Development, validation and accreditation of a method for the determination of Pb, Cd, Cu and As in seafood and fish feed samples

Determination of heavy metals from Aloe vera by- product in golden mullet (Liza aurata); A consumer health risk assessment

Heavy metals have become subject of concern in the recent years because of its potency to cause cardiovascular diseases and other toxic health effects. Therefore, this research was assumed to investigate the level of toxicity in terms of heavy metals accumulation in the fish samples and its benefits and risk for human consumers health and also evaluate the partial replacement of plant sources by canarian Aloe vera diets as a pure product or like a by-product on toxicological effects on the golden mullet (Liza aurata) fillet and whole body. In this study risks arising from fish metal content has been measured using various parameters as Estimated Daily Intake (EDI), Maximum Safe Consumption (MSC_A), Target Hazard quotient (THQ), Hazard Index (HI) Carcinogenic risk of As (As- CR), the Value Selenium Health Benefit (Se HBV) and also the Nutritional Values has been evaluated. The results showed that all heavy metal levels in the fish tissue and diets were below the confirmed safe limits for consumption. In case of diets, it is obvious that with the exception of As, Hg, and Se, the presence of heavy or essential metals in both whole fish and raw fillet in golden grey mullet given experimental diets revealed that the whole fish had the highest concentration. Thus, it can be concluded that Aloe vera product and byproduct were in safety limits for fish and also for humans through food chain. Various risk and benefit assessment measures established by national and international authorities concluded that Liza aurata use was mostly safe.

An ultra-sensitive electrochemical aptasensor for simultaneous quantitative detection of Pb2+ and Cd2+ in fruit and vegetable

An electrochemical aptasensor based on aptamer was designed for the first time to simultaneously detect Cd²⁺ and Pb²⁺ in fruit and vegetable. The double-stranded DNA including aptamers were immobilized on the electrode via Au-S bond. Due to the specific binding of aptamer and metal ions, the aptamers labelled with methylene blue or ferrocene were competed off the gold electrode, and the electrochemical signal was decreased. Under the optimal conditions, the electrochemical aptasensor showed linear response to Cd²⁺ and Pb²⁺ in the range of 0.1 to 1000 nmol/L, and the detection limits of Cd²⁺ and Pb²⁺ achieved 89.31 and 16.44 pmol/L (3σ), respectively. Excellent stability and reproducibility were exhibited with RSD 2.27% (Cd²⁺) and 3.61% (Pb²⁺). The digested fruit and vegetable were also tested, and the recoveries were in the range of 90.06% to 97.24%. Thus, this strategy held great potential in monitoring cadmium and lead pollution.

Heavy metal concentrations in wild and farmed gilthead sea bream from southern Mediterranean Sea-human health risk assessment

Arsenic, cadmium, copper, lead, and zinc concentrations in the edible part of wild and farmed Sparus aurata from Algerian coastal were determined. The highest concentrations of cadmium (0.0078 mg kg^-1 wet weight), copper (0.98 mg kg^-1 w.w), and zinc (5.1 mg kg^-1 w.w) were recorded in farmed sea bream, whereas the highest arsenic (5.02 mg kg^-1 w.w) and lead (0.006 mg kg^-1 w.w) levels were registered in wild one. The statistical analysis (Friedman test, p < 0.05) indicated that the origin of fish (wild, farmed in a cage, and farmed in raceway) has relevance to the distribution of metal. Estimated weekly intake of inorganic arsenic, cadmium, and lead for a 72.5-kg person consuming Sparus aurata from Algeria does not exceed 1% of the WHO/JECFA recommended rate for all metals, certainly due to the limited consumption of seafood products by the local population. The total target hazard index is far less than "one" 1, and the carcinogenic risk for arsenic exceeds the acceptable value of 10^-5. Based on the result of this study, the potential risk to human health from the consumption of contaminate farmed sea bream (in the cage) should be considered.

Elemental analysis of fish feed by laser-induced breakdown spectroscopy

In this study, the potential of laser-induced breakdown spectroscopy (LIBS) as an efficient multi-elemental quantification tool for fish feed is determined. A particular focus of this paper is total chromium, an essential element that has the potential to be toxic and carcinogenic. In total six elements, four macro-elements (Ca, Fe, K and Mg) and two micro-elements (Cr and Rb), were modelled using LIBS spectra of aquafeed samples. Reference analysis was conducted via inductively coupled plasma mass spectrometry (ICP-MS) and showed good agreement with LIBS predictions. These results provide evidence that LIBS has the potential to be utilized in the field as a real-time screening tool for establishing the elemental composition of a range of fish feeds.

Inexpensive and green electrochemical sensor for the determination of Cd(II) and Pb(II) by square wave anodic stripping voltammetry in bivalve mollusks

An inexpensive and environmental friendly electrochemical sensor based on a glassy carbon electrode (GC) modified with graphene quantum dots (GQDs) and Nafion (NF) has been developed for the determination of Cd(II) and Pb(II) in bivalve mollusks using square wave anodic stripping voltammetry (SWASV). GQDs were characterized by UV-Vis spectroscopy, fluorescence and transmission electronic microscopy (TEM). The modified electrode was evaluated by cyclic voltammetry, scanning electronic microscopy (SEM) and electrochemical impedance spectroscopy (EIS). A linearity of 20-200 μg L^-1 was found, with a limit of detection (LOD) of 11.30 μg L^-1 for Cd(II) and 8.49 μg L^-1 for Pb(II). The proposed methodology was validated with a certified reference material TMDA-64.2. The reproducibility of GC/GQDs-NF for both species had an RSD of less than 10%. The results were compared with ICP-OES. The method was applied in the determination of Cd(II) and Pb(II) in bivalve mollusks samples with excellent results.

Trace elements concentrations in squids consumed in Shandong Province China and their associated risks to the human health

Determination of ten metal levels in 160 squid samples caught from offshore and the oceanic fishing locations by ICP-MS was made. The mean metal concentration in the squid muscles decreasing in the order of: Zn, Fe, Cu, As, Mn, Se, Cd, Pb, Cr and Ni. Metal concentrations in the squids were assessed for human uses according to provisional tolerable weekly intake (PTWI) and provisional tolerable daily intake (PTDI)·The estimated hazard quotients for the individual metals from squids were found in accordance to the following sequence: As > Cd > Cu > Se > Cr > Zn > Pb > Fe > Mn > Ni, with the greatest hazard upon human health coming primarily from As (1.34 < HQ < 1.73 in the Loliginidae from two offshore sampling sites and the Humboldt squid from the eastern Pacific Ocean). In regards to the heavy metal pollution of the coastal sea areas, the squids captured from offshore sites might pose a higher potential health risk to consumers compared to those from the ocean.

Development of a Rapid Method for the Determination of Caffeine in Coffee Grains by GC-FID-A Fully Validated Approach

A simple method for the determination of caffeine in coffee grains by GC-FID (Gas Chromatography-Flame Ionisation Detector) is presented in the current work. The method was fully validated according to ISO (International Organization for Standardization) 17025 requirements and European Commission regulations. The accuracy, as provided by recovery experiments, was higher than 93%, and the precision, as provided by the (%) relative standard deviation under reproducibility conditions, was lower than 5%. A vast number of independent parameters that lead in the increase of uncertainty of methods were investigated. The analysis was performed without use of an internal standard, which was proven to be reliable according to several validation methods. The method was applied in real samples, and possible health claims were investigated.

HMF and diastase activity in honeys: A fully validated approach and a chemometric analysis for identification of honey freshness and adulteration

A fully validated approach for the determination of diastase activity and hydroxymethylfurfural content in honeys were presented in accordance with the official methods. Methods were performed in real honey sample analysis and due to the vast number of collected data sets reliable conclusions about the correlation between the composition and the quality criteria were exported. The limits of detection and quantification were calculated. Accuracy, precision and uncertainty were estimated for the first time in the kinetic and spectrometric techniques using the certified reference material and the determined values were in good accordance with the certified values. PCA and cluster analysis were performed in order to examine the correlation among the artificial feeding of honeybees with carbohydrate supplements and the chemical composition and properties of the honey. Diastase activity, sucrose content and hydroxymethylfurfural content were easily differentiated and these parameters were used for indication of the adulteration of the honey.

Mercury accumulation in marine fish most favoured by Malaysian women, the predictors and the potential health risk

We identified marine fish species most preferred by women at reproductive age in Selangor, Malaysia, mercury concentrations in the fish muscles, factors predicting mercury accumulation and the potential health risk. Nineteen most preferred marine fish species were purchased (n = 175) from selected fisherman's and wholesale market. Length, weight, habitat, feeding habit and trophic level were recognised. Edible muscles were filleted, dried at 80 °C, ground on an agate mortar and digested in Multiwave 3000 using HNO₃ and H₂O₂. Total mercury was quantified using VP90 cold vapour system with N₂ carrier gas. Certified reference material DORM-4 was used to validate the results. Fish species were classified as demersal (7) and pelagic (12) or predators (11), zoo benthos (6) and planktivorous (2). Length, weight and trophic level ranged from 10.5 to 75.0 cm, 0.01 to 2.50 kg and 2.5 to 4.5, respectively. Geometric mean of total mercury ranged from 0.21 to 0.50 mg/kg; maximum in golden snapper (0.90 mg/kg). Only 9 % of the samples exceeded the JECFA recommendation. Multiple linear regression found demersal, high trophic (≥4.0) and heavier fishes to accumulate more mercury in muscles (R ² = 27.3 %), controlling for all other factors. About 47 % of the fish samples contributed to mercury intake above the provisional tolerable level (45 μg/day). While only a small portion exceeded the JECFA fish Hg guideline, the concentration reported may be alarming for heavy consumers. Attention should be given in risk management to avoid demersal and high trophic fish, predominantly heavier ones.