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ABSTRACT: Data on the distribution of dissolved inorganic carbon (DIC) were obtained from two cruises in the North Yellow Sea (NYS)
and off the Qingdao Coast (QC) in October, 2007. Carbonate parameters were calculated. The concentrations of DIC are from
1.896–2.229 mmolL−1 in the NYS and from 1.939–2.032 mmolL−1 off the QC. In the southwest of the NYS, DIC in the upper layers decreases from the north of the SP (Shandong Peninsula)
shelf to the center of the NYS; whereas in the lower layers DIC increases from the north of the SP shelf to the center of
the NYS and South Yellow Sea. In the northeast of the NYS, DIC in all layers increases from the YR (Yalu River) estuary to
the centre of the NYS. The distribution of DIC in NYS can be used as an indicator of Yellow Sea Cold Water Mass (YSCWM). Air-sea
CO2 fluxes were calculated using three models and the results suggest that both the NYS and the QC waters are potential sources
of atmospheric CO2 in October.
Journal of Ocean University of China 05/2012; 8(4):366-376.
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ABSTRACT: A new kinetic spectrophotometric method is developed for the measurement of manganese (II) in water. The method is based on
the catalytic effect of manganese (II) with the oxidation of weak acid brilliant blue dye (RAWL) by KIO4 using the Nitrilo triacetic acid (NTA) as an activation reagent. The optimum conditions obtained are 40 mgL−1 RAWL, 1×10−4molL−1 KIO4, 2×10−4 molL−1 Nitrilo triacetic acid (NTA), pH = 5.8, the reaction time of 3.00 min and the temperature of 20.0 °C. Under the optimum conditions,
the proposed method allows the measurement of manganese (II) in a range of 0–50.0 ng mL−1 and with a detection limit of down to 0.158 ng mL−1. The recovery efficiency in measuring the standard manganese (II) solution is in a range of 98.5%–102%, and the RSD is in
a range of 0.76%–1.25%. The new method has been successfully applied to the measurement of manganese (II) in both fresh water
and seawater samples with satisfying results. Moreover, few cations and anions interfere with the measurement of manganese
(II). Compared with other kinetic catalytic methods and instrumental methods, the proposed method shows fairly good selectivity
and sensitivity, low cost, cheapness, low detection limit and rapidity. It can be applied on boats easily.
Journal of Ocean University of China 04/2012; 8(2):127-132.
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ABSTRACT: A new kinetic spectrophotometric method has been developed for the determination of vanadium (V). The method is based on the
catalytic effect of vanadium (V) on the oxidation of weak acid brilliant blue dye (RAWL) by KBrO3 using the citric acid as activation reagent. The obtained optimum conditions are: c (RAWL) = 1×10−4 molL−1, c (KBrO3) = 3×10−2 molL−1, c (citric acid) = 9×10−3 molL−1, pH = 2.50, the reaction time being 7.0 min and the temperature being 25.0°C. Under the optimum conditions, the proposed
method allows the determination of vanadium (V) in the range of 0–70.0 ng mL−1 and the detection limit is down to 0.407 ng mL−1. For standard vanadium (V) solution determination, the recovery efficiency is in the range of 98.5%–102% and the RSD ranges
from 0.76%–1.25%. Moreover, it is demonstrated that most cations and anions do not interfere with the determination of vanadium
(V) under the analytical condition. The new method was successfully applied in the determination of vanadium (V) in fresh
water and seawater samples with satisfactory results. Vanadium (V) in the seawater samples from Qingdao offshore was determined
using the method and the distribution of vanadium (V) was mapped. Compared with other instrumental analytical methods, the
proposed method shows good selectivity, sensitivity, simplicity, lower cost and rapidity. It can be employed on shipboard
easily.
Key wordsvanadium (V)-kinetic-spectrophotometry-catalytic effect-seawater
Journal of Ocean University of China 04/2012; 9(4):343-349.
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ABSTRACT: A new kinetic spectrophotometric method has been developed for the determination of trace Ni (II) in natural water. The method
is based on the catalytic effect of Ni (II) on the oxidation of weak acid brilliant blue dye (RAWL) by KIO4 in acid medium. The concentration of nickel (II) can be determined spectrophotometrically by measuring the decrease of absorbance
of RAWL at λ = 626 nm using the fix-time method. The influencing factors are investigated by the orthogonal experimental design. The obtained
optimum analytical conditions are: pH = 2.00, c
RAWL = 5.00×10−5 mol L−1, c
KIO
4 = 2.00×10−5 mol L −1, the reaction time t = 10 min and the temperature T = 25°C. Under the optimum conditions, the developed method allows the measurement of Ni (II) in a range of 0–40.0 ng mL−1. The standard deviation of eleven independent measurements of blank reaction is S = 3.08×10−3 and the limit of detection is 2.20 ng mL−1. The relative standard deviations (RSDs) in six replicate determinations of 5 ng mL−1 and 8 ng mL−1 Ni (II) are 2.87% and 1.11%, respectively. Moreover, the experiments show few cations and anions can interfere with the measurement
of Ni (II). The recovery efficiencies of this method are in a range of 97.0%–102.5% in freshwater samples. But there is a
decreasing effect, which is about 0.2 times the added Ni (II) in seawater medium. After reasonable calibration this processing
method is used for the determination of Ni (II) in seawater samples successfully. The results show this developed method has
high accuracy and precision, high sensitivity, large range of linearity and high speed. The method can, therefore, be employed
at room temperature.
Journal of Ocean University of China 04/2012; 9(1):25-30.
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ABSTRACT: A new analytical method using Back-Propagation (BP) artificial neural networks and spectrophotometry for simultaneous determination
of calcium and magnesium in tap water, the Yellow River water and seawater is established. By condition experiment, the optimum
analytical conditions for calcium, magnesium and Arsenazo (III) color reactions are obtained. Levenberg-Marquart (L-M) algorithm
is used for calculation in BP neural network. The topological structure of three-layer BP ANN network architecture is chosen
as 11-10-2 (nodes). The initial value of gradient coefficient μ is fixed at 0.001 and the increase factor and reduction factor
of μ take the default values of the system. The data are processed by computers with our own programs written in MATLAB 7.0.
The relative standard deviations of the calculated results for calcium and magnesium are 2.31% and 2.14%, respectively. The
results of standard addition method show that the recoveries of calcium and magnesium are 103.6% and 100.8% in the tap water,
103.2% and 96.6% in the Yellow River water (Lijin district of Shandong Province), and 98.8%–103.3% and 98.43%–103.4% in seawater
from Jiaozhou Bay of Qingdao. It is found that 14 common cations and anions do not interfere with the determination of calcium
and magnesium under the optimum experimental conditions. The comparative experiments do not show any obvious difference between
the results obtained by this new method and those obtained by the classical complexometric titration method in seawater medium.
This method exhibits good reproducibility and high accuracy in the determination of calcium and magnesium and can be used
for the simultaneous determination of Ca2+ and Mg2+ in tap water and natural water.
Key wordsartificial neural network-simultaneous determination-natural water-calcium-magnesium
Journal of Ocean University of China 04/2012; 9(3):229-234.
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ABSTRACT: A new kinetic spectrophotometric method has been developed for the determination of iron (III). The method is based on the
catalytic effect of iron (III) on the oxidation of weak acid brilliant blue dye (RAWL) by KIO4 in acid medium. The advantages of the proposed method are that it is sensitive, accurate, rapid, inexpensive, can be operated
under room temperature and has a large determination concentration range compared to other techniques. The obtained optimum
conditions are: pH 3.15, RAWL (200 mgL−1) 5.00 mL, Potassium periodate solution (0.01 molL−1) 0.30 mL, phenanthroline (0.02 molL−1) 1.00 mL, reaction temperature 25°C and reaction time 7 min. With this method iron could quantitively be determined in the
range 0.00–0.02 mgL−1, the detection limit being 4.10 × 10−10 g mL−1. The relative standard deviations (RSD) in five replicate determinations for 3 µgL−1 and 5 µgL−1 iron (III) are 3.1% and 1.9%, respectively. The method has been applied to the determination of iron (III) in tap water samples
and seawater samples (from the South China Sea), the recovery rates being 98.0% and 100.5%, respectively.
Journal of Ocean University of China 04/2008; 7(2):161-165.
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ABSTRACT: A new kinetic-spectrophotometric method is proposed for the determination of copper (II). The method is based on the catalytic
effect of copper (II) on the oxidation of weak acid brilliant blue dye (RAWL) by hydrogen peroxide. The copper (II) can be
determined spectrophotometrically by measuring the decrease of absorbance of RAWL at λ = 626 nm using the fix-time method.
The optimum reaction conditions are as follows: pH 7.20, buffer solution NaOH-KH2PO4, RAWL (200 mg L−1) 5.00 mL, H2O2 (30%) 0.50 mL, reaction temperature 80°C and reaction time 20 min. The linear range of this method is between 0 μgL−1 and 12 μgL−1 and the limit of detection is 0.011 μgL−1, the relative standard deviation (RSD) in five replicate determinations for 2 and 8 μgL−1 copper (II) are 3.2% and 2.3%, respectively. Twenty ions do not interfere in the determination of copper (II). The method
has been applied satisfactorily to the determination of copper (II) in freshwater samples (tap water and Yellow River water
from Lijin, Shandong, China) and seawater samples (from the South China Sea), the recovery rates are 98.0%, 102.5% and 96.0%,
respectively.
Journal of Ocean University of China 03/2007; 6(2):143-146.
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ABSTRACT: This paper investigates a microwave heating method for the determination of chemical oxygen demand (COD) in seawater. The
influences of microwave-power, heating time and standard substances on the results are studied. Using the proposed method,
we analyzed the glucose standard solution, the coefficient of variation being less than 2%. Compared with the traditional
electric stove heating method, the results of F-test and T-test showed that there was no significant difference between the
two methods, but the microwave method had slightly higher precision and reproducibility than the electric stove method. With
the microwave heating method, several seawater samples from Jiaozhou Bay and the South Yellow Sea were also analyzed. The
recovery was between 97.5% and 104.3%. This new method has the advantages of shortening the heating time, improving the working
efficiency and having simple operation and therefore can be used to analyze the COD in seawater.
Journal of Ocean University of China 03/2005; 4(2):152-156.
