Simultaneous Determination of Nitrate and Nitrite in Fish Products with Improved Sensitivity by Sample Stacking-Capillary Electrophoresis

Abstract

A fast and reproducible method for the simultaneous determination of nitrate and nitrite ions in canned fish samples by capillary zone electrophoresis has been developed. The sensitivity of the method was increased by applying a sample stacking technique. Optimal separation conditions were selected as 30 mmol L −1 formic acid and 30 mmol L −1 sodium sulfate at a pH of 4.0. The separation of nitrate and nitrite ions was achieved within 2.5 min. The limits of detection obtained at a signal-to-noise ratio of 3 for nitrate and nitrite were 0.55 and 0.82 μmol L −1 , while the relative standard deviations of intra-day corrected peak areas were 0.99 and 2.74 %, respectively. Recovery values ranged between 88.7 and 104 % for both ions. The method was successfully applied to canned fish samples, namely tuna, mackerel and sardine.

Recent progress of sample stacking in capillary electrophoresis (2016–2018)

“…Kalaycionglu et al. presented a fast and reproducible CE‐LVSS method for the simultaneous determination of nitrate and nitrite ions in canned fish samples. With a BGE containing 30 mM formic acid and 30 mM sodium sulfate at pH 4.0 and UV detection at 210 nm, the LODs obtained were 0.55 and 0.82 μM, respectively.…”

Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2016–2018)

“…In LVSEP, the EOF that is smaller and opposite to the electrophoretic mobility of the analytes is used to pump the sample matrix out of the capillary. LVSEP has been used for sensitive and efficient determination of nitrate and nitrite in canned fish samples ; d ‐ and l ‐ isomers of aspartate and glutamate with enrichment factor of 480 ; anti‐microbial agent, pentamidine in rat plasma ; ammonia, amines (including cyclohexylamine, ethanolamine, morpholine, hydrazine, dimethylamine, and triethanolamine) and their degradation products, e.g., methylamine, ethylamine, and diethanolamine in steam water ; and DNA fragments . Multistep pressure assisted LVSEP, in which injection of large sample volumes and pressure assisted electroosmotic pumping of the sample matrix out of the capillary was performed in repeated cycles to improve the sensitivity (enhancement factors up to 170) of amyloid β (Aβ) peptides, biomarkers for Alzheimer's disease diagnosis, in cerebrospinal fluid .…”

A sample stacking-capillary electrophoresis method for simultaneous determination of nitrate and thiocyanate ions of ultra-heat-treated milk samples

“…A recently published CE procedure for the simultaneous determination of nitrite and nitrate ions in processed fish products was adapted for the separation of nitrate and thiocyanate ions in milk samples. 23 Electroosmotic flow inside the capillary was reduced using a separation electrolyte at a low pH. Samples were injected from the negative electrode side and the polarity was changed.…”