A comparative analytical assessment of iodides in healthy and pathological human thyroids based on IC-PAD method preceded by microwave digestion

Pretreatment methods in ion chromatography: A review

As an advanced analytical technology, Ion Chromatography (IC) has been widely used in various fields. At present, it is faced with the challenges of sample complexity and instrument precision. It is necessary to select appropriate pretreatment methods to achieve sample preparation and protect the instruments. Therefore, this paper reviews several commonly used sample pretreatment technologies in IC, focusing on sample digestion and purification techniques. Additionally, we introduce some advanced IC technologies and automatic sample processing devices. We provide a comprehensive summary of the basic principles, primary applications and the advantages and disadvantages of each method. Pretreatment methods should be carefully selected and optimized on the specific characteristics of the sample and the ions to be measured, in order to achieve better analysis results.

Determination of inorganic anions in the whole blood by ion chromatography

A fast, precise, and accurate method that can simultaneously determine 7 anions in whole blood was established by on line dialysis-double suppression ion chromatography. Performance parameters which could affect the determination of anions were optimized, including the selection of protein precipitant in samples, the amount of filtrate discarded, selection of eluent flow rate, influence of the Ag-Na column on experimental results, influence of ethylenediamines on ClO₂^-, and investigation of nitrogen drying. Finally, 3.6 mmol/L sodium carbonate was selected as eluent, with a flow rate of 0.8 mL/min, to separate the 7 anions. Blood and alcohol (v/v, 1:4) were used to precipitate the proteins in blood. The 7 anions reached an adequate recovery rate when the first 2 mL of filtrate from the C18 column was discarded. The recovery rate at LLOQ, low, medium, and high concentrations was 80-120%. The correlation coefficients (r²) of the calibration curves of the targeted anions ranged from 0.9975 to 0.9998. The limit of detection (LOD) was 0.309-7.71 μg/L. This method has simple pretreatment, high accuracy, and good reproducibility and selectivity, and is suitable for the separation and determination of anions in blood.

Hair Trace Elements are Associated with Increased Thyroid Volume in Schoolchildren with Goiter

The objective of the study was analysis of hair trace elements content in children with goiter living in Aktubinsk region. Children with goiter and age- and sex-adjusted controls were involved in the current study. Hair trace elements content was assessed using inductively coupled plasma mass spectrometry. Thyroid volume was measured using an ultrasound scanner and compared to the previously calculated normal values. The obtained data indicate that children with goiter were characterized by 20 and 15 % lower values of hair Cr and Zn, and 66, 42, 16, and 42 % higher hair levels of I, Mn, Si, and V as compared to the control values, respectively. Moreover, children with goiter were characterized by a twofold higher hair B levels than the control ones. Correlation analysis demonstrated a significant direct association only between thyroid volume and hair B (r = 0.482; p = 0.004), I (r = 0.393; p = 0.021), Mn (r = 0.364; p = 0.034), and Si (r = 0.446; p = 0.008) levels. It is also notable that hair I content was interrelated only with Si (r = 0.346; p = 0.045). No significant correlation was detected between I and B (r = 0.250; p = 0.155) and Mn (r = 0.076; p = 0.669) in hair of children. It is hypothesized that an increase in thyroid volume in children is associated with a complex interplay of iodine with other trace elements rather than with altered iodine status itself.

Rapid measurement of free cyanide in liquor by ion chromatography with pulsed amperometric detection

This study investigated the measurement of free cyanide in liquor by ion chromatography coupled with pulsed amperometric detection (IC-PAD). Eluent concentration, interferent evaluation and method performance were discussed. Results show that free cyanide in liquor can be rapidly determined by the optimised IC-PAD method. A sample requires only 1:100 dilution and simple filtration before being subjected to IC-PAD. The linear range is 1-5000 μg/L with an R value of 0.9998. The detection limit is 1 μg/L for a 25 μL injection loop. The overall relative standard deviation (RSD) of the method is less than 5%, and the recovery range is from 98.1% to 105.0%. This study has been proven significant and may have potential applications in liquors analysis.

Determination of total iodine in serum and urine samples by ion chromatography with pulsed amperometric detection - studies on analyte loss, optimization of sample preparation procedures, and validation of analytical method

A fast, accurate and precise ion chromatography method with pulsed amperometric detection was applied to evaluate a variety of parameters affecting the determination of total iodine in serum and urine of 81 subjects, including 56 obese and 25 healthy Polish children. The sample pretreatment methods were carried out in a closed system and with the assistance of microwaves. Both alkaline and acidic digestion procedures were developed and optimized to find the simplest combination of reagents and the appropriate parameters for digestion that would allow for the fastest, least time consuming and most cost-effective way of analysis. A good correlation between the certified and the measured concentrations was achieved. The best recoveries (96.8% for urine and 98.8% for serum samples) were achieved using 1ml of 25% tetramethylammonium hydroxide solution within 6min for 0.1ml of serum/urine samples. Using 0.5ml of 65% nitric acid solution the best recovery (95.3%) was obtained when 7min of effective digestion time was used. Freeze-thaw stability and long-term stability were checked. After 24 weeks 14.7% loss of iodine in urine, and 10.9% in serum samples occurred. For urine samples, better correlation (R(2)=0.9891) of various sample preparation procedures (alkaline digestion and application of OnGuard RP cartidges) was obtained. Significantly lower iodide content was found in samples taken from obese children. Serum iodine content in obese children was markedly variable in comparison with the healthy group, whereas the difference was less evident when urine samples were analyzed. The mean content in serum was 59.12±8.86μg/L, and in urine 98.26±25.93 for obese children when samples were prepared by the use of optimized alkaline digestion reinforced by microwaves. In healthy children the mean content in serum was 82.58±6.01μg/L, and in urine 145.76±31.44μg/L.