Use of Multivariate Optimization to Develop Methods for Direct Copper and Lead Determination in Breast Milk by Graphite Furnace Atomic Absorption Spectrometry

A direct method for lead and copper determination in breast milk by graphite furnace atomic absorption spectrometry, using aqueous calibration, was proposed in this study. Samples were diluted with hydroximethylaminomethane 80 %?v/v, pH 8. The dilution determination for Pb and Cu was 1:1 and 1:9, respectively. Fractional factorial (2^4?1) and central composite designs were used to optimize experimental conditions (pyrolysis and atomization temperatures, pyrolysis time, and modifier) using 10 μL samples introduced into a graphite furnace. The methods allowed for copper and lead determination under optimized conditions with an aqueous calibration curve between 0 and 180 μg L^?1 for Cu and 0 and 48 μg L^?1 for Pb. The detection limits were 0.92 μg L^?1 and 6.4 μg L^?1 for Pb and Cu, respectively. Intra and inter-assay studies revealed coefficients of variation of 5.0 and 6.3 %, and 6.4 and 5.5 % for Pb and Cu, respectively. Recovery studies at three concentration levels (three consecutive days, n?=?7/day) presented results between 107 and 109 % for Pb and 102 and 103 % for Cu. Good accuracy was obtained for both metals through recoveries studies using certified reference material (infant formula NIST® 1846). The method determined lead and copper in six samples and the concentrations ranged from 2.90 to 27.9 μg L^?1 for Pb and 384 to 1,212 μg L^?1 for Cu. While copper is an essential element, lead has no nutritional function and is cumulative at low concentrations. Therefore, safe, efficient, and validated methods should be available to determine its concentration in breast milk.     

Dual-Label Chemiluminescence Strategy for Multiplexed Immunoassay of 20 Fluoroquinolones, 15 β-Lactams, 15 Sulfonamides,and CAP in Milk

In this paper, a novel dual-label time-resolved chemiluminescent multiplexed immunoassay (DLTRC-MIA) based on the distinction of the kinetic characteristics of horseradish peroxidase (HRP) and alkaline phosphatase (ALP) with approximate estimation approach for simultaneous determination of 20 fluoroquinolones (FQs), 15 β-lactams, 15 sulfonamides (SAs), and chloramphenicol (CAP) in milk was developed. The strategy integrated a single-chain variable fragment–alkaline phosphatase fusion protein (scFv-ALP), a recombinant penicillin-binding protein (PBP) 2×*, a monoclonal antibody (MAb), and a polyclonal antibody (PAb) in one immunoassay and in a single well together to fulfill the simultaneous detection of 51 low-molecular weight contaminants (20 FQs, 15 β-lactams, 15 SAs, and CAP). The limits of detection for FQs, β-lactams, SAs, and CAP range from 0.29 μg L^?1 for ciprofloxacin (CIP) to 81.6 μg L^?1 for trovafloxacin (TRO), 0.27 μg L^?1 for ceftiofur (CEF) to 44.1 μg L^?1 for cephalexin (CEL), 0.089 μg L^?1 for sulfadimethoxine (SDM) to 2.7 μg L^?1 for sulfadiazine (SDZ), and 0.028 μg L^?1 for CAP, respectively. The results demonstrated that the detection limits of DLTRC-MIA meet the requirement of detection levels for 51 drug residues in milk, suitable for high-throughput screening of low-molecular weight contaminants.     

Simple and fast spectrophotometric determination of low levels of thiabendazole residues in fruit and vegetables after pre-concentration with ionic liquid phase microextraction

There is a great importance of monitoring thiabendazole (TBZ) residues in fruits and vegetables to ensure food safety. Therefore, a new ionic liquid (IL) phase microextraction method using IL, 1-butyl-3-methylimidazoliumhexafluorophosphate [C₄mim][PF₆], as extracting solvent is proposed for simple and fast determination of low levels of TBZ in fruits and vegetables by spectrophotometry. The method is based on selective complex formation of TBZ with Cu(II) ions in presence of PF₆^– as counter ion at pH 5.5, and then microextraction of the complex into the fine micro-drops of IL phase. After optimisation of variables affecting microextraction efficiency, the analytical parameters of the method were determined by calibration curves. The method exhibits a linear relationship (0.3–280 μg L^?1), low detection limit (0.1 μg L^?1), good intra- and inter-day precision (2.4–4.5% as RSD_r%, 2.1–5.6% as RSD_R%), good recovery (≥95.1–98.2%) and high sensitivity enhancement factor (150) by solvent-based calibration curve. It allows a detection limit of 0.24 μg L^?1 and a range of 0.8–250 μg L^?1 by the matrix-matched calibration curve. After validation, the method was successfully applied to the determination of TBZ residues with method quantification limits in fruit and vegetables of 2.0 and 2.5 µg kg^?1 with and without adding polyvinylpyrrolidone (PVP-15) solution. Recoveries range from 85.5% to 98.2% after spiking (10, 50 and 100 µg kg^?1, n: 3).     

Comparison of different digestion methods of green and black tea at the Sarajevo market for the determination of the heavy metal content

The content of Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn was determined in commercially available black and green tea from Sarajevo market. The concentrations of metals in tea infusion and solutions prepared by applying four digestion methods were determined by using FAAS. The results show that the highest concentration of total metals was obtained after acid digestion in an autoclave. The concentration of metals soluble in water obtained in tea infusion does not exceed maximum allowed values provided by WHO (Guidelines for drinking-water quality, World Health Organization, Geneva, 2011). Among the investigated metals Mn was the highest and ranged from 286 to 334 μg g^?1 in tea infusion of green and black tea, respectively, to 1,078 and 1,528 μg g^?1 total content of Mn in green and black tea, respectively. The concentration of heavy metals in water extracts of tea was distinctly low in comparison with the total content. The concentrations of Cd and Pb were under the determination limit using FAAS. The total content of all determined metals was higher in black tea than in green tea.     

Simultaneous Determination of Multiclass Pesticides and Antibiotics in Honey Samples Based on Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

A simple, fast, and efficient method was developed for simultaneous determination of 79 pesticides and 13 antibiotics compounds of different chemical classes of pesticides and antibiotics in honey samples by ultra-high performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS). The sample preparation procedure includes homogenization with McIlvaine buffer 0.1 mol L^?1 (pH 4), followed by extraction with acetonitrile and cleanup with florisil, using dispersive solid phase extraction (d-SPE). The proposed method was validated with good results, such as linearity (r ²?>?0.9901), normality, and independence of the evaluated data, as well as recoveries between 70 and 120 % with relative standard deviation (RSD) <20 % for most of the compounds spiked from 0.1 to 200 μg kg^?1. The experimental method limits of detection and quantification were from 0.03 to 1.51 μg kg^?1 and from 0.1 to 5 μg kg^?1, respectively, for the pesticides. For the antibiotics, the decision limits (0.1 to 2 μg g^?1) and the detection capacity (0.12 to 2.81 μg g^?1) were below the maximum residue limits (MRLs) established for honey by the Brazilian and European legislation. The method was successfully applied to real samples from different botanical and geographic origins. From them, 44 % presented residues from 0.12 to 10 μg kg^?1 of one or more analytes. The proposed method combines the advantages of a quick sample preparation step with the selectivity and sensitivity of the UHPLC-MS/MS and proved to be suitable for routine analyses.     

Migration of lead and arsenic from food contact paper into a food simulant and assessment of their consumer exposure safety

ABSTRACT

Paper is one of the most commonly used food packaging materials. During the production of packaging paper, it is possible for trace amounts of heavy metals to be incorporated as contaminants. These could migrate into food when packaging paper (food contact paper) is used for cooking, storing and eating. The aim of this study was to determine the migration of lead (Pb) and arsenic (As) from food contact paper into a food simulant and then to assess human safety through the estimated daily intake (EDI) with consumption factor. Migration tests were conducted for 310 samples using 4% acetic acid as a food simulant at 25°C for 10 min and at 95°C for 30 min. Concentrations of Pb and As in a food simulant were quantified by inductively coupled plasma mass spectrometry. LODs for Pb and As were 0.002 and 0.005 µg L^?1, respectively. The migration of Pb from food contact paper ranged from not detected (ND) to 17.5 μg L^?1 at 25°C for 10 min and from 0.10 to 25.6 μg L^?1 at 95°C for 30 min while As ranged from ND to 0.44 μg L^?1 at 25°C for 10 min and from ND to 0.87 μg L^?1 at 95°C for 30 min. The migration of Pb and As determined in this study confirm that the human exposure was within safe levels based on the EDI of food contact paper compared with the provisional tolerable weekly intake for Pb of 25 μg kg^?1 bw and for As of 15 μg kg^?1 bw.     

Toxic and micronutrient elements in organic,brown and polished rice in Brazil

Concentration levels of As, Cd, Hg, Pb, Tl, Sn, Sb Co, Cu, Mn, Se, Zn, Cr, Ni and Mo in different types of rice cultivated in irrigated fields in Brazil were evaluated. Arsenic, Cd, Pb, Zn, Mn and Cu were found in higher concentrations in brown rice samples, suggesting the prevalence of these elements in the bran. Meanwhile, lower concentrations of Pb, Mo, Cr, Se and Co were found in parboiled rice. Organic rice did not differ of cultivated conventionally rice. Thallium, Hg and Sb were not detected in any rice sample whose limits of detection were 0.7 μg kg^?1, 2.5 μg kg^?1 and 8 μg kg^?1, respectively. The concentrations of the investigated elements were compared with those reported for polished rice and brown rice from other countries, unveiling concentrations in general at the same level for rice produced at non-contaminated sites.     

A Rapid Quantification of β-Carotene in Fruits and Vegetables by Dispersive Liquid–Liquid Microextraction Coupled with UV–Vis Spectrophotometry: Optimized by Response Surface Methodology

A simple, fast, and efficient method consisted of optimized dispersive liquid–liquid microextraction (DLLME) followed by UV–vis spectrophotometry was developed for determination of β-carotene in fruits and vegetables. Chloroform and methanol were chosen as extraction and disperser solvents, respectively. The extraction process was optimized using a central composite design (CCD) with the optimum points of 115 μL for volume of extraction solvent and 6.5 % (w/v) for salt concentration. Under the optimal conditions, the relative standard deviation (RSD, C?=?500 μg L^?1, n?=?5), limit of detection (LOD), linear dynamic range (LDR), and coefficient of determination (R²) were 1.08 %, 2 μg L^?1, 50–1,500 μg L^?1, and 0.991, respectively. The present method consisted of a simple and fast sample preparation procedure without any antioxidant addition, saponification, and purification was used.     

Antimony Assessment in PET Bottles for Soft Drink

The aim of this work was to develop a method for the determination of antimony (Sb) in polyethylene terephthalate (PET) bottles and to evaluate its migration into soft drink and simulant. In this context, a new procedure for PET sample preparation, using a high pressure asher (HPA), is presented for the determination of Sb by inductively coupled plasma optical emission spectrometry (ICP-OES). The concentration of Sb in PET bottles ranged between 272 and 650 mg kg^?1. The migration of Sb into soft drink after 180 days at 35 °C was below the LOQ, 20 μg L^?1. The specific migration of Sb from the bottle into simulant 3% of acetic acid after the contact per 10 days at 40 °C was less than the LOQ, 23.5 μg L^?1. The results showed that all packaging evaluated contained Sb, but the maximum permissible migration value for Sb, 40 μg L^?1, established by Anvisa and EU, was never exceeded.     

Simultaneous determination of antimony and boron in beverage and dairy products by flame atomic absorption spectrometry after separation and pre-concentration by cloud-point extraction

A new cloud-point extraction (CPE) method was developed for the pre-concentration and simultaneous determination of Sb(III) and B(III) by flame atomic absorption spectrometry (FAAS). The method was based on complexation of Sb(III) and B(III) with azomethine-H in the presence of cetylpyridinium chloride (CPC) as a signal-enhancing agent, and then extraction into the micellar phase of Triton X-114. Under optimised conditions, linear calibration was obtained for Sb(III) and B(III) in the concentration ranges of 0.5–180 and 2.5–600 μg l^?1 with LODs of 0.15 and 0.75 μg l^?1, respectively. Relative standard deviations (RSDs) (25 and 100 μg l^?1 of Sb(III) and B(III), n = 6) were in a range of 2.1–3.8% and 1.9–2.3%, respectively. Recoveries of spiked samples of Sb(III) and B(III) were in the range of 98–103% and 99–102%, respectively. Measured values for Sb and B in three standard reference materials were within the 95% confidence limit of the certified values. Also, the method was used for the speciation of inorganic antimony. Sb(III), Sb(V) and total Sb were measured in the presence of excess boron before and after pre-reduction with an acidic mixture of KI-ascorbic acid. The method was successfully applied to the simultaneous determination of total Sb and B in selected beverage and dairy products.     

Development of an ELISA and Immunochromatographic Assay for Tetracycline,Oxytetracycline, and Chlortetracycline Residues in Milk and Honey Based on the Class-Specific Monoclonal Antibody

A sensitive class-specific monoclonal antibody against tetracyclines (TCs) was generated and used to develop an enzyme-linked immunosorbent assay (ELISA) and an immunochromatographic assay for TC, oxytetracycline (OTC), and chlortetracycline (CTC) detection in milk and honey samples. The dynamic range of detection for TC in ELISA was 0.26–2.00 μg L^?1 with an IC₅₀ of 0.72 μg L^?1. The IC₅₀ value of OTC and CTC was 3.2 and 6.4 μg L^?1, respectively. The recovery of TC, OTC, and CTC in milk samples was 82–102, 91–105, and 90–101 %, respectively, and 88–101, 89–101, and 89–95 % in honey samples, respectively. In the immunochromatographic assay, the cutoff values for TC, OTC, and CTC were 15, 15, and 50 μg L^?1 in milk, respectively, and 40, 40, and 40 μg L^?1 in honey, respectively. The results revealed that ELISA and the immunochromatographic assay can be applied for the rapid and sensitive detection of TC, OTC, and CTC in milk and honey samples.     

Optimized Ultrasound-Assisted Temperature-Controlled Ionic Liquid Microextraction Coupled with FAAS for Determination of Tin in Canned Foods

A simple and rapid method based on ultrasound-assisted temperature-controlled ionic liquid microextraction combined with flame atomic absorption spectrometry (FAAS) has been developed for determination of tin. In this method, Sn(IV)-ammonium pyrrolidinedithiocarbamate (APDC) complex was extracted into a small volume of 1-hexyl-3-methylimidazolium hexafluorophosphate as ionic liquid and after phase separation, the enriched analyte in the final solution is determined by FAAS. Experimental design approaches were used to obtain the best conditions. The variables of interest were temperature, pH, buffer volume, extraction time, centrifugation time and volumes of ionic liquid, methanol, and APDC. The Plackett–Burman design was employed for screening to determine the variables significantly affecting the extraction efficiency. Then, the significant factors were optimized by using a central composite design. In the optimal conditions the calibration graph was linear in the range of 0.10–6.0 mg?L^?1 with a correlation coefficient of 0.997. The limit of detection and relative standard deviation (n?=?5 for determination of 1.0 mg?L^?1) were 42 μg?L^?1 and 1.6 %, respectively. The preconcentration factor was calculated to be 52.7. Finally, the method was successfully applied to the determination of tin in various canned products including peach, pineapple and aloe vera juice, canned pea, and canned cheese.     

Large-Volume Sample Staking of Rice Polyphenols Prior to Their Determination by Non-aqueous Capillary Electrophoresis

A rapid non-aqueous capillary electrophoretic (NACE) method for the separation of (?)-epicatechin (EPI), (+)-catechin (?CAT), kaempferol (KAE), quercetin (QUR), naringanin (NAR), ferulic acid (FA), and p-coumaric acid (p-CA) has been developed and applied to the determination of these compounds in different rice varieties. All seven compounds were separated on capillary of 50 μm?×?68 cm (60-cm effective length) using 20 mmol L^?1 borate buffer of pH 9.0 and 5 % acetonitrile in methanol. Large-volume sample stacking (LVSS) technique was optimized and used to preconcentrate non-detectable polyphenols of white polished rice. Rice extracts were concentrated on-line by LVSS prior to separation by non-aqueous capillary electrophoresis. An improvement of 10–55 times in detectability was achieved with injection at 50 mbar for 30 s followed by voltage inversion (?20 kV) for 5 s. Linear calibration range of 1–300 μg L^?1 and 0.01–60 μg L^?1 was observed for NACE and NACE-LVSS method respectively, with the detection limit of 0.33–2.0 and 0.006–0.19 μg L^?1. Good reproducibility with standard deviations of less than 5 % was achieved. Polyphenol contents of different rice varieties were determined using developed method.     

Electrochemical Determination of Phoxim in Food Samples Employing a Graphene-Modified Glassy Carbon Electrode

Employing a graphene-modified glassy carbon electrode, a sensitive and convenient electrochemical method for the determination of phoxim by linear sweep voltammetry was developed. The electrochemical behavior of phoxim at the modified electrode was studied by cyclic voltammetry. In citric acid–phosphate buffers, the modified electrode exhibited excellent electrocatalytical effect on the reduction of phoxim and this was further used for the determination of phoxim. Under optimized analytical conditions, the reduction peak current showed a linear relationship with the concentration of phoxim in a range of 5.97 to 5,966 μg L^?1, with a correlation coefficient of 0.9993 and a detection limit of 2.39 μg L^?1. The proposed method shows excellent sensitivity, selectivity, and linearity and has been successfully applied for the determination of phoxim in a variety of food samples with satisfactory results.     

Determination of 6-Benzylaminopurine and Hg<Superscript>2+</Superscript> in Bean Sprouts and Drinking Mineral Water by Surface-Enhanced Raman Spectroscopy

A novel method for the determination of 6-benzyladenine (6-BA) in bean sprouts and Hg²⁺ in drinking mineral water by surface-enhanced Raman spectroscopy (SERS) was described. 6-BA exhibits obvious SERS signal by using the substrate of silver nanoparticles (AgNPs), and the presence of Hg²⁺ could cause the decrease of SERS signal of 6-BA. The effects of type of aggregation agent, type and level of pH buffer solution, amount of AgNPs, mixing time, concentration of 6-BA, and reaction time on the SERS signals were investigated. Under the optimized experimental conditions, good linear responses were obtained for 6-BA and Hg²⁺ in the concentration ranges of 10–200 μg L^?1 and 5–200 μg L^?1, respectively. By the present method, the limits of detection (LODs) for the determination of 6-BA and Hg²⁺ are 3.3 and 0.20 μg L^?1, and the recoveries of 6-BA and Hg²⁺ in spiked samples are 85.5–113.0 % and 98.2–111.5 %, respectively.     

Optimization of QuEChERS Procedure Coupled to GC-ECD for Organochlorine Pesticide Determination in Carrot Samples

An optimised version of the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method for simultaneous determination of 14 organochlorine pesticides in carrots was developed using gas chromatography coupled with electron-capture detector (GC-ECD) and confirmation by gas chromatography tandem mass spectrometry (GC-MS/MS). A citrate-buffered version of QuEChERS was applied for the extraction of the organochlorine pesticides, and for the extract clean-up, primary secondary amine, octadecyl-bonded silica (C18), magnesium sulphate (MgSO₄) and graphitized carbon black were used as sorbents. The GC-ECD determination of the target compounds was achieved in less than 20 min. The limits of detection were below the EU maximum residue limits (MRLs) for carrots, 10–50 μg kg^?1, while the limit of quantification did exceed 10 μg kg^?1 for hexachlorobenzene (HCB). The introduction of a sonication step was shown to improve the recoveries. The overall average recoveries in carrots, at the four tested levels (60, 80, 100 and 140 μg kg^?1), ranged from 66 to 111 % with relative standard deviations in the range of 2–15 % (n?=?3) for all analytes, with the exception of HCB. The method has been applied to the analysis of 21 carrot samples from different Portuguese regions, and β-HCH was the pesticide most frequently found, with concentrations oscillating between less than the limit of quantification to 14.6 μg kg^?1. Only one sample had a pesticide residue (β-HCH) above the MRL, 14.6 μg kg^?1. This methodology combines the advantages of both QuEChERS and GC-ECD, producing a very rapid, sensitive and reliable procedure which can be applied in routine analytical laboratories.     

Ultra-Trace Determination of Co (ІІ) in Real Samples Using Ion Pair-Based Dispersive Liquid-Liquid Microextraction Followed by Electrothermal Atomic Absorption Spectrometry

Ion pair-based dispersive liquid-liquid microextraction technique was used for preconcentration and determination of ultra-trace levels of Co (??) followed by electrothermal atomic absorption spectrometry (ETAAS). Thiocyanate (SCN^?) forms an anionic complex with Co (??) followed by addition of cetylpyridinium chloride (CPC) as a positive counterion to produce hydrophobic cobalt-thiocyanate-CPC complex. The resulting hydrophobic complex was extracted into the fine droplets of carbon tetrachloride by dispersive liquid-liquid microextraction (DLLME). In DLLME, a mixture of 1.5 mL of acetone (as disperser solvent) containing 40 μL of carbon tetrachloride (as extraction solvent) was rapidly injected into the sample solution to extract the hydrophobic cobalt-thiocyanate-CPC complex. Under the optimum conditions, the calibration curve was linear in the range of 0.08–1.5 μg L^?1 of Co (??) with a correlation coefficient of 0.9997. The relative standard deviation (RSD, %) based on six replicate analyses of 0.5 μg L^?1 of Co (??) was 3.7 %, and the limit of detection (LOD) was 0.02 μg L^?1. The accuracy of the proposed method was evaluated by the analysis of a certified reference material and spike method. The proposed method was successfully applied for determination of ultra-trace levels of Co (??) in different water samples and spinach leaves.     

Simultaneous Determination of Cyclamate,Acesulfame, and Aspartame in Beverages by Titania-Based RP-HPLC

This paper aims at establishing a rapid method for simultaneous separation and determination of the sweeteners including cyclamate, acesulfame, and aspartame in beverages by titania-based reversed-phase high-performance liquid chromatography. The chromatographic conditions were as follows: a titania Sachtopore-RP C18 column (250?×?4.6 mm; 5 μm) as a separation column, a mixture of water and methanol at a volume ratio of 95:5 containing 1.0 % phosphate acid used as mobile phase, flow rate of 1.0 mL min^?1, and the detection wavelength was 205 nm. The linear ranges of cyclamate and aspartame were 0.02–8.0 mg mL^?1 with limits of detection (LODs) of 16.35 and 19.56 μg mL^?1, respectively, and their limits of quantitation (LOQs) were 55.50 and 68.50 μg mL^?1, respectively. The recoveries of cyclamate were between 93.52 and 103.54 %. The recoveries of aspartame were between 93.31 and 102.63 %. The linear range of acesulfame was 0.125–50 μg mL^?1 with LOD of 0.08 μg mL^?1 and LOQ of 0.25 μg mL^?1. The recoveries of acesulfame were between 94.34 and 103.21 %. Relative standard deviation (n?=?8) for all determinations was less than 0.72 %.     

Determination of Hormones Residues in Milk by Gas Chromatography-Mass Spectrometry

The article presents the use of gas chromatography-mass spectrometry (GC-MS) technique in a method for the determination of 18 anabolic hormones from synthetic stilbenes, steroids and resorcylic acid lactones (RALs) groups in raw milk and milk powder. Sample preparation consisted of liquid-liquid extraction with diethyl ether and purification by solid phase extraction (SPE). Prior to instrumental analysis, the reaction of derivatisation with the heptafluorobutyric anhydride or N-methyl-N-trimethylsilyltrifluoroacetamide was performed. Method validation was carried out according to the required performance criteria of the Commission Decision 2002/657/EC. The apparent recovery of all analytes at 1 μg L^?1 (kg^?1) level was ranged between 70.4 and 119.4 % with the coefficients of variation values less than 30 %. The decision limits (CCα) and the detection capabilities (CCβ) were in the range of from 0.11 to 0.44 μg L^?1 (kg^?1) and from 0.19 to 0.75 μg L^?1 (kg^?1), respectively. The procedure has been accredited and successfully applied as a screening method for the presence of hormone residues in the study of commercial samples of milk.     

A Micro-Flow-Batch Analyzer Using an In-line Cadmium Sponge Microcolumn for the Photometric Determination of Nitrate and Nitrite in Dairy Samples

In this study, a micro-flow-batch analyzer (μFBA) using an in-line cadmium reduction microcolumn for the photometric determination of nitrate and nitrite in dairy samples is described. The method is based on the Griess-Llosvay reaction and measuring of the absorbance at 540 nm using a green LED integrated into the μFBA built in the urethane-acrylate resin. Initially, the nitrite content of the dairy sample is analyzed in the mixing chamber, while the nitrate is reduced to nitrite in cadmium sponge microcolumn coupled to the microsystem. Nitrate content was calculated from the difference between nitrate plus nitrite (expressed as nitrite) and nitrite content. The analytical curve for nitrate and nitrite was linear in the work range of 10.0–100.0 μg L^?1 with a correlation coefficient of 0.992 and 0.998, respectively. The limit of detection and relative standard deviation were estimated at 0.39 μg L^?1 and <1.7 % (n?=?5) for nitrite and 0.41 μg L^?1 and <1.3 % (n?=?5) for nitrate. Comparing with the reference methods, no statistically significant differences were observed when applying the paired t test at a 95 % confidence level. The accuracy was assessed through recovery test (97.7 to 102.9 %). The proposed microsystem-employed in-line cadmium sponge microcolumn presented satisfactory portability, robustness, flexibility, low-cost device, and reduced chemicals consumption compared to recent methods. Thus, μFBA is potentially useful as an alternative for other automatic determinations using in-line pretreatment steps.