A practical method for the determination of sulphur in coal samples by high-resolution continuum source flame atomic absorption spectrometry

Fast sequential multi element analysis of lead and cadmium in canned food samples using effervescent tablet-assisted switchable solvent based liquid phase microextraction (EA-SS-LPME) coupled with high-resolution continuum source flame atomic absorption spectrometry (HR-CS-FAAS)

An effervescent tablet-assisted switchable solvent based liquid phase microextraction (EA-SS-LPME) was developed for multi-element determination of Pb and Cd in various samples using high-resolution continuum source flame atomic absorption spectrometry (HR-CS-FAAS). The effervescent tablets were used for improving the extraction efficiency. Triethylamine as a hydrophobic solvent was switched to protonated triethylamine carbonate by CO₂ and used to extract dithizone complexes from samples. Calibration linearities were obtained from 0.06 to 10.0 mg L^-1 (Pb) and 0.02 to 1.50 mg L^-1 (Cd). LODs of the proposed method were 0.0195 (Pb) and 0.0068 (Cd). LOQs were 0.0649 mg L^-1 (Pb) and 0.0228 mg L^-1 (Cd) with %RSDs of 1.25%-1.69% (Pb) and 1.07%-1.64% (Cd). The proposed method was applied for the determination of Pb and Cd in water and canned food samples. The spiked recoveries were 82.3-119.0% (Pb) and 81.7-120.0% (Cd). In addition, the PF was 3.3, with EF at 1.4 (Pb) and 2.6 (Cd) obtained after extraction for under 8 min.

Development of a novel and green microwave-assisted hydrogen peroxide digestion method for total sulphur quantitative extraction in coal samples prior to inductively coupled plasma-optical emission spectroscopy and ion-chromatography determination

Novel, rapid and green microwave-assisted digestion using diluted hydrogen peroxide followed by ICP-OES and IC analysis for total sulphur determination in coal samples.

Direct and Sequential Determination of Six Metal Elements in Cooking Wine by HR-CS GFAAS

The aim of this work was to develop a sensitive, simple and direct procedure for the determination of Cu, Cd, Cr, Pb, Mn and Al in the cooking wine by HR-CS GFAAS with a minimum sample pre-treatment. The analyses of the six metal elements were conducted using a high resolution continuum source atomic absorption spectrometer. The cooking wine as sample was just diluted in ultrapure water with 1.0% (v/v) HNO3and the analytical lines of the six metal elements were selected scientifically. The correlation coefficients better than 0.99 were obtained and the limits of detection were 0.86, 0.08, 0.28, 0.81, 0.61 and 1.54 μg/L for Cu, Cd, Cr, Pb, Mn and Al, respectively. Recoveries varied form 96.1% to 105.7%. The proposed method was applied to the determination of the six metal elements in the cooking wine and the results showed that the mass concentrations of Cu, Cd, Cr, Pb, Mn and Al were 2.10, 0.177, 7.98, 1.86, 22.3 and 217.2 μg/L, respectively. There was a good agreement between the proposed method and the microwave digestion-HR-CS GFAAS method, and F-test and t-test at 95% of confidence had no significant difference. Therefore, the proposed method was accurate and stable with a high practical value. It provided scientific basis for quality control in food industries.

A new approach for the determination of sulphur in food samples by high-resolution continuum source flame atomic absorption spectrometer

The new approach for the determination of sulphur in foods was developed, and the sulphur concentrations of various fresh and dried food samples determined using a high-resolution continuum source flame atomic absorption spectrometer with an air/acetylene flame. The proposed method was optimised and the validated using standard reference materials, and certified values were found to be within the 95% confidence interval. The sulphur content of foods ranged from less than the LOD to 1.5mgg(-1). The method is accurate, fast, simple and sensitive.

Sequence Determination of Cd and Pb in Honey by Incomplete Digestion-High Resolution Continuum Source Graphite Furnace Atomic Absorption Spectrometry

A fast and effective method was developed for sequence determination of Cd and Pb in honey by incomplete digestion-high resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS). Cd and Pb in some honey samples using incomplete digestion treatment were measured by HR-CS GFAAS. The factors influencing determination were investigated by single factor experimental design. The optimal determination conditions were found as follows: NH4H2PO4(10mg/mL) were added as a chemical modifier with the volume of 5μL; pyrolysis temperature 600°C(Cd) and 800°C(Pb); atomization temperature 1100°C(Cd) and 1400°C(Pb). Detection limits (3σ,n=12) were found to be 0.06 μg/L and 0.78 μg/L for Cd and Pb, respectively. The precisions (RSD) for 6 replicate measurements of Cd and Pb in honeys were 3.8% and 2.6%, respectively. Recoveries of added Cd and Pb were varied from 95% to 103%. Therefore, the proposed method was rapid, accurate and stable with a high practical value. It provided scientific basis for multi-element sequence determination in food.

Determination of total sulfur in food samples by solid sampling high-resolution continuum source graphite furnace molecular absorption spectrometry

The determination of sulfur in food samples via the rotational molecular absorption of carbon monosulfide (CS) was performed using a solid sampling high-resolution continuum source electrothermal atomic absorption spectrophotometer (SS-HR-CS-ETAAS). In the presence of plenty of carbon in the graphite furnace as well as in food samples, CS was formed in the gas phase without the addition of any molecule forming element externally. The effects of the wavelength selected to detect CS, graphite furnace program, amount of sample, coating of the graphite tube and platform with Ir, and the use of a Pd modifier on the accuracy, precision, and sensitivity were investigated and optimized. Sulfur was determined in an iridium-coated graphite tube/platform at 258.056 nm by applying a pyrolysis temperature of 1000 °C and a molecule forming temperature of 2400 °C. The calibration curve prepared from Na2S was linear between 0.01 μg (LOQ) and 10 μg of S. The accuracy of the method was tested by analyzing certified reference spinach and milk powder samples by applying a linear calibration technique prepared from aqueous standard. The results were in good agreement with certified values. The limit of detection and characteristic mass of the method were 3.5 and 8.1 ng of S, respectively. By applying the optimized parameters, the concentrations of S in onion and garlic samples were determined.