Analysis of melamine migration from melamine food contact articles

Ecofriendly Chromatographic Assay of Metformin Combinations; Content Uniformity Tests and Toxicity Profiling

Accurate, sensitive and green HPTLC chromatographic method was proposed for simultaneous determination of metformin, glipizide and sitagliptin in the presence of metformin potential toxic impurities melamine and cyanoguanidine. The separation was completed on silica gel HPTLC F254 plates using a mixture of ethyl acetate: methanol: ammonia: formic acid (7: 2: 0.2: 0.2, by volume) as a developing system with UV scanning for the developed bands at 235 nm. The Rf values for metformin, glipizide, sitagliptin, melamine and cyanoguanidine were 0.17, 0.84, 0.67, 0.47 and 0.75, respectively. Linear responses were observed in the ranges of 0.2-3, 0.07-1.5, 1.5-5, 0.8-4 and 0.4-2 μg/band with correlation coefficients of 0.9999, 0.9998, 0.9997, 0.9996 and 0.9998 for metformin, glipizide, sitagliptin, melamine and cyanoguanidine, respectively. The proposed method was validated as per ICH criteria with respect to linearity, accuracy, precision, specificity and robustness. The validated method was successfully applied for determination of the studied drugs in Janumet® and Engilor® tablets; also, the results were statistically compared to those obtained by the reported spectrophotometric method and no significant difference was found between them. This method permitted the accurate simultaneous determination of the studied drugs, indicating its ability to be used for routine quality control assays of these drugs.

Migration of Melamine and Its Derivatives from Melamine/Bamboo/Wheat Straw-Made Tableware Purchased from Internet Markets or Retail Shops in China

OBJECTIVES

The ecofriendly and sustainable concept of bamboo- and wheat straw-made tableware has gained attention in recent years. However, it is necessary to note that these kinds of tableware are composed of melamine (MEL)-formaldehyde resin with the addition of bamboo fibers or wheat straw. This study aims to explore the potential migration of MEL and its derivatives from the tableware and conduct a risk assessment.

METHODS

The study involved 46 bowls or cups purchased from Internet markets or retail shops in China, whose raw materials included MEL, bamboo, and wheat straw. There were four pieces of glass- or ceramic-made tableware used as the control group. Migration testing was performed according to the test conditions selected from the European Union Reference Laboratory for Food Contact Materials. Considering the realistic worst-case scenario, we measured the concentrations of MEL and its derivatives in food simulants using ultra-performance liquid chromatography-tandem mass spectrometry and estimated the exposure risks for adults and 1-year-old infants.

RESULTS

MEL and its derivatives could migrate from MEL-, bamboo-, and wheat straw-made tableware with varying concentrations. The total migration was ranked as follows: bamboo-made tableware > MEL-made tableware > wheat straw-made tableware > glass- or ceramic-made tableware (p < 0.001). The primary contributor to the total concentration for MEL- and bamboo-made tableware was MEL, whereas cyanuric acid (CYA) was the main contributor for wheat straw-made tableware. Based on the total concentration of MEL and its derivatives and the strictest TDI value, the proportions of the calculated hazard quotient ≥1 for MEL-, bamboo-, and wheat straw-made tableware in adults were 53.50%, 92.30%, and 1.90%; and the proportions in 1-year-old infants increased to 86.00%, 100.00%, and 7.40%.

CONCLUSION

The utilization of MEL-, bamboo-, and wheat straw-made tableware could be regarded as a significant source of human exposure to MEL and its derivatives. It is advisable for both adults and infants to refrain from using tableware manufactured with MEL and bamboo fiber, as it may increase the susceptibility to MEL-related diseases.

Spectrophotometric Determination of Metformin in Different Pharmaceutical Combinations with Glipizide or Sitagliptin in Presence of Toxic Impurities of Metformin

BACKGROUND

The presented quadruple divisor spectrophotometric method was able to resolve and analyze a complex quintuple drug matrix with severe overlapped spectra without previous separation or extraction steps or need of complicated apparatus like chromatographic methods and had the advantage of being green as the solvent used was water.

METHOD

Simple, sensitive and precise quadruple devisor spectrophotometric method was developed for simultaneous determination of metformin, glipizide, and sitagliptin in presence of metformin potential impurities melamine and cyanoguanidine. The proposed method was applied for analysis of metformin, glipizide, and sitagliptin in pure form and pharmaceutical formulation (tablets). The developed method was validated and met the requirements for ICH guidelines with respect to linearity, accuracy, precision, specificity and robustness.

RESULTS

A linear response was observed in the range of 2-27, 2-20, 1-20, 0.5-10, and 1-10 μg/mL for metformin, glipizide, sitagliptin, melamine and cyanoguanidine, respectively with a correlation coefficient of 0.9996 and 0.9998, 0.9997, 0.9997 and 0.9996 for metformin, glipizide, sitagliptin, melamine and cyanoguanidine, respectively.

CONCLUSION

The validated method was successfully applied for determination of the studied drugs in Janumet® and Engilor® tablets; moreover the results were statistically compared to those obtained by the reported RP-HPLC method and no significant difference was found between them; indicating the ability of proposed method to be used for routine quality control analysis of these drugs.

Protective prospects of eco-friendly synthesized selenium nanoparticles using Moringa oleifera or Moringa oleifera leaf extract against melamine induced nephrotoxicity in male rats

Nanotechnology is used in a wide range of applications, including medical therapies that precisely target disease prevention and treatment. The current study aimed firstly, to synthesize selenium nanoparticles (SeNPs) in an eco-friendly manner using Moringa oleifera leaf extract (MOLE). Secondly, to compare the protective effects of green-synthesized MOLE-SeNPs conjugate and MOLE ethanolic extract as remedies for melamine (MEL) induced nephrotoxicity in male rats. One hundred and five male Sprague Dawley rats were divided into seven groups (n = 15), including 1st control, 2nd MOLE (800 mg/kg BW), 3rd SeNPs (0.5 mg/kg BW), 4th MOLE-SeNPs (200 μg/kg BW), 5th MEL (700 mg/kg BW), 6th MEL+MOLE, and 7th MEL+MOLE SeNPs. All groups were orally gavaged day after day for 28 days. SeNPs and the colloidal SeNPs were characterized by TEM, SEM, and DLS particle size. SeNPs showed an absorption peak at a wavelength of 530 nm, spherical shape, and an average size between 3.2 and 20 nm. Colloidal SeNPs absorption spectra were recorded between 400 and 700 nm with an average size of 3.3-17 nm. MEL-induced nephropathic alterations represented by a significant increase in serum creatinine, urea, blood urea nitrogen (BUN), renal TNFα, oxidative stress-related indices, and altered the relative mRNA expression of apoptosis-related genes Bax, Caspase-3, Bcl2, Fas, and FasL. MEL-induced array of nephrotoxic morphological changes, and up-regulated immune-expression of proliferating cell nuclear antigen (PCNA) and proliferation-associated nuclear antigen Ki-67. Administration of MOLE or MOLE-SeNPs significantly reversed MEL-induced renal function impairments, oxidative stress, histological alterations, modulation in the relative mRNA expression of apoptosis-related genes, and the immune-expression of renal PCNA and Ki-67. Conclusively, the green-synthesized MOLE-SeNPs and MOLE display nephron-protective properties against MEL-induced murine nephropathy. This study is the first to report these effects which were more pronounced in the MOLE group than the green biosynthesized MOLE-SeNPs conjugate group.

HPLC and spectrophotometry methods for measuring melamine migration from melamine dishes to food simulants

Melamine is an organic-based chemical usually found as enriched white nitrogen crystals. Since melamine is used for manufacturing food dishes and containers, there are concerns about melamine migration from the dishes into foods and subsequently the human body, particularly in children.

As there are no routine techniques to measure melamine migration in food quality control laboratories in Iran, we here aimed to validate HPLC and spectrophotometry methods to measure migration of this substance. The HPLC and spectrophotometry techniques were adopted and validated. The level of melamine migration was measured in melamine ware of five brands in Iran market. Distilled water and acetic acid 3% were used as simulants. The dishes were in contact with the simulants for 90 min at 90 °C.The accuracy and precision were obtained as 94.9 and 95.3% for HPLC and 95.3% and 96.2% for spectrophotometry, respectively. Furthermore, the limit of detection (LOD) and limit of quantification (LOQ) were obtained as 145 and 435 ng/ml for HPLC, and 200 and 605 ng/ml for spectrophotometry, respectively. Our results indicated that HPLC can be a reliable method to measure low-level melamine. The spectrophotometry could also be applied as a feasible, accurate, and cost-effective method for measuring melamine in foodstuffs.•

This research has tried to adopt a method to measure melamine migration in the regions where there are no routine techniques to measure melamine migration the same as Iranian food laboratories.

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The validation results of HPLC and spectrophotometry methods showed 94.9% accuracy and 95.3% precision and 95.3 and 96.2% for spectrophotometry respectively which were reliable.

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HPLC can be a reliable method to measure low-level melamine. The spectrophotometry could also be applied as a feasible, accurate, and cost-effective method for measuring melamine in foodstuffs.

Determination of melamine contamination in chocolates containing powdered milk by high-performance liquid chromatography (HPLC)

Melamine is widely being reported as a food adulterant. Although its toxicity is currently recognized, melamine adulterations of dairy products are ongoing to apparently increase the amount of protein. The study was conducted to investigate the determination of melamine amounts in chocolates containing powdered milk. In this study, 60 samples of chocolates containing powdered milk, both imported and domestic brands, were collected. The samples were prepared by solid phase extraction (SPE) and analyzed using high-performance liquid chromatography (HPLC). According to the results, melamine was found in about 94% of imported samples and about 77% of Iranian samples. Melamine concentration in imported samples ranged from 0.032 to 2.692 mg/kg, while in Iranian ones it ranged from 0.013 to 2.600 mg/kg. The mean melamine concentrations of foreign and Iranian samples were 0.685 ± 0.68 and 0.456 ± 0.73 mg/kg, respectively. Moreover, the limit of detection (LOD) and limit of quantification (LOQ) values of melamine were 0.017 and 0.052 μg/ml, respectively. The recovery rate (R%) at fortified levels of 1-2 mg/kg was found to be 89.20-95.69% with an RSD (Relative Standard Deviation) of 1.8-2.7%. Based on the study results, melamine was present in 85% of all samples and the melamine level in one Iranian brand and one imported brand was higher than the Codex Organization standard. However, the consumption of chocolates containing these low levels of melamine does not constitute a health risk for consumers.

Food safety and quality assessment: comprehensive review and recent trends in the applications of ion mobility spectrometry (IMS)

Ion mobility spectrometry (IMS) is an analytical separation and diagnostic technique that is simple and sensitive and a rapid response and low-priced technique for detecting trace levels of chemical compounds in different matrices. Chemical agents and environmental contaminants are successfully detected by IMS and have been recently considered to employ in food safety. In addition, IMS uses stand-alone or coupled analytical diagnostic tools with chromatographic and spectroscopic methods. Scientific publications show that IMS has been applied 21% in the pharmaceutical industry, 9% in environmental studies and 13% in quality control and food safety. Nevertheless, applications of IMS in food safety and quality analysis have not been adequately explored. This review presents the IMS-related analysis and focuses on the application of IMS in food safety and quality. This review presents the important topics including detection of traces of chemicals, rate of food spoilage and freshness, food adulteration and authenticity as well as natural toxins, pesticides, herbicides, fungicides, veterinary, and growth promoter drug residues. Further, persistent organic pollutants (POPs), acrylamide, polycyclic aromatic hydrocarbon (PAH), biogenic amines, nitrosamine, furfural, phenolic compounds, heavy metals, food packaging materials, melamine, and food additives were also examined for the first time. Therefore, it is logical to predict that the application of the IMS technique in food safety, food quality, and contaminant analysis will be impressively increased in the future. HighlightsCurrent status of IMS for residues and contaminant detection in food safety.To assess all the detected contaminants in food safety, for the first time.Identified IMS-related parameters and chemical compounds in food safety control.

Release of Melamine and Formaldehyde from Melamine-Formaldehyde Plastic Kitchenware

The release of melamine and formaldehyde from kitchenware made of melamine resins is still a matter of great concern. To investigate the migration and release behavior of the monomers from melamine-based food contact materials into food simulants and food stuffs, cooking spoons were tested under so-called hot plate conditions at 100 °C. Release conditions using the real hot plate conditions with 3% acetic acid were compared with conditions in a conventional migration oven and with a release to deionized water. Furthermore, the kinetics of the release were studied using Arrhenius plots giving an activation energy for the release of melamine of 120 kJ/mol. Finally, a correlation between quality of the resins, specifically the kind of bridges between the monomers, and the release of melamine, was confirmed by CP/MAS ¹³C-NMR measurements of the melamine kitchenware. Obviously, the ratio of methylene bridges and dimethylene ether bridges connecting the melamine monomers during the curing process can be directly correlated with the amount of the monomers released into food.

Melamine migration measurement through spectrophotometry device and the effect of time and tableware type on it

Melamine is an organic-based chemical material widely used in the production of tableware. Given the adverse effects of melamine on human health, melamine tableware can be a source for its introduction into the human body. The aim of this study was to use a simple method for monitoring the rate of melamine migration from the tableware to food and the effect of time and tableware on this migration. To measure the migration, spectrophotometry was used. The limit of detection (LOD) of the method was 0.2 (μg/ml), which is functional for measuring the rate of migration. The investigation of sample migration of melamine tableware revealed that migration has occurred across all samples. The rate of migration in all samples was less than the standard level of the European Union (30 μg/ml). Statistical analysis indicated that time is an important factor in melamine migration, which significantly increased (p<0.05) in 93% of cases with lengthening the contact time from 30 minutes to 90 minutes. The type of tableware (new or old) and production conditions (standard or non-standard) were found to significantly affect (p<0.001) the rate of migration. Statistical analysis of the results suggested that old tableware increased melamine migration in 41% of cases (p<0.05). Non-standard tableware significantly (p<0.001) increased the rate of migration and thus the effect of non-standard production on melamine tableware was more significant than the age of the tableware.

Measurement of melamine migration from melamine-ware products by designed HPLC method and the effect of food-type on the level of migration

Melamine-ware is widely used around the world. There is a public health concern as regards the safety of melamine when exposed to food. This study was carried out to measure the level of melamine migration in melamine-ware products by HPLC method and the effect of food-type on the level of melamine migration. In food control laboratories in Iran, there is no common method to measure and monitor melamine migration, hence a method using HPLC technique was adopted and validated to solve this problem. The validation results showed the reliability with 94.9% accuracy and 95.3% precision. Furthermore, the limit of detection (LOD) and quantification (LOQ) were 0.145 and 0.435 μg/ml, which for a new method were within acceptable ranges. Melamine migrations from 4 most available melamine wares were measured. Distilled water, 3% acetic acid and 15% ethanol were used as food simulant at 30 °C for 90 min. Although melamine migration occurred in all samples and acidic conditions had a significant effect, the values were not higher than the European standard (30 μg/ml). The study revealed that the HPLC method was valid and could be applied and developed to measure melamine migration. However, precautions should be considered while choosing melamine-ware utensil as long-term exposure to this substance has a negative effect on health, especially on the kidneys.

Melamine contamination in milk powder in Uruguay

Forty samples of milk powder purchased in Uruguay were analysed to assess melamine (MEL) levels. Trichloroacetic acid and acetonitrile were used to extract and precipitate milk proteins previously to clean up of the samples by solid-phase extraction and then were determined by liquid chromatography coupled to ultraviolet detection. The limit of detection (LOD) and limit of quantification (LOQ)of MEL were 0.006 and 0.019 mg kg^-1, respectively. Milk was fortified with MEL at three levels, producing average recoveries higher than 83.8%. The values for positive samples ranged from 0.017 to 0.082 mg kg^-1. Nine samples were positive. Three of them had concentrations between LOD and LOQ. The mean MEL contamination was 0.028 mg kg^-1. Consumption of milk powder containing these levels of MEL does not constitute a health risk for consumers.

Melamine, beyond the kidney: A ubiquitous endocrine disruptor and neurotoxicant?

Melamine is commonly used in a variety of consumer products such as furniture, dining ware, and food utensils. The chemical infamously gained worldwide attention by its illegal addition to a variety of foodstuffs in order to falsify protein content, which led to serious, sometimes fatal, health impacts in children and pets. This resulted in a large amount of published primary studies and reviews of the impacts of melamine exposure on kidney function. However, a growing body of literature suggests that melamine may have impacts beyond renal dysfunction. We conducted a scoping review of this literature which yielded more than 40 studies with human, animal, and in vitro findings. Neurological impacts, reproductive function, and anthropometric outcomes were identified as possible candidates for systematic review based on evidence stream and replication of endpoints. The results of this analysis provide a basis for prioritizing future research on health impacts associated with melamine exposure.

Assessing Risk-Based Upper Limits of Melamine Migration from Food Containers

Melamine contamination of food has become a major food safety issue because of incidents of infant disease caused by exposure to this chemical. This study was aimed at establishing a safety limit in Taiwan for the degree of melamine migration from food containers. Health risk assessment was performed for three exposure groups (preschool children, individuals who dine out, and elderly residents of nursing homes). Selected values of tolerable daily intake (TDI) for melamine were used to calculate the reference migration concentration limit (RMCL) or reference specific migration limit (RSML) for melamine food containers. The only existing values of these limits for international standards today are 1.2 mg/L (0.2 mg/dm² ) in China and 30 mg/L (5 mg/dm² ) in the European Union. The factors used in the calculations included the specific surface area of food containers, daily food consumption rate, body weight, TDI, and the percentile of the population protected at a given migration concentration limit (MCL). The results indicate that children are indeed at higher risk of melamine exposure at toxic levels than are other groups and that the 95th percentile of MCL (specific surface area = 5) for children aged 1-6 years should be the RMCL (0.07 mg/dm² ) for protecting the sensitive and general population.

Migration of formaldehyde and melamine from melaware and other amino resin tableware in real life service

The migration of formaldehyde and melamine monomers has been measured on 90 samples of plastic tableware in three different situations - new articles, already used articles and artificially aged articles - by using simulant, contact times and temperatures prescribed by Commission Regulation (EU) No. 10/2011. Formaldehyde was determined by ultraviolet spectroscopy analysis of the coloured complex obtained by reaction with chromotropic acid. Melamine was measured by an ultra high performance liquid chromatography method. Fourier Transformed - Infrared Analysis was applied to characterise the plastic. The results highlighted the presence of different amino resins based on formaldehyde-melamine, urea-formaldehyde or melamine-urea-formaldehyde with different migration behaviour. The migration of monomers was related to progressive degradation of the resins. Ageing studies demonstrated that the potential degradation of the resins and the consequent migration of the monomers may continue throughout the service life of the product. The specific migration limit (SML) of melamine was exceeded after ageing.

A Simple HPLC-DAD Method for the Analysis of Melamine in Protein Supplements: Validation Using the Accuracy Profiles

The study presents a fully validated simple high-performance liquid chromatography method with diode array detection (HPLC-DAD), able to accurately determine the melamine, fraudulently added, in protein supplements, commonly used from healthy adults to enhance exercise or sport performance. The validation strategy was intentionally oriented towards routine use and the reliability of the method rather than extreme performance. For this reason, validation by accuracy profile, including estimation of uncertainty, was chosen. This procedure, based on the concept of total error (bias + standard deviation), clearly showed that this method was able to determine melamine over the range of 0.05–3.0 mg Kg−1, selected by taking into account the maximum residue levels (MRLs) proposed by European legislation to distinguish between the unavoidable background presence of melamine and unacceptable adulteration. The accuracy profile procedure established that at least 95% of the future results obtained with the proposed method would be within the ±15% acceptance limits of the validated HPLC-DAD method over the whole defined concentration range.