was formalin identification in fish and shrimp samples and continued by quantitative analysis to assure the results obtained. Qualitative determination of formalin was carried out by Schryver reagent and the quantitative determination was carried out spectrophotometrically using Nash reagent. Validation of UV-Vis spectrophotometric method for determination of formalin showed that Nash reagent was suitable to determine formalin. The limit of detection, limit of quantitation, and coefficient of variation for formalin were 0,0102 mg/L, 0,0341 mg/L, and 0,09%, respectively. Recovery of formalin in fish samples was 89,79-109,58% and shrimp samples was 82,11-97,76%. Qualitative determination in six fish samples and six shrimp samples showed negative results and the quantitative analysis confirmed that formalin was not found in the fresh fish and shrimp samples from Muara Angke Market. Keywords : fish, formalin, Nash, Schryver, shrimp, Spectrophotometry.

The Nanoparticle Photogenerated by Association of Phenothiazine Nucleus to Poly(ethylene glycol) Protects Photodamage in Mitochondrial Membrane Unsaturated Lipids

This study investigated the hypothesis that human term placental lipoxygenase (HTPLO) and soybean lipoxygenase (SLO) are capable of mediating N-demethylation of selected phenothiazines and insecticides in the presence of linoleic acid (LA).In addition to being LA dependent, the N-demethylation reaction mediated by HTPLO and SLO was limited by incubation time, pH of the medium, concentration of the enzyme and the substrate. Using Nash reagent to monitor formaldehyde production, the specific activity for LA-dependent N-demethylation of chlorpromazine, a model phenothiazine, was determined to be 1.7±0.3 nmoles/min/mg HTPLO. Besides chlorpromazine, N-demethylation of promazine, promethazine and trimeprazine was also observed. The insecticide, aminocarb, displayed a specific activity of 2.2±0.3 nmoles/min/mg HTPLO for N-demethylation. Other insecticides, namely chlordimeform, dicrotophos and zectran, were oxidized in a similar manner. As compared with HTPLO, the rates of N-demethylation of phenothiazines and insecticides mediated by SLO were higher. Classical inhibitors of lipoxygenase, as well as antioxidants and free radical scavengers, caused a dose-dependent reduction in the production of formaldehyde from chlorpromazine and aminocarb by HTPLO. These results clearly demonstrate the ability of polyunsaturated free fatty acids to support N-demethylation of xenobiotics via the lipoxygenase pathway.

Graphite furnace atomic absorption spectrometry as a routine method for the quantification of beryllium in blood and serum.

BackgroundA routine method for the quantification of beryllium in biological fluids is essential for the development of a chelation therapy for Chronic Beryllium Disease (CBD). We describe a procedure for the direct determination of beryllium in undigested micro quantities of human blood and serum using graphite furnace atomic absorption spectrometry. Blood and serum samples are prepared respectively by a simple 8-fold and 5-fold dilution with a Nash Reagent. Three experimental setups are compared: using no modifier, using magnesium nitrate and using palladium/citric acid as chemical modifiers.ResultsIn serum, both modifiers did not improve the method sensitivity, the optimal pyrolysis and atomization temperatures are 1000°C and 2900°C, respectively. In blood, 6 μg of magnesium nitrate was found to improve the method sensitivity. The optimal pyrolysis and atomization temperatures were 800°C and 2800°C respectively.ConclusionIn serum, the method detection limit was 2 ng l-1, the characteristic mass was 0.22 (± 0.07) pg and the accuracy ranged from 95 to 100%. In blood, the detection limit was 7 ng l-1, the characteristic mass was 0.20 (± 0.02) pg and the accuracy ranged from 99 to 101%.

Cytochrome b5 Inhibits Electron Transfer from NADPH-Cytochrome P450 Reductase to Ferric Cytochrome P450 2B4

Experiments demonstrating that cytochrome (cyt) b5 inhibits the activity of cytochrome P450 2B4 (cyt P450 2B4) at higher concentrations suggested that cyt b5 was occupying the cyt P450 reductase-binding site on cyt P450 2B4 and preventing the reduction of ferric cyt P450 (Zhang, H., Im, S.-C., and Waskell, L. (2007) J. Biol. Chem. 282, 29766-29776). In this work experiments were undertaken with manganese-containing cyt b5 (Mn-cyt b5) to test this hypothesis. Because Mn-cyt b5 does not undergo oxidation state changes under our experimental conditions, interpretation of the experimental results was unambiguous. The rate of electron transfer from cyt P450 reductase to ferric cyt P450 2B4 was decreased by Mn-cyt b5 in a concentration-dependent manner. Moreover, reduction of cyt P450 2B4 by cyt P450 reductase was incomplete in the presence of Mn-cyt b5. At a Mn-cyt b(5):cyt P450 2B4:cyt P450 reductase molar ratio of 5:1:1, the rate of reduction of ferric cyt P450 was decreased by 10-fold, and only 30% of the cyt P450 was reduced, whereas 70% remained oxidized. It could be demonstrated that Mn-cyt b5 had its effect by acting on cyt P450, not the reductase, because the reduction of cyt c by cyt P450 reductase in the presence of Mn-cyt b5 was not effected. Furthermore, under steady-state conditions in the cyt P450 reconstituted system, Mn-cyt b5, which lacks the ability to reduce oxyferrous cyt P450 2B4, was unable to stimulate the activity of cyt P450. Mn-cyt b5 only inhibited the cyt P450 2B4 activity. In conjunction with site-directed mutagenesis studies and experiments that strongly suggested that cyt b5 competed with cyt P450 reductase for binding to cyt P450, the current investigation demonstrates unequivocally that cyt b5 inhibits the activity of cyt P450 2B4 by preventing cyt P450 reductase from binding to cyt P450, a prerequisite for electron transfer from cyt P450 reductase to cyt P450 and catalysis.

A fluorescent dosimeter for formaldehyde determination using the Nash reagent in silica gel beads

Based on the Nash reagent embedded in silica gel beads as a recognition element, a fluorescent dosimeter for formaldehyde determination is established. The system can act as a fluorescent off–on switch for the qualitative detection of formaldehyde. The fluorescence emission of the Nash reagent-loaded silica gel beads is “switches off” (or very low) before exposure to formaldehyde, while fluorescence can be switched on when the beads are contacted with formaldehyde. The slope of fluorescence time scan spectra changes with formaldehyde concentration, which constitutes the basis of quantitative determination of formaldehyde concentration. The formaldehyde can also be semi-quantitatively measured in a naked-eye-detectable fashion. No response of this dosimeter to primary alcohols, ketones and other common substances was observed. The dosimeter is sensitive, inexpensive, a disposable, and simple in operation.

Role of Protein Kinase C-mediated Protein Phosphorylation in Mitochondrial Translocation of Mouse CYP1A1, Which Contains a Non-canonical Targeting Signal

A large number of mitochondrial proteins lack canonical mitochondrial-targeting signals. The bimodal transport of cytochromes P450 (CYPs) to endoplasmic reticulum and mitochondria (MT), reported previously by us, likely represents one mode of non-canonical protein targeting to MT. Herein, we have studied the mechanism of mouse MT-CYP1A1 targeting to gain insight into the regulatory features and evolutionary conservation of bimodal targeting mechanism. Mouse MT-CYP1A1 consists of two NH2-terminal-truncated molecular species, +91A1 and +331A1. Mutations Pro-2 --> Leu and Tyr-5 --> Leu, which increase the signal recognition particle (SRP) binding, diminished MT targeting of the protein in intact cells. By contrast, mutations Leu-7 --> Asn and Leu-17 --> Asn, which decreased SRP-binding affinity, enhanced MT targeting, thus suggesting that SRP binding is an important regulatory step that modulates bimodal targeting. Protein kinase C (PKC)-mediated phosphorylation of nascent chains at Thr-35 vastly decreased affinity for SRP binding suggesting an important regulatory step. In support of these results, COS cell transfection experiments show that phosphomimetic mutation Thr-35 --> Asp or induced cellular PKC caused increased CYP1A1 targeting to MT and correspondingly lower levels to the endoplasmic reticulum. Results suggest evolutionary conservation of chimeric signals and bimodal targeting of CYP1A1 in different species. The mouse MT-CYP1A1 is an extrinsic membrane protein, which exhibited high FDX1 plus FDXR-mediated N-demethylation of a number of tricyclic antidepressants, pain killers, anti-psychotics, and narcotics that are poor substrates for microsomal CYP1A1.