Transcript Nabil A. Fakhre

Quality Control of Some Water, Food,
and
Drug Samples in Erbil City, Iraq
Prof. Dr. Nabil A. Fakhre
Dept. of Chemistry, College of Education/
Scientific Depts., Univ. of Salahalddin,
Erbil, IRAQ
[email protected]
Qualitycontrol (QC) is a procedure or set of procedures intended to ensure that
a manufactured product or performed service adheres to a defined set of
quality criteria or meets the requirements of the client or
customer.
This global quality management system provides the basis for analyzing
customer requirements, defining theprocesses that contribute to the
achievement of a productor service that is acceptable to the customer,
and provisions for keeping these processes in control.
QC activities include general methods such as accuracy checks on data
acquisition and calculations and the use of approved standardized
procedures for emission calculations, measurements, estimating
uncertainties, archiving information and reporting.
Higher tier QC activities include technical reviews of source categories, activity
and emission factor data, and methods.
SEMI-AUTOMATED DETERMINATION OF NITARATE IN TAP WATER SAMPLES USING
DIZOTIZATION- COUPLING REACTION
Nabil A. Fakhre, and Hemen A. Kadir
Nitrate is an important intermediate in the biogeochemical cycling of nitrogen in natural water. Because of the
relative stability of the nitrate ion, most nitrogenous materials in environmental media tend to be converted
to nitrate. Therefore, all sources of nitrogen (including organic nitrogen, ammonia and fertilizers) should be
considered as potential sources of nitrate. Nitrate is relatively non-toxic, and it can be converted readily by
bacteria to nitrite, which is also one of the pollutants in the atmosphere and natural water. Nitrate, converted
to nitrite, may reacted with amines (proteins found in some foods, medications, and water) to produce
nitrosamines, which have been found to be carcinogenic in animals. Some of types of cancer linked to this
reaction.
The maximum contaminated level for nitrate in drinking water is 45 ppm, and the value of total nitrogen at the
outlet of wastewater plant or in rivers and lakes should be below 18 ppm, which equivalent to about 59 ppm
of nitrite and 79.7 ppm nitrate.
Semi- automated method has been investigated for the determination of nitrate depending upon the reduction of
nitrate to nitrite using a mini-column of amalgamated cadmium redactor. The produced nitrite was reacted
with N, N-dimethyl-p-phenylenediamine dihydrochloride (NDMPDAH), to produce a water soluble, colorless
diazonium ion, which subsequently coupled with resorcinol to form an azo dye in the alkali medium to be
detected in a spectrophotometer with a flow cell of 30 ul. Nitrate was determined in the concentration range
(0.3- 6.0) ppm with detection limit 0.15 ppm and sampling rate of 60 samples/h.
The method is with acceptable precision and accuracy depending upon the values of relative standard deviation
and relative error percentage. The effect of 35 cations and anions on the determination of nitrate was
studied. To eliminate the influence of some cations two methods have been used; column of cationic
exchanger and EDTA solution.
The method was applied successfully for determination of nitrate in various wastewater samples in different
locations in Erbil City after the removal of turbidity, oil and grease. The results were compared to those
obtained with standard NEDA method.
Extraction-Spectrophotometric Determination of Nitrate in Polluted Water and Soil
Samples using Diazo-Coupling Reaction
Chinar M. Rasheed and Nabil A. Fakhre*
Department of Chemistry, College of Education, University of Salahalddin, Erbil, Iraq
Abstract
A simple and sensitive spectrophotometric method was described for the determination of
nitrate. The method is based on the reaction of nitrite with 3-amino-5-methyl isoxazole to form
a diazonium ion, which is coupled with resorcinol in an alkaline medium to form the azo dye,
with a maximum absorption at 354 nm. Nitrate is determined by it’s reduction to nitrite using
amalgamated cadmium column. Beer’s law is obeyed over the range of 0.04-6 g/ml, with a
detection limit of 0.02g/ml. The molar absorptivity, Sandell index are 2.482 x 104 L/mol.Cm
and 0.00249 g/ml respectively . The effect of 35 cations and anions were studied. The
method was applied for determination of nitrate in polluted water and soil samples, the results
were compaired with the standard method, NEDA. The prepared azo dye was extracted into 1:1
(v/v) mixture of isoamyl alcohol-isobutyl methyl ketone. Nitrate was determined over the range
of 0.005-2 g/ml with a detection limit of 0.003 g/ml and molar absorptivity 6.486 x 104
L/mol. cm.
Spectrophotometric Determination of Nitrite in Curing Meat Samples
Nabil A. Fakhre and Hemn A. Qader
Nitrite ion is an important intermediate in biological nitrogen cycle and is present in soils and
surface waters. Nitrite is also a versatile chemical agent, which has found numerous
applications ranging from dye manufacture to food preservation. Alkali nitrites and nitrates,
along with sodium chloride have long been used in the curing of meat products to prevent
bacterial spoilage and to enhance the flavor, color and texture of these food products. Nitrite
oxidizes hemoglobin to methemoglobin, which is unable to transport oxygen, and nitrites react
with amines and amides to form nitrosamines, which are potent carcinogens. Current legislation
(EU Directive 95/2) suggests maximum amounts to be added at the beginning of processing in
various meat products and imposes a maximum residue of 50 μg/ml nitrites and 250 μg/ml
nitrates in cured meat products that have not been thermally treated.
The nitrite content in meat products has been regulated and the majority of the analytical methods
recommended by the legislations of different countries to determine its content are based on
the Saltzman modification of the classical Griees method. Many methods have been reported
for the spectrophotometric determination of nitrite .
In the present work, a simple procedure for the spectrophotometric determination of nitrite is
described. The method is based on the reaction of acidified 2-aminobenzoimidazole as the
diazotizing agent with nitrite to produce water solublediazoniumion, which subsequently
coupled with orcinol to give azo dye having maximum absorption at305nm. The method has
been successfully applied to the determination of nitrite in curing meat samples.
DETERMINATION of ACRYLAMIDE in POTATO CHIPS SAMPLES USING DIFFERENT ANALYTICAL
TECHNIQUES
Nabil A. Fakhre and Bnar M. Ibrahim
Chemistry Department, College of Education /Scientific Departments,University of Salahaddin, Erbil / Kurdistan
Region, Iraq
[email protected]
Acrylamide is formed in some foods cooked at high temperature (120-170ºC) by the reaction of the amino
acid asparagines with a reducing sugar such as glucose. Acrylamide is genotoxic and carcinogenic in studies
in animals. It causes increased tumour incidence at a variety of sites. The international agency on research
on cancer has classified acrylamide as probably carcinogenic to humans. Two sensitive and fast batch and
flow-injection spectrophotometric methods for the determination of acrylamide are proposed. The methods
were based on oxidation-reduction reaction of acrylamide with potassium permanganate. The calibration
graphs are linear over the ranges 1.0–8.0 and 2.0-13µg/ml of acrylamide, with detection limits of 0.6 and
1.0µg/ml, respectively. The methods are applied to the routine analysis of acrylamide in potato chips
samples. It confirms that the analytical procedure employed for the analysis is suitable and reliable for its
intended use. Acrylamide was also determined in the presence of glucose and asparagines. Reduction of
some cationic interference was carried out in the batch and flow injection analysis using cationic exchanger
of hydrogen form with 2.5 –mm internal diameter, 15-cm length of packing and flow rate 0.5 ml/min. The
proposed first and second derivative methods for determination of acrylamide, are simple, rapid (as it only
requires measurements of nD values at a single wavelength). They were used for identification of the
acrylamide depending upon characteristic peaks at certain wavelengths or ranges. The first and second
derivative spectra of the mentioned compound have been used for determination of the compounds at
different ranges of concentration depending upon the measurements of the heights of the peak to the
baseline at certain wavelengths. HPLC was used as a standard method for qualification and quatitation of
acryl amide in different potato chips samples, and the results obtained were agreed with those of the
proposed methods.
On–line separation and preconcentration for histamine determination
in fish meal using cation– exchanger resin
Nabil A. Fakhre and Mohammad S. Abdulla
Biogenic amines are a group of biologically active organic compounds normally
produced by decarboxylation of free amino acids. Biogenic amines are present in a
variety of foods and have been widely documented as occurring in fish and fish
products, meat, wine, cheese and fermented foods. The presence of biogenic amines
in these foods is an indication of food spoilage which is dependent upon the
availability of free amino.
Histamine, which is the most important biogenic amine, can cause poisoning as a result
of the ingestion of food containing high levels of this amine.
To a series of 25 ml volumetric flasks, 4.0 ml of 0.2% p-toluidine (prepared in 0.5M
HCl), 0.5 ml of 0.5% sodium nitrite, 12.5 to 175 μg of histamine and 2.0 ml of 1M
KOH were added. The solution completed to mark with ethanol after two minutes.
Absorbance measurements were carried out against reagent blank. Fig. 2-2 shows
FI manifold used for histamine determination. A multi channel peristaltic pump was
used for propelling p-toluidine (0.5% in 1M hydrochloric acid) solution, 0.5% sodium
nitrite solution and 1M potassium hydroxide solution, with flow rates 0.9, 0.8 and 0.4
ml/min for solutions respectively. A 175 μl of histamine sample was injected through
the injection valve. Three reaction coils were used in the system with lengths 5cm
(RC1), 40cm (RC2) and 40cm (RC3). The merged streams were passed through a
quartz flow cell (30 μl, 10 mm path length) in a spectrophotometer.
FlOW-INJECTION SPECTROPHOTOMETRIC DETERMINATION OF
CHLOROGENIC ACID IN SOME NATURAL SAMPLES
Nabil, Adil Fakhre and Rizgar Mohamad Hassan
Polyphenols, are a group of chemical substances present in plants which play an important role during enzymatic
browning. They are responsible for the color of many plants, such as apples; part of the taste and flavor of
beverages (apple juice, tea). Chlorogenic acid (CGA) is a major phenolic natural product isolated from the
leaves and fruits of dicotyledonous plants, including the coffee beans which typically contain 5-8% of CGA.
Biologically, it is an important polyphenol; it is found widely in plants, black teas, soya beans, wheat, apple
juice, tobacco, some traditional Chinese medicines, beers, wines, Chinese herbs2 and accounting for > 75%
of the total phenolic acids content extracted from the eggplant sample, also the presence of CGA in
sunflower seeds is well-known.
CGA not only has the function of antioxidation, inhibiting hypertension and stimulating the flowering of plants, but
also affects the activity of trypsin, amylase and other enzymes. CGA is the main component producing the
bitter taste in crude coffee and thus deliberative elimination of CGA into the instant coffee has been adopted
extensively to improve the taste of various kinds of coffees. The contents of CGA in different areas and in
various foods are also quite different. Therefore, it is very important to establish some quantitative methods
to monitor the concentration of CGA in all kinds of real samples.
A flow-injection spectrophotometric system was applied for determination of chlorogenic acid using 3-amino-5methylisoxazole as diazotizing agent in the linear range of 1.0-50.0 g/ml, with the sample volume of 175 µl
and the detection limit of 0.30 g/ml. The rate of sampling was 60 samples/h, with the RSD% and Error% of
2.254% and + 3.4966%, respectively. The influences of seventeen phenolic compounds (as interferences)
such as dopamine, tyrosine, catechol, tannin, 2, 4-dihydroxybenzoic acid, caffeic acid and p-cresol on
determination of chlorogenic acid were studied. An ultrasonic technique was used for extracting chlorogenic
acid in the samples by using 80% (v/v) methanol aqueous solution. The proposed method was successfully
applied for the determination of chlorogenic acid content in various natural samples such as grape, tobacco
and black tea.
Studies on Physico - Chemical Characteristics of Some Edible Oils
and
Authentication of Triacylglycerols using HPLC
Nabil A. Fakhre and Hemen K. Kadir
The aim of the study


It is intended to study the properties of some of edible oil
samples through the phsico - chemical tests like (refractive
index, specific gravity, viscosity, iodine value, peroxide value,
percentage of free fatty acid and pH value). The study aims
to shed more light on the oil acidity and composition of
saturated and unsaturated fatty acids.
The adulteration was the second aim of the present study
using (RP-HPLC/RI detector) to confirm authenticity of
triacylglycerols and to identify the composition of blends of
some edible vegetable oils.
FLOW-INJECTION AND STOPPED FLOW SPECTROPHOTOMETRIC DETERMINATION OF
DOPAMINE HYDROCHLORIDE IN PHARMACEUTICAL PREPARATIONS
Nabil A. Fakhre, and Mohamad S. Abdullah
Dept. of Chemistry, College of Science Education, Univ. of Salahaddin, Erbil, IRAQ.
[email protected]
Key words: Flow-injection, Stopped flow, Spectrophotometric determination,
Dopamine.
The catecholamines participate in the regulation of a wide variety of physiological
function in humans. In principle they control cardiac output and apportion blood
flow. Dopamine is one of most significant catecholamines. It is naturally occurring
amine used for treatment of acute congestive failure and renal failure. Dopamine
hydrochloride is determined by flow injection and stopped-flow. The assay depends
on the nitrosation of the aromatic ring followed by forming a stable colored
compound in alkali medium. The reaction has a maximum absorption at 377nm. The
method obeyed Beer´ s law in the range 40-160µg/ml. The number of sample
throughput is 35s/hour with injected sample 200µl. To increase the sensitivity of the
method stopping flow of the reaction zone in the flow cell at a regulated time after
the injection of sample was made. The optimum time of stopping was 60 sec. The
method obeyed Beer´ s law in the range 15-120 µg/ml. Both methods were applied
for determination of dopamine hydrochloride in pharmaceutical preparation with
recoveries 95.0-97.0%.
Flow injection Spectrophotometric Determination of Folic Acid in Some
Pharmaceutical Preparations using Diazotizing-Coupling Method
Nabil Adil Fakhre and Mohammad Salim Abdullah
Folic acid (FA) is extremely important vitamin that occurs naturally in foods. It is
essential for human. Folacin is a generic name covering FA and related compounds
having the same biochemical activities of FA. Folic acid and folate (the anion form)
are forms of water soluble B-vitamins ( Champe and Harvey,1994). It plays a key
role in one-carbon metabolism, and is essential for the biosynthesis of the purines
and pyrimidines. Folic acid deficiency is probably the most common vitamin in USA,
particularly among pregnant women and alcoholism ( Marks et.al,1996) . Folic acid
helps form building blocks of DNA, the body genetic information, and building
blocks of RNA, needed for protein synthesis in all cells.
The present study describes a simple, rapid and sensitive method for the determination
of folic acid at 435nm. Folic acid was diazotizated with nitrous acid then coupled with
sulphanilic acid. Nitrous acid (0.5% NaNO2 in 0.5M HCl), 0.1% sulphanilic acid and
0.25M sodium hydroxide solutions were propelled at flow rates 0.6ml/min. Folic acid
solution (10μg/ml) was injected with sample volume 125μl to react with the nitrous
acid solution in a reaction coil of 10-cm. The proposed flow system method was
linear in the range 6.0 to 25.0 µg/ml. The precision and accuracy of the methods
were checked. The effects of foreign species were tested. The proposed method was
successfully applied to the determination of folic acid in commercial folic acid tablets.
The results are compared with that of standard method (HPLC).
Determination of Gasoline and Kerosene in a Mixture Using Peak-to -Peak
Derivative Spectroscopic Method
Nabil A. Fakhre
Although UV-visible spectra do not enable absolute identification of an unknown 
substance, they frequently are used to confirm identity through comparison of the
measured spectrum with a reference spectrum. Typical multispectral analysis
methods treat each spectral band as an independent variable, a reasonable
assumption for multispectral data but not really appropriate for hyperspectral data.
In spectroscopy, particularly in infra-red, UV and visible absorption, fluorescence,
and reflectance spectrophotometry, differentiation of spectra is a widely used
technique, referred to as derivative spectroscopy. Derivative spectroscopy has the
potential of greatly increasing the application of UV-visible spectroscopy. Derivative
methods have been used in analytical spectroscopy for three main purposes, spectral
discrimination, spectral resolution enhancements, and quantitative analysis.
Therefore, a simple and rapid method is described for the simultaneous quantitative
analysis of gasoline and kerosene in a mixture using first, second, third and fourth
derivative spectroscopy. Peak-to-peak heights were used to find various
concentration ranges of gasoline and kerosene. First derivative spectra were used for
determination of 10-60% and 40-80% Gasoline and 40-90% and 20-60% kerosene.
Whereas second and third derivative spectra have been used for determination of
40-80% gasoline and 20-60% kerosene. Fourth derivative spectra were used for
determination of 20-80% gasoline and kerosene.
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