To further remove the fat in the aqueous phase, we added different volumes of n-hexane to the aqueous phase extract of the standard sample and performed multiple extractions.
- Extract with 5ml n-hexane
Se-cyst
c = 19.421 µg/L
+/- 1.495 µg/L (7.70%)
-200n
-150n
-100n
-50.0n
-1.9e-005
0
-2.00e-5 0
2.00e-5
c (g/L)
4.00e-5
Add 5ml of n-hexane to the aqueous extract, shake for 5 minutes and let stand, wait for the layers to separate. Separate the n-hexane phase, collect the aqueous extract. Take 10ml of the aqueous extract and measure the DPCSV according to the optimal conditions given in Table 3.14. Proceed similarly and increase the number of extractions, the results are shown in Figures 3.56 to 3.64.
Se-cyst
c = 20.513 µg/L
+/- 0.246 µg/L (1.20%)
-150n
-100n
-50.0n
-2.1e-005
0
-2.00e-5
0
2.00e-5
c (g/L)
4.00e-5
I (A)
I (A)
Figure 3.56: DPCSV curve and standard addition graph to determine the form of selenium in the aqueous phase after removing fat with 5ml of n-hexane (1 time)
Figure 3.57: DPCSV curve and standard addition graph to determine the form of selenium in the aqueous phase after removing fat with 5ml of n-hexane (2 times)
Se-cyst
c = 20.486 µg/L
+/- 0.428 µg/L (2.09%)
-200n
-150n
-100n
-50.0n
-2e-005
0
-2.00e-5
0
2.00e-5
c (g/L)
4.00e-5
I (A)
Figure 3.58: DPCSV curve and standard addition graph to determine the form of selenium in the aqueous phase after removing fat with 5ml of n-hexane (3 times)
The research results showed that after 3 extractions with n-hexane, the concentration
Se-cyst
c = 20.212 µg/L
+/- 1.342 µg/L (6.64%)
Se(IV)
c = 0.126 µg/L
+/- 0.006 µg/L (4.75%)
-50.0n
-150n
-40.0n
-100n
-30.0n
-20.0n
-50.0n
-10.0n
-2e-005 -1.3e-007
0 0
-2.00e-5 0 2.00e-5 4.00e-5 -2.50e-7 0 2.50e-7 5.00e-7 7.50e-7 1.00e-6
c (g/L) c (g/L)
The Se-Cyst changed insignificantly, while the peak of Se(IV) was still not detected.
I ( A )
I ( A )
Figure 3.59: DPCSV curve and standard addition graph to determine the selenium form in the aqueous phase after defatting with 5ml n-hexane (4 times)
Figure 3.59 shows that the Se(IV) peak appeared next to the Se-Cyst peak, but the content found was very small (0.126 µg/l).
Se-cyst
c = 19.904 µg/L
+/- 0.306 µg/L (1.54%)
Se(IV)
c = 0.640 µg/L
+/- 0.013 µg/L (2.11%)
-200n
-150n
-150n
-125n
-100n
-100n
-75.0n
-50.0n
-50.0n
-2e-005
-6.4e- -25.0n
007
0
-2.00e-5 0
2.00e-5
c (g/L)
4.00e-5
0
-1.00e-6-5.00e-7 0 5.00e-71.00e-61.50e-62.00e-6
c (g/L)
I ( A )
I ( A )
Figure 3.60: DPCSV curve and standard addition graph to determine the form of selenium in the aqueous phase after removing fat with 5ml of n-hexane (5 times)
Figure 3.60 shows that the Se(IV) content found increased significantly (0.640
µg/l) compared with the case after 4 extractions.
Se-cyst
c = 21.617 µg/L
+/- 0.760 µg/L (3.51%)
-150n
-125n
I ( A )
-100n
-75.0n
-50.0n
-2.2e-005 -25.0n
0
-2.00e-5 0 2.00e-5 4.00e-5
c (g/L)
Se(IV)
c = 0.850 µg/L
+/- 0.079 µg/L (9.34%)
-100n
-80.0n
I ( A )
-60.0n
-40.0n
-20.0n
-8.5e-007
0
-1.00e-6 0 1.00e-6 2.00e-6 3.00e-6
c (g/L)
Figure 3.61: DPCSV curve and standard addition graph to determine the form of selenium in the aqueous phase after removing fat with 5ml of n-hexane (6 times)
Se-cyst
c = 20,800 µg/L
+/- 1.214 µg/L (5.84%)
Se(IV)
c = 0.901 µg/L
+/- 0.037 µg/L (4.15%)
-120n
-100n
-150n
-80.0n
-100n
-60.0n
-40.0n
-50.0n
-2.1e-005
0
-2.00e-5 0
2.00e-5
c (g/L)
4.00e-5
-20.0n
-9e-007
0
-1.00e-6 0 1.00e-6 2.00e-6
c (g/L)
I ( A )
I ( A )
Figure 3.62: DPCSV curve and standard addition graph to determine the form of selenium in the aqueous phase after removing fat with 5ml of n-hexane (7 times)
Figure 3.62 shows that the Se(IV) content found is close to the actual value in the standard sample (above 90%).
Se-cyst
c = 16.283 µg/L
+/- 0.002 µg/L (0.01%)
Se(IV)
c = 1.097 µg/L
+/- 0.011 µg/L (0.98%)
-200n
-120n
-100n
-150n
-80.0n
-100n
-60.0n
-40.0n
-50.0n
-1.6e-005
0
-2.00e-5
0 2.00e-5
c (g/L)
4.00e-5
-1.1e-006 -20.0n
0
-1.00e-6 0 1.00e-6 2.00e-6
c (g/L)
I ( A )
I ( A )
Figure 3.63: DPCSV curve and standard addition graph to determine the form of selenium in the aqueous phase after removing fat with 5ml of n-hexane (8 times)
Se-cyst
c = 15.270 µg/L
+/- 0.330 µg/L (2.16%)
-200n
Se(IV)
c = 1.012 µg/L
+/- 0.083 µg/L (8.20%)
-125n
-150n
-100n
-100n
-75.0n
-50.0n
-50.0n
-25.0n
-1.5e-005 -1e-006
0 0
-2.00e-5-1.00e-5 0 1.00e-52.00e-53.00e-54.00e-5 -1.00e-6 0 1.00e-6 2.00e-6
c (g/L) c (g/L)
I ( A )
I ( A )
Figure 3.64: DPCSV curve and standard addition graph to determine the form of selenium in the aqueous phase after removing fat with 5ml of n-hexane (9 times)
- Extract with 10ml n-hexane:
Add 10ml of n-hexane to the aqueous extract, shake for 5 minutes and let stand, wait for the layers to separate. Separate the n-hexane phase, collect the aqueous extract. Take 10ml of the aqueous extract and record the DPCSV according to the optimal conditions given in Table 3.14. Proceed similarly but increase the number of extractions, the results are shown in the figures from
Se-cyst
c = 20.238 µg/L
+/- 1.165 µg/L (5.76%)
-200n
-150n
-100n
-50.0n
-2e-005
0
-2.00e-5
0
2.00e-5
c (g/L)
4.00e-5
3.65 to 3.70.
I ( A )
Figure 3.65: DPCSV curve and standard addition graph to determine the form of selenium in the aqueous phase after removing fat with 10ml of n-hexane (1 time)
Se (IV)
c = 0.335 µg/L
+/- 0.017 µg/L (5.12 %)
-80.0n
-60.0n
)
A -40.0n
( I
-20.0n
-3.3e-007
0
-5.00e--27 .50e-7 0 2.50e-75.00e-77.50e-71.00e-6
c (g/L)
Se-cyst
c = 20.319 µg/L
+/- 0.108 µg/L (0.53%)
Se (IV)
c = 0.335 µg/L
+/- 0.017 µg/L (5.12 %)
-80.0n
-150n
-60.0n
-100n
-40.0n
-50.0n
-20.0n
-2e-005
-3.3e-007
0
-2.00e-5 0
2.00e-5
c (g/L)
4.00e-5
0
-5.00e--72.50e-7 0 2.50e-75.00e-77.50e-71.00e-6
c (g/L)
I ( A )
I ( A )
Figure 3.66: DPCSV curve and standard addition graph to determine the form of selenium in the aqueous phase after removing fat with 10ml of n-hexane (2 times)
In figure 3.66, the peak of Se(IV) appeared, but the content found was small (0.335µg/l).
Se-cyst
c = 20.941 µg/L
+/- 0.436 µg/L (2.08%)
-200n
Se(IV)
c = 1.155 µg/L
+/- 0.095 µg/L (8.22%)
-120n
-150n
-100n
-80.0n
-100n
-60.0n
-40.0n
-50.0n
-2.1e-005
-1.2e-006
-20.0n
0
0
-2.00e-5 0
2.00e-5
c (g/L)
4.00e-5
-1.00e-6
0
c (g/L)
1.00e-6 2.00e-6
I ( A )
I (A )
Figure 3.67: DPCSV curve and standard addition graph to determine the form of selenium in the aqueous phase after removing fat with 10ml of n-hexane (3 times)
Figure 3.67 shows that the content of Se-Cyst and Se(IV) found is over 100%.
Se-cyst
c = 19.606 µg/L
+/- 0.740 µg/L (3.77%)
-200n
-150n
I ( A )
-100n
-50.0n
-2e-005
0
-2.00e-5 0 2.00e-5 4.00e-5
c (g/L)
Se (IV)
Se (IV)
c = 1.103 µg/L
+/- 0.053 µg /L (4.81 %)
-150n
-125n
-100n
A -75.0n
)
( I
-50.0n
-1.1e-006 -25.0n
0
-1.00e-6 0 1.00e-6 2.00e-6
c (g/L)
c = 1.103 µg/L
+/- 0.053 µg /L (4.81 %)
-150n
-125n
-100n
I (A )
-75.0n
-50.0n
-1.1e-006 -25.0n
0
-1.00e-6 0 1.00e-6 2.00e-6
c (g/L)
Figure 3.68: DPCSV curve and standard addition graph to determine the form of selenium in the aqueous phase after removing fat with 10ml of n-hexane (4 times)
Se-cyst
c = 17.316 µg/L
+/- 0.625 µg/L (3.61%)
-200n
-150n
A -100n
)
( I
-50.0n
-1.7e-005
0
-2.00e-5 0 2.00e-5 4.00e-5
c (g/L)
Se-cyst
c = 17.316 µg/L
+/- 0.625 µg/L (3.61%)
-200n
Se(IV)
c = 1.014 µg/L
+/- 0.083 µg/L (8.19%)
-150n
-150n
-100n
-100n
-50.0n
-50.0n
-1.7e-005
0
-2.00e-5
-1e-006
0
-1.00e-6
0
2.00e-5
c (g/L)
4.00e-5
1.00e-6
c (g/L)
2.00e-6
0
I (A )
I (A)
Figure 3.69: DPCSV curve and standard addition graph to determine the form of selenium in the aqueous phase after removing fat with 10ml of n-hexane (5 times)
Se-cyst
c = 14.738 µg/L
+/- 0.272 µg/L (1.84%)
Se(IV)
c = 0.873 µg/L
+/- 0.025 µg/L (2.88%)
-250n
-150n
-200n
-125n
-150n
-100n
-75.0n
-100n
-50.0n
-50.0n
-1.5e-005
0
-2.00e-5-1.00e-5 0 1.00e-52.00e-53.00e-54.00e-5
c (g/L)
-8.7e- -25.0n
007
0
-1.00e-6 0
1.00e-6
c (g/L)
2.00e-6
I (A)
I (A)
Figure 3.70: DPCSV curve and standard addition graph to determine the form of selenium in the aqueous phase after removing fat with 10ml of n-hexane (6 times)
The summary of the results obtained is presented in Table 3.48.
Table 3.48: Research results on the influence of the number of extractions and the volume of n-hexane extraction solvent on the recovery of two forms of Se-Cyst and Se(IV)
Number of extractions
Selenium form | Extract with 5ml n-hexane | Extract with 10ml n-hexane | |||
Amount found (µg/l) | Recovery (%) | Amount found (µg/l) | Recovery (%) | ||
1 time | Se-Cyst | 19,421 | 97.11 | 20,238 | 101.19 |
Se(IV) | 0.000 | 0.00 | 0.000 | 0.00 | |
2 times | Se-Cyst | 20,513 | 102.57 | 20,319 | 101.60 |
Se(IV) | 0.000 | 0.00 | 0.335 | 33.50 | |
3 times | Se-Cyst | 20,486 | 102.43 | 20,941 | 104.71 |
Se(IV) | 0.000 | 0.00 | 1,155 | 115.50 | |
4 times | Se-Cyst | 20,212 | 101.06 | 19,606 | 98.03 |
Se(IV) | 0.126 | 12.60 | 1,103 | 110.30 | |
5 times | Se-Cyst | 19,904 | 99.52 | 17,316 | 86.58 |
Se(IV) | 0.640 | 64.00 | 1,014 | 101.40 | |
6 times | Se-Cyst | 21,671 | 108.36 | 14,738 | 73.69 |
Se(IV) | 0.850 | 85.00 | 0.873 | 87.30 | |
7 times | Se-Cyst | 20,800 | 104.00 | ||
Se(IV) | 0.901 | 90.10 | |||
8 times | Se-Cyst | 16,283 | 81.42 | ||
Se(IV) | 1,097 | 109.70 | |||
9 times | Se-Cyst | 15,270 | 76.35 | ||
Se(IV) | 1,012 | 101.20 | |||
Maybe you are interested!
-
Identify Rating Levels and Rating Scales
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of the islanders. Therefore, this indicator will be divided into two sub-indicators:
a1. Natural tourism attractiveness a2. Cultural tourism attractiveness
b. Tourist capacity
The two island communes in Quan Lan have different capacities to receive tourists. Minh Chau Commune is home to many standard hotels and resorts, attracting high-income domestic and international tourists. Meanwhile, Quan Lan Commune has many motels mainly built and operated by local people, so the scale and quality are not high, and will be suitable for ordinary tourists such as students.
c. Time of exploitation of Quan Lan Island Commune:
Quan Lan tourism is seasonal due to weather and climate conditions and festivals only take place on certain days of the year, specifically in spring. In Quan Lan commune, the period from April to June and from September to November is considered the best time to visit Quan Lan because the cultural tourism activities are mainly associated with festivals taking place during this time.
Minh Chau island commune:
Tourism exploitation time is all year round, because this is a place with a number of tourist attractions with diverse ecosystems such as Bai Tu Long National Park Research Center, Tram forest, Turtle Laying Beach, so besides coming to the beach for tourism and vacation in the summer, Minh Chau will attract research groups to come for tourism combined with research at other times of the year.
d. Sustainability
The sustainability of ecotourism sites in Quan Lan and Minh Chau communes depends on the sensitivity of the ecosystems to climate changes.
landscape. In general, these tourist destinations have a fairly high level of sustainability, because they are natural ecosystems, planned and protected. However, if a large number of tourists gather at certain times, it can exceed the carrying capacity and affect the sustainability of the environment (polluted beaches, damaged trees, animals moving away from their habitats, etc.), then the sustainability of the above ecosystems (natural ecosystems, human ecosystems) will also be affected and become less sustainable.
e. Location and accessibility
Both island communes have ports to take tourists to visit from Van Don wharf:
- Quan Lan – Van Don traffic route:
Phuc Thinh – Viet Anh high-speed boat and Quang Minh high-speed boat, depart at 8am and 2pm from Van Don to Quan Lan, and at 7am and 1pm from Quan Lan to Van Don. There are also wooden boats departing at 7am and 1pm.
- Van Don - Minh Chau traffic route:
Chung Huong high-speed train, Minh Chau train, morning 7:30 and afternoon 13:30 from Van Don to Minh Chau, morning 6:30 and afternoon 13:00 from Minh Chau to Van Don.
f. Infrastructure
Despite receiving investment attention, the issue of infrastructure and technical facilities for tourism on Quan Lan Island is still an issue that needs to be resolved because it has a direct impact on the implementation of ecotourism activities. The minimum conditions for serving tourists such as accommodation, electricity, water, communication, especially medical services, and security work need to be given top priority. Ecotourism spots in Minh Chau commune are assessed to have better infrastructure and technical facilities for tourism because there are quite complete and synchronous conditions for serving tourists, meeting many needs of domestic and foreign tourists.
3.2.1.4. Determine assessment levels and assessment scales
Corresponding to the levels of each criterion, the index is the score of those levels in the order of 4, 3, 2, 1 decreasing according to the standard of each level: very attractive (4), attractive (3), average (2), less attractive (1).
3.2.1.5. Determining the coefficients of the criteria
For the assessment of DLST in the two communes of Quan Lan and Minh Chau islands, the students added evaluation coefficients to show the importance of the criteria and indicators as follows:
Coefficient 3 with criteria: Attractiveness, Exploitation time. These are the 2 most important criteria for attracting tourists to tourism in general and eco-tourism in particular, so they have the highest coefficient.
Coefficient 2 with criteria: Capacity, Infrastructure, Location and accessibility . Because the assessment area is an island commune of Van Don district, the above criteria are selected by the author with appropriate coefficients at the average level.
Coefficient 1 with criteria: Sustainability. Quan Lan has natural and human-made ecotourism sites, with high biodiversity and little impact from local human factors. Most of the ecotourism sites are still wild, so they are highly sustainable.
3.2.1.6. Results of DLST assessment on Quan Lan island
a. Assessment of the potential for natural tourism development
For Minh Chau commune:
+ Natural tourism attractiveness is determined to be very attractive (4 points) and the most important coefficient (coefficient 3), so the score of the Attractiveness criterion is 4 x 3 = 12.
+ Capacity is determined as average (2 points) and the coefficient is quite important (coefficient 2), then the score of Capacity criterion is 2 x 2 = 4.
+ Exploitation time is long (4 points), the most important coefficient (coefficient 3) so the score of the Exploitation time criterion is 4 x 3 = 12.
+ Sustainability is determined as sustainable (4 points), the important coefficient is the average coefficient (coefficient 1), so the score of the Sustainability criterion is 4 x 1 = 4 points
+ Location and accessibility are determined to be quite favorable (2 points), the coefficient is quite important (coefficient 2), the criterion score is 2 x 2 = 4 points.
+ Infrastructure is assessed as good (3 points), the coefficient is quite important (coefficient 2), then the score of the Infrastructure criterion is 3 x 2 = 6 points.
The total score for evaluating DLST in Minh Chau commune according to 6 evaluation criteria is determined as: 12 + 4 + 12 + 4 + 4 + 6 = 42 points
Similar assessment for Quan Lan commune, we have the following table:
Table 3.3: Assessment of the potential for natural ecotourism development in Quan Lan and Minh Chau communes
Attractiveness of self-tourismof course
Capacity
Mining time
Sustainability
Location and accessibility
Infrastructure
Result
Point
DarkMulti
Point
DarkMulti
Point
DarkMulti
Point
DarkMulti
Point
DarkMulti
Point
DarkMulti
CommuneMinh Chau
12
12
4
8
12
12
4
4
4
8
6
8
42/52
Quan CommuneLan
6
12
6
8
9
12
4
4
4
8
4
8
33/52
b. Assessment of the potential for humanistic tourism development
For Quan Lan commune:
+ The attractiveness of human tourism is determined to be very attractive (4 points) and the most important coefficient (coefficient 3), so the score of the Attractiveness criterion is 4 x 3 = 12.
+ Capacity is determined to be large (3 points) and the coefficient is quite important (coefficient 2), then the score of the Capacity criterion is 3 x 2 = 6.
+ Mining time is average (3 points), the most important coefficient (coefficient 3) so the score of the Mining time criterion is 3 x 3 = 9.
+ Sustainability is determined as sustainable (4 points), the important coefficient is the average coefficient (coefficient 1), so the score of the Sustainability criterion is 4 x 1 = 4 points.
+ Location and accessibility are determined to be quite favorable (2 points), the coefficient is quite important (coefficient 2), the criterion score is 2 x 2 = 4 points.
+ Infrastructure is rated as average (2 points), the coefficient is quite important (coefficient 2), then the score of the Infrastructure criterion is 2 x 2 = 4 points.
The total score for evaluating DLST in Quan Lan commune according to 6 evaluation criteria is determined as: 12 + 6 + 6 + 4 + 4 + 4 = 36 points.
Similar assessment with Minh Chau commune we have the following table:
Table 3.4: Assessment of the potential for developing humanistic eco-tourism in Quan Lan and Minh Chau communes
Attractiveness of human tourismliterature
Capacity
Mining time
Sustainability
Location and accessibility
Infrastructure
Result
Point
DarkMulti
Point
DarkMulti
Point
DarkMulti
Point
DarkMulti
Point
DarkMulti
Point
DarkMulti
Quan CommuneLan
12
12
6
8
9
12
4
4
4
8
4
8
39/52
Minh CommuneChau
6
12
4
8
12
12
4
4
4
8
6
8
36/52
Basically, both Minh Chau and Quan Lan localities have quite favorable conditions for developing ecotourism. However, Quan Lan commune has more advantages to develop ecotourism in a humanistic direction, because this is an area with many famous historical relics such as Quan Lan Communal House, Quan Lan Pagoda, Temple worshiping the hero Tran Khanh Du, ... along with local festivals held annually such as the wind praying ceremony (March 15), Quan Lan festival (June 10-19); due to its location near the port and long exploitation time, the beaches in Quan Lan commune (especially Quan Lan beach) are no longer hygienic and clean to ensure the needs of tourists coming to relax and swim; this is also an area with many beautiful landscapes such as Got Beo wind pass, Ong Phong head, Voi Voi cave, but the ability to access these places is still very limited (dirt hill road, lots of gravel and rocks), especially during rainy and windy times; In addition, other natural resources such as mangrove forests and sea worms have not been really exploited for tourism purposes and ecotourism development. On the contrary, Minh Chau commune has more advantages in developing ecotourism in the direction of natural tourism, this is an area with diverse ecosystems such as at Rua De Beach, Bai Tu Long National Park Conservation Center...; Minh Chau beach is highly appreciated for its natural beauty and cleanliness, ranked in the top ten most beautiful beaches in Vietnam; Minh Chau commune is also home to Tram forest with a large area and a purity of up to 90%, suitable for building bridges through the forest (a very effective type of natural ecotourism currently applied by many countries) for tourists to sightsee, as well as for the purpose of studying and researching.
Figure 3.1: Thenmala Forest Bridge (India) Source: https://www.thenmalaecotourism.com/(August 21, 2019)
3.2.2. Using SWOT matrix to evaluate Quan Lan island tourism
General assessment of current tourism activities of Quan Lan island is shown through the following SWOT matrix:
Table 3.5: SWOT matrix evaluating tourism activities on Quan Lan island
Internal agent
Strengths- There is a lot of potential for tourism development, especially natural ecotourism and humanistic ecotourism.- The unskilled labor force is relatively abundant.- resource environmentunpolluted, still
Weaknesses- Poorly developed infrastructure, especially traffic routes to tourist destinations on the island.- The team of professional staff is still weak.- Tourism products in general
quite wild, originalintact
general and DLST in particularalone is monotonous.
External agents
Opportunity- Tourism is a key industry in the socio-economic development strategy of the province and Van Don economic zone.- Quan Lan was selected as a pilot area for eco-tourism development within the framework of the green growth project between Quang Ninh province and the Japanese organization JICA.- The flow of tourists and especially ecotourism in the world tends toincreasing
Challenge- Weather and climate change abnormally.- Competition in tourism products is increasingly fierce, especially with other localities in the province such as Ha Long, Mong Cai...- Awareness of tourists, especially domestic tourists, about ecotourism and nature conservation is not high.
Through summary analysis using SWOT matrix we see that:
To exploit strengths and take advantage of opportunities, it is necessary to:
- Diversify products and service types (build more tourism routes aimed at specific needs of tourists: experiential tourism immersed in nature, spiritual cultural tourism...)
- Effective exploitation of resources and differentiated products (natural resources and human resources)
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Standard Teaching Hour Norms of Lecturers at Khxhnv University - Hanoi National University According to Each Position -
Internship report at Vietnam Institute of Industrial Chemistry - 1 -
The Role of the Department of Education and Training in Mobilizing Resources to Build National Standard Primary Schools -
General Organic Chemistry - Hanoi University of Agriculture - 12
The research results show that if 5ml of n-hexane is used to extract fat, after 8 extractions, the Se-Cyst content decreases by 19%, while the Se(IV) content increases and remains stable after 9 extractions. If 10ml of n-hexane is used, the Se(IV) content decreases by 19%.