Validation of a quick and effective method for determining nitrate
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Brazilian Journal of Development 3416
ISSN: 2525-8761
Validation of a quick and effective method for determining nitrate and
nitrite in meat products
Validação de método rápido e eficaz para determinação de nitrato e
nitrito em produtos cárneos
DOI:10.34117/bjdv7n1-230
Recebimento dos originais: 08/12/2020
Aceitação para publicação:11/01/2021
Liliane Fernandes dos Santos
Graduada em Engenharia de Produção
Instituição: Fundação Ezequiel Dias - FUNED
Rua Conde Pereira Carneiro, 80, Bairro Gameleira, CEP 30510-010, Belo Horizonte,
Minas Gerais, Brasil.
E-mail: liliane.santos@funed.mg.gov.br
Priscila Alves Lima
Especialista em Farmacologia
Instituição: Fundação Ezequiel Dias - FUNED
Rua Conde Pereira Carneiro, 80, Bairro Gameleira, CEP 30510-010, Belo Horizonte,
Minas Gerais, Brasil
E-mail: priscila.lima@funed.mg.gov.br
Cláudia Aparecida de Oliveira e Silva
Doutora em Ciência de Alimentos
Instituição: Fundação Ezequiel Dias - FUNED
Rua Conde Pereira Carneiro, 80, Bairro Gameleira, CEP 30510-010, Belo Horizonte,
Minas Gerais, Brasil
E-mail: claudia.aparecida@funed.mg.gov.br
Pedro Henrique Cabral de Souza
Graduado em Engenharia Química
Instituição: Universidade Federal de Minas Gerais – UFMG
Rua Basilicata, 338, Bairro Bandeirantes, Belo Horizonte, Minas Gerais, Brasil.
E-mail: pedrohc.souza@gmail.com
Flávio Rodrigues Pereira
Especialista em Controle da Qualidade em Vigilância Sanitária
Instituição: Fundação Ezequiel Dias - FUNED
Rua Conde Pereira Carneiro, 80, Bairro Gameleira, CEP 30510-010, Belo Horizonte,
Minas Gerais, Brasil
E-mail: flavio.rodrigues@funed.mg.gov.br
Gizele Barrozo Ribeiro
Graduada em História
Instituição: Fundação Ezequiel Dias - FUNED
Rua Conde Pereira Carneiro, 80, Bairro Gameleira, CEP 30510-010, Belo Horizonte,
Minas Gerais, Brasil.
Brazilian Journal of Development, Curitiba, v.7, n.1, p. 3416-3429 jan. 2021Brazilian Journal of Development 3417
ISSN: 2525-8761
E-mail: gizele.ribeiro@funed.mg.gov.br.
Cristiane Lúcia Goddard
Mestra em Ciência de Alimentos
Instituição: Fundação Ezequiel Dias - FUNED
Rua Conde Pereira Carneiro, 80, Bairro Gameleira, CEP 30510-010, Belo Horizonte,
Minas Gerais, Brasil.
E-mail: cristiane.goddard@funed.mg.gov.br
Sara Araújo Valladão
Mestra em Ciência de Alimentos
Instituição: Fundação Ezequiel Dias - FUNED
Rua Conde Pereira Carneiro, 80, Bairro Gameleira, CEP 30510-010, Belo Horizonte,
Minas Gerais, Brasil.
E-mail: sara.valladao@funed.mg.gov.br
ABSTRACT
In order to implement quick and low residues assays, reflectometry methods for nitrate
and nitrite quantification in meat products were validated. Measurement uncertainties
were estimated and the methods were applied in commercial samples. The established
work range for nitrate determination was 0.007 to 0.188 g/100g expressed in NaNO2.
Limits of detection and quantification were 0.0042 and 0.0067 g/100g, respectively.
Recovery results were between 90 and 115%, and the precision between 4.1 and 12.8%.
The method revealed itself selective in the presence of interferers, except for nitrites, what
made necessary its previous elimination. The relative expanded uncertainty varied
between 5.3 e 14.2%. The method’s repeatability was the greatest source of contribution
for the uncertainty. The established work range for nitrite determination was 0.0056 to
0.028g/100g expressed in NaNO2. Limits of detection and quantification were 0.0009
and 0.0056 g/100g. Recovery results were between 81 and 85%, and precision between
4.4 and 10.8%. Phosphates (0.5 g/100g) and ascorbic acid (0.01 g/100g) were evaluated
as interferes. Expanded relative uncertainty varied between 2.9 and 4.9%. The methods
turned out simple, quick and suitable for the analyte’s quantification. Applying the
methods in commercial samples, satisfactory results according to maximum limits
established by the law were obtained.
Keywords: Food aditives, Food preservatives, Health Risk, Analytical Methods,
Validation Study.
RESUMO
Buscando implementar ensaios rápidos e com menor geração de resíduos, foram
validados métodos reflectométricos para quantificar nitratos e nitritos em produtos
cárneos. As incertezas de medição foram estimadas e os métodos foram aplicados em
amostras comerciais. Na determinação de nitratos a faixa de trabalho estabelecida foi de
0,007 a 0,188 g/100g expressos em NaNO2 com limites de detecção e quantificação
práticos de 0,0042 e 0,0067 g/100g, respectivamente. Obteve-se recuperações entre 90 e
115% e precisão entre 4,1 e 12,8%. O método mostrou-se seletivo ao analito na presença
de interferentes, exceto nitritos, sendo necessária sua eliminação prévia. A incerteza
expandida relativa variou entre 5,3 e 14,2%, sendo a repetibilidade do método a maior
fonte de contribuição. A faixa de trabalho para nitritos foi de 0,0056 a 0,028 g/100g
Brazilian Journal of Development, Curitiba, v.7, n.1, p. 3416-3429 jan. 2021Brazilian Journal of Development 3418
ISSN: 2525-8761
expressos em NaNO2, com limites de detecção e quantificação práticos de 0,0009 e
0,0056 g/100g, respectivamente. Obteve-se recuperações entre 81e 85% e precisão entre
4,4 e 10,8%. Fosfatos (0,5 g/100g) e ácido ascórbico (0,01 g/100g) foram identificados
como interferentes do método. A incerteza expandida relativa variou entre 2,9 a 4,9%. Os
métodos mostraram-se simples, rápidos e adequados para a quantificação dos analitos.
Na aplicação dos métodos em amostras comerciais, obteve-se resultados satisfatórios
conforme limites máximos estabelecidos pela legislação.
Palavras-chave: Aditivos alimentares, Conservantes de alimentos, Risco à saúde,
Métodos analíticos, Estudos de validação.
1 INTRODUCTION
Brazil is a great meat producer and consumer, and it exports its products to many
countries around the world. In 2016, 24.30 millions of tons of bovine, pork and chicken
meat of were produced (IBGE, 2017).
Perishable industrialized food present short durability due to the presence of
favorable conditions for the microbial development, which may make the product
improper for consuming. Sodium and potassium nitrates and nitrites are additives widely
used in the food industry as preservatives, and they highlight food’s color and the flavor
(MIDIO & MARTINS, 2000).
However, the consumption of food that contains these additives may be harmful,
once they present acute and chronic toxic effects to the individuals. The risks to the human
health due to the toxicity are quite discussed. Nitrates may be harmful, because they can
be converted into nitrites. Effects like hypertension have been correlated to high exposure
to nitrites. Nitrites are metemoglobinizers, which means they offer risk to early childhood
children. These ions form N-nitroses compounds, which may be carcinogenic, by the
reaction with secondary and tertiary amines, amides and amino acids (BRUNING-FANN
& KANEENE, 1993; MIDIO & MARTINS, 2000).
In Brazil, the National Sanitary Surveillance Agency –ANVISA and the
Agriculture, Livestock and Supply Ministry – MAPA, have established maximum
allowed values for the use of these preservatives in meat products. The values are 0.015
g/100g e 0.030 g/100g of the product, respectively for nitrite and nitrate, expressed in
terms of NaNO2 (BRASIL, 2006; BRASIL, 2019). The Food and Drug Administration –
FDA establishes the limits for nitrites e nitrates at 0.020 e 0.050 g/100g, respectively, for
the consumption products (FDA, 2017). The European Union – EU establishes limits for
nitrates and nitrites that, according to the kind of processing, vary between 0.005 and
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ISSN: 2525-8761
0.0175 g/100g for nitrites and between 0.001 to 0.030 g/100g for nitrates (EC, 2008).
The Brazilian official method for the nitrites quantification in meat products is
based in the diazotization of nitrites by sulfanilic acid and the copulation with alfa-
naftilamine hydrochloride in acid environment, forming alfa-naftilamine-p-azobenzene-
p-sulfonic acid, which presents a pink color that can be determined
spectrophotometrically at 540 nm. For nitrates, the method is based in the reduction of
nitrate to nitrite by the addition of spongy Cadmium in alkaline environment, following,
then, the same steps for the nitrite method. Total nitrite is quantified and, by the difference
in relation to the initial nitrite content, the nitrate content is quantified (BRASIL, 1999).
The normalized methods for the determination of these analytes recommended by the
Association of Official Analytical Chemists – AOAC are also based in longstanding and
toxic spectrophotometric techniques (AOAC, 2016).
The reagents toxicity is a great issue of the official or normalized methods.
Sulfanilamide, frequently used in these tests, is a carcinogenic substance and may cause
allergic reactions. Many methods that replace toxic reagents are cited in literature
(MELCHERT, 2005) and the direct manipulation of these reagents by the analysts can be
avoided by using analysis kits. Time spent in the analysis also is a limiting factor.
Traditional methods may take around 2 to 3 days.
Instrumental methodologies that use flow injection with spectrophotometric
detection, capillary electrophoreses and ionic chromatography have been developed as an
alternative for determination of nitrates and nitrites. Meantime, the used equipments are
expensive, require especial maintenance and there is no enough specialized labor
(ANDRADE, 2004; BETTA, 2016; LÓPEZ-MORENO et al., 2015).
Given the importance of monitoring the content of nitrates and nitrites in food,
and the necessity of implementing methodologies with lower residues and toxicity,
greater quickness and simplicity, still ensuring analytical reliability, this work’s intent
was to validate and apply nitrates and nitrites quantification methods in meat products by
reflectometry using kits.
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2 MATERIAL AND METHODS
2.1 NITRATE AND NITRITE DETERMINATION
The assays were done at the Chemistry Service’s Bromatological Chemical
Laboratory (LQB) of the Octávio Magalhães Institute (Minas Gerais Public Health
Central Laboratory/LACEN-MG), Ezequiel Dias Foundation.
The used methods are based on the reduction of nitrate ions to nitrite by the action
of a reducer reagent. The nitrite ions, in the presence of an acid tampon, form a diazonium
salt with aromatic amines. This salt reacts with N-(1-naftil)-ethylene diamine, resulting
in red-violet azo dye. This dye content was reflectometrically determined using a digital
equipment, RQFlex® - Reflectoquant Plus 10 (Merck), and the Reflectoquant® Nitrate
Test n°1.16971.0001 kits (range from 5 to 225 mg/L, what corresponds to 0.0006 to 0.028
g/100g of NaNO2). All of the used reagents were impregnated in reactive stripes, what
excluded the necessity of their previous prepare and manipulation (MERCK, 2013a;
MERCK, 2013b; MERCK, 2016).
The application of MERCK-Millipore Method – Nitrite in Meat Products, from
2012-07-11, was the sample preparation and analyte extraction used methodology
(MERCK, 2012). 20 grams of the sample were solubilized in 150 mL of purified water.
The mixture was then agitated by a homogenizer at 380 rpm and heated to 80 ºC. The
sample was filtrated in analytical filter paper and cooled down to room temperature for a
posterior reflectometer analysis.
The kit’s reactive strip was immerged in the sample extract for 2 seconds and put
perpendicularly upon the absorbing paper for withdraw of excess fluid. In the nitrite
determination, the strip was immediately inserted in the equipment. In the nitrate
quantification method, the strip was inserted 10 seconds before the beginning of the
reaction time (15 and 60 seconds for nitrites and nitrates, respectively). Then, the result,
in mg/L, could be directly read at the equipment screen. The gotten value was converted
to g/100 g of NaNO2 (MERCK, 2013b; MERCK, 2016).
2.2 SINGLE LABORATORY VALIDATION
The method was single laboratory validated using stock solutions of sodium
nitrate and nitrite in in natura meat samples with and without the addition of analyte.
Selectivity, recovery, precision in repeatability conditions, intermediate precision, limits
of detection (LOD) and quantification (LOQ) were investigated in accordance with
guidance documents about methodology validation (EURACHEM/CITAC, 2012;
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INMETRO, 2017). The calculation and statistical analysis were done using a Microsoft
Excel 2010 spreadsheet.
2.2.1 Selectivity
For the determination of nitrites, the selectivity was evaluated by analyzing the
fresh meat sample added with nitrates or nitrites in the absence and presence of the
possible interfering agents (ingredients or additives permitted for use in meat products):
sodium phosphate (0.50 g / 100 g), ascorbic acid (0.01 g / 100 g) and sodium nitrate (0.03
g / 100 g). For nitrates, the phosphate was evaluated at the same concentration, ascorbic
acid (0.10 g / 100 g) and sodium nitrite (0.01 g / 100 g). It is noteworthy that, for the
nitrate, there already is an indication of methodology of the manufacturer on the necessity
of removal of the nitrites for the quantification of this one. The averages obtained in each
treatment were compared by analysis of variance - F test (α = 0.05). White sample reading
was performed to evaluate matrix interference.
The method for elimination of nitrite interferer has also been tested for its efficacy.
Triplicate tests were carried out to eliminate nitrites at a concentration of 0.01 g / 100g
by adding 5 drops of the 10% sulfamic acid solution to 5 ml of the sample prepared
according to the procedure described by the manufacturer, containing nitrates at the
concentration of 0.03 g / 100g. The evaluation was carried out by measuring the nitrate
and nitrite concentrations by the two methodologies, before and after the addition of
sulfamic acid.
2.2.2 Accuracy and precision
Nitrate (NO3-) stock solutions were prepared at concentrations of 10, 20 g/L,
nitrite (NO2-) at concentrations of 1 and 10 g/L for addition in the samples, from the
reagents sodium nitrate, and nitrite with minimum purity of 99%.
The accuracy and precision were evaluated in three concentration levels (N1, N2
and N3), covering the work range and values established by current legislation (0.03
g/100 g nitrate and 0.015 g/100 g nitrite, both expressed in NaNO2). The samples were
fortified to obtain the concentrations of 0.007, 0.030 and 0.188 g / 100 g of nitrate and
0.006, 0.015 and 0.028 g / 100 g of nitrite, expressed as NaNO2. The calculation described
in Equation 1, obtained from the used methodology (MERCK, 2012), was applied to the
readings in mg/L for conversion of the results to mg / kg.
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Nitrate or Nitrite [mg/kg] = (measured value [mg/L] x 150 [mL]) / weight of sample [g]
(1)
The recoveries were estimated for each concentration level, after the exclusion of
outliers. Precision, under conditions of repeatability and intermediate precision (only for
the median levels) were estimated by analysis of variance and expressed in terms of
relative standard deviation of repeatability (RSDr) and relative standard deviation of
reproducibility (RSDR). HorRat ratios were obtained by dividing Calculated RSD’s and
reference values. Ratios below 2.0 were considered satisfactory (INMETRO, 2017).
2.2.3 Measure range and limits of detection and quantification
The theoretical limits of detection and quantification were evaluated by analyzing
samples containing low analyte contents (0.0023 g/100g for nitrites and 0.007g/100g for
nitrates, expressed as NaNO2). They have been defined as 3 and 10 times the standard
deviation, respectively (INMETRO, 2017).
Practical limits of quantification were experimentally determined by the precision
and accuracy evaluation for low concentrations of analyte, defined from the theoretical
limits obtained and the work range of the kit (INMETRO, 2017).
2.3 ESTIMATION OF MEASURE UNCERTAINTY
The measure uncertainty estimation (U) was determined according to
EURACHEM / CITAC (2012), for the same concentrations studied in the precision, in
order to know the interval (Xlab ± Ulab). The uncertainty sources of the methods were
defined and the equations necessary to obtain the uncertainties for a confidence level of
approximately 95% were applied.
2.4 APPLICATION OF VALIDATED METHODOLOGIES
The validated methods were applied to five commercial samples of meat products
(Calabrian sausage, smoked pork sausage, cooked and smoked pork sausage, fresh pork
sausage and fresh filet). These samples were collected by the Sanitary Surveillance of
Minas Gerais, complying with consumer denouncing reports or with programs to monitor
the marketed food quality in the state.
The nitrite analyzes were performed prior to the nitrate analysis, so that when
detected or quantified were withdrawn through the method specified in the package insert,
not interfering with the obtained results in nitrate quantification.
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The results obtained were compared to the maximum permitted values (MPVs) by
current legislation (BRASIL, 2019; BRASIL, 2006).
3 RESULTS AND DISCUSSION
3.1 SELECTIVITY
Using the analysis of variance method and the ANOVA table, the results of tables
1, 2 and 3 for the interference of the phosphate, ascorbic acid, nitrate and nitrite additives
were obtained. Kits presented a reading lower than the detection limit for the white matrix
and for the matrix with the addition of all interfering agents, except for the nitrite, whose
presence resulted in a reading greater than the detection limit. The nitrite, as indicated in
the package insert, is an interferer in the test when detected alone in the sample at the
concentration of 0.05 g/100g (Table 1).
In the determination of the nitrate content, interference of nitrite (potentiating
effect) has been verified, raising nitrate concentration to 0.076 g / 100g. Therefore, it was
confirmed the necessity of the previous elimination of this ion for the determination of
nitrates in meat products (Table 2).
Table 1. Effect of interfering agents on the NO2 and NO3 quantification in a matrix without the analyte of
interest.
Interfering agent Addition in the matrix (g/100g) Result (g/100g expressed in NaNO2)
Nitrite analysis
Control sample - < LOD
Nitrates 0.030 < LOD
Ascorbic acid 0.010 < LOD
Phosphates 0.500 < LOD
Nitrate analysis
Control sample - < LOD
Nitrites 0.015 0.05
Ascorbic acid 0.100 < LOD
Phosphates 0.500 < LOD
LOD: limit of detection.
Table 2. Effect of interfering agents on the NO 3 quantification in fortified matrix.
Addition in the matrix Nitrates addition in the Result
Interfering agent
(g/100g) matrix (g/100g*) (g/100g*)
Control sample - 0.030 0.027a
Nitrites 0.010 0.030 0.076b
Ascorbic Acid 0.100 0.030 0.024a
Phosphates 0.500 0.030 0.024a
Nitrites + sulfamic acid (10%) 0.010 0.030 0.025a
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*expressed in NaNO2; aaverages in a single column followed by the same letter do not differ between each
other by the F test at the 5% probability level.
The effectiveness of the pretreatment with sulfamic acid for removal of nitrites
has also been verified, since there was no significant difference between the averages of
the samples added only of nitrate and of nitrate and nitrite with previous treatment.
In the nitrite content determination, the matrix added of this analyte in the
presence of the interferers, phosphate and ascorbic acid presented potentiating effect in
the evaluated concentrations of 0.50 g/100g and 0.10 g/100g expressed in NaNO2,
respectively (Table 3).
Since the commercial samples may or may not have the interfering agents in their
composition and they may be in different concentrations, once there is no maximum value
established by current legislation, the finding of interference in the studied concentrations
suggests the need for previous removal of the interferers in the samples. Evaluation of
analyte’s recovery in each sample to be analyzed may also be done, in order to guarantee
the non-occurrence of the overestimated determination of the nitrites.
Table 3. Effect of interfering agents to NO2 quantification in fortified matrix.
Addition in the matrix Nitrites in the matrix Result
Interfering agent
(g/100g) (g/100g*) (g/100g*)
Control sample - 0.015 0.012a
Nitrate 0.030 0.015 0.013a
Ascorbic acid 0.010 0.015 0.015b
Phosphate 0.500 0.015 0.015b
*expressed in NaNO2; a averages in a single column followed by the same letter do not differ between each
other by the F test at the 5% probability level.
3.2 ACCURACY AND PRECISION
The average recoveries for the nitrate and nitrite methods were satisfactory,
according to the acceptance criteria of 80 to 110% (INMETRO, 2017), except for nitrate
determination at the N1 level (0.007 g/100g expressed as NaNO2) with a recovery of
115% (Table 4).
The results were satisfactory considering that the calculated RSD were lower than
the reference RSD’s and the HorRat values were lower than 2.0 at all levels evaluated for
both repeatability and intermediate accuracy.
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Table 4. Relative standard deviation in repeatability conditions, intermediate precision and HorRat.
Repeatability IP
Value Recovery
Analyte Nf RSD r RSD r RSD R RSDR HorRatr HorRatR
(g/100 g*) (%)
calculated reference calculated reference
0.007 6 115 12.8 15.3 - - 0.8 -
-
NO3 0.030 12 90 4.1 6.3 8.3 9.5 0.6 0.9
0.188 6 94 9.0 9.5 - - 0.9 -
0.006 6 83 5.0 12.9 - - 0.4 -
NO2 0.015 12 81 5.0 7.5 7.4 11.2 0.7 0.7
0.028 6 85 4.4 6.7 - - 0.7 -
f
*expressed in NaNO2; IP: intermediate precision; N : Number of observations, after the Grubbs outlier
treatment; RSDr: Relative standard deviation, in repeatability conditions; RSD R: Relative standard
deviation, in conditions of intermediate precision; HorRat r: RSDr observed value divided by the reference
RSDr value, defined as 2/3 of RSDR estimated by the modified Horwitz or Thompson equations; HorRat R:
RSDR observed value divided by the RSDR value, estimated by the modified Horwitz Thompson equation.
The accuracy and precision in the studied concentrations were satisfactory. The
ranges from 0.007 to 0.188 g/100g of NO3- and 0.006 to 0.028 g/100g of NO2- were
established. Due to the recovery of 115% at the N1 nitrate level and the application in
meat products, it has been chosen to evaluate the recovery in each sample through
fortification and the correction of results above the established criteria.
3.3 MEASURE RANGE AND LIMITS OF QUANTIFICATION AND DETECTION
The theoretical limits of detection were 0.0029 g/100g for nitrates and 0.0006
g/100g for nitrites, both expressed as NaNO2. The lowest concentrations detected in
practice were 0.0042g/100g for nitrates and 0.0009 g/100g for nitrites, both expressed in
NaNO2, therefore considered practical limits of detection of the methods.
The theoretical limits of quantification were 0.0098 g/100g and 0.0018 g/100g
expressed as NaNO2, for nitrates and nitrites respectively. Practical limits of
quantification were 0.0056 g/100g and 0.0067g/100g for nitrites and nitrates,
respectively, both expressed as NaNO2 (Table 5).
It is worth mentioning that the limits obtained are contained in the measurement
range established by the manufacturer and that their concentrations are significantly
below the Maximum Allowable Value (MAV) for the addition of nitrates and nitrites in
meat products.
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Table 5. Theoretical e practical limits of quantification and detection in g/100g expressed in NaNO2.
Analyte Limits Theoretical Practical
LOD 0.0029 0.0042
NO3-
LOQ 0.0098 0.0067
LOD 0.0006 0.0009
NO2-
LOQ 0.0018 0.0056
LOD: limit of detection; LOQ: limit of quantification.
3.4 MEASURE UNCERTAINTY ESTIMATIVE
The measure uncertainty estimative varied between 5.31% and 14.15% for the
nitrate method and from 2.91 to 4.93% for nitrites (Tables 6 and 7). The uncertainty
source that contributed the most for the estimated uncertainty was the repeatability for
both the methods.
Table 6. Results of measure uncertainty estimative for the NO 3 method in g/100g expressed in NaNO2.
Theoretical Relative expanded Concentration +
Coverage factor (k)
concentration (g/100g) uncertainty (U %) uncertainty (g/100g)
0.007 14.15 2.32 0.007 ± 0.001
0.030 5.31 2.18 0.030 ± 0.002
0.188 9.84 2.65 0.188 ± 0.018
Table 7. Results of measure uncertainty estimative for the NO2 method in g/100g expressed in NaNO2.
Theoretical Relative expanded Coverage factor Concentration +
concentration (g/100g) uncertainty (U %) (k) uncertainty (g/100g)
0.0056 2.91 2.21 0.0056 ± 0.0002
0.015 4.66 2.23 0.015 ± 0.001
0.028 4.93 2.65 0.028 ± 0.001
For the measurement uncertainty information for the samples in the routine, it was
decided to consider the result of greater variation (4.93%), obtained for the N1 level of
0.006 g/100g for the study of nitrites. For the nitrate study, the following ranges defined
two uncertainty values: 0.007 to 0.029 g/100g - uncertainty of 14.15% and 0.030 to
0.188g/100g - uncertainty of 9.84%.
3.5 DETERMINATION OF NITRATES AND NITRITES IN COMMERCIAL MEAT
PRODUCTS SAMPLES
All the evaluated samples generated satisfactory results when compared to the
maximum limits established by the legislation (Table 8).
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Table 8. Results for the nitrate and nitrite content in the analyzed samples in 2017 expressed in NaNO2.
Sample Nitrates (g/100g) Nitrites (g/100g)
Pepperoni sausage (0.010 ± 0.001) < LOQ
Smoked pork sausage < LOQ < LOQ
Sausage of cooked and smoked pork (0.007 ± 0.001) < LOQ
Fresh pork sausage (shank) < LOQ < LOQ
Against filet < LOD < LOD
LOD: limit of detection; LOQ: limit of quantification.
4 CONCLUSIONS
The evaluated methods proved to be adequate and applicable for the determination
of nitrates and nitrites in meat products, presenting advantages over traditional methods,
like quickness, practicality and minimum generation of residues. It is important to
monitor the recovery and elimination of interfering agents in each case, especially in the
determination of nitrates.
According to the values obtained in the tests, the samples are within the
parameters permitted by legislation. The samples had nitrate contents between 0.007 and
0.01 g/100g and did not present quantifiable nitrite contents.
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ANDRADE, R. (2004). Desenvolvimento de métodos analíticos para determinação de
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