結論

本實驗利用陽離子選擇性全注入結合掃略式線上濃縮法

（CSEI-sweeping-MEKC），針對古柯鹼及其代謝物進行線上濃縮的研 究，並且藉由固相萃取的前處理，成功地在尿液基質中看見古柯鹼及其 代謝物的訊號。此線上濃縮法最大特色是結合了兩種濃縮技術，首先以 場放大樣品電動注入陽離子分析物，利用分析物在不同電導度的溶液區 帶間會產生電場強度的差異，而造成堆積，達成第一步濃縮，然後再以 陰離子界面活性劑溶合分析物作第二步的掃掠式濃縮，最後再依MEKC 分離機制進行分離。

最佳條件為，背景緩衝溶液為pH 1.8、100 mM 磷酸含有 10%異丙 醇和10%四氫呋喃，高電導度緩衝溶液為 pH 1.8, 150 mM 磷酸，分析 物以去離子水稀釋，15kV 電壓注入 900 秒，分離用緩衝溶液 pH 1.8、

100 mM 磷酸含有 75 mM SDS 和 10%異丙醇和 10%四氫呋喃，施加-20 kV 分離電壓進行濃縮分離，偵測極限在 29.71 ~236.2 ppt 之間，古柯鹼 的放大倍率也有30,000 倍。在尿液樣品方面，藉由固相萃取的前處理 步驟可以清楚地在尿液基質中看到古柯鹼及其代謝物的訊號，回收率則 介於74.9~87.6% 之間。

50

O N O

COOCH

O N O

COOH

O NH O

COOCH

O N O

COOC

H

cocaine（CC） benzoylecgonine（BE）

norcocaine（NC） cocaethylene（CE）

Figure 4.1 The structures of cocaine and its metabolites.

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Figure 4.2 Effect of the percentage of THF on CSEI-sweeping-MEKC.

Condition, BGS: 100 mM phosphoric acid, pH 1.8; HCB: 150 mM phosphoric acid; SB: 100 mM phosphoric acid, 100 mM SDS; electrokinetic injection 15 kV, 900 sec; separation voltage: -20 kV. Analyte: CE 50 ppb; NC 50 ppb; CC 50 ppb;

BE 50 ppb.

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Figure 4.3 Effect of the concentration of SDS in separation buffer.

Condition, BGS: 100 mM phosphoric acid, 10% IPA&10% THF, pH 1.8；HCB:

150 mM phosphoric acid; SB: 100 mM phosphoric acid, 10% IPA&10% THF;

electrokinetic injection 15 kV, 900 sec; separation voltage: -20 kV. Analyte: CE 25 ppb; NC 25 ppb; CC 25 ppb; BE 50 ppb.

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Figure 4.4 Effect of hydrodynamic injection length of high conductivity buffer.

（A）90.65 mm;（B）181.3 mm;（C）362.6 mm;（D）543.9 mm.

Condition, BGS: 100 mM phosphoric acid, 10% IPA&10% THF, pH 1.8; HCB:

150 mM phosphoric acid; SB: 100 mM phosphoric acid, 10% IPA&10% THF, 75 mM SDS; electrokinetic injection 15 kV, 900 sec; separation voltage: -20 kV;

Analyte: peak 1, CE 10 ppb; peak 2, NC 10 ppb; peak 3, CC 10 ppb; peak 4, BE 50 ppb.

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Figure 4.5 Effect of electrokinetic injection time.

Condition, BGS: 100 mM phosphoric acid, 10% IPA&10% THF, pH 1.8; HCB:

150 mM phosphoric acid; SB: 100 mM phosphoric acid, 10% IPA&10% THF, 75 mM SDS; electrokinetic injection 15 kV; separation voltage: -20 kV. Analyte:

CE 10 ppb; NC 10 ppb; CC 10 ppb; BE 50 ppb.

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Figure 4.6 A comparison between CSEI-sweeping-MEKC, sweeping-MEKC and normal MEKC. (A) CSEI-sweeping-MEKC. Condition, BGS: 100 mM phosphoric acid, 10% IPA&10% THF, pH 1.8; HCB: 150 mM phosphoric acid;

SB: 100 mM phosphoric acid, 10% IPA&10% THF, 75 mM SDS; electrokinetic injection 15 kV, 900 sec; separation voltage: -20 kV. Analyte: peak 1, CE 10 ppb;

peak 2, NC 10 ppb; peak 3, CC 10 ppb; peak 4, BE 50 ppb. (B) Normal MEKC.

Sample concentration: 100 ppm; hydrodynamic inject: 0.5 psi, 3s. Separation condition: 100 mM phosphoric acid, 10% IPA&10% THF, 75 mM SDS;

separation voltage：-20 kV. (C) Sweeping-MEKC. Sample concentration: 5 ppm;

hydrodynamic inject: 0.5 psi, 120s. The separation condition was the same as normal MEKC.

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Figure 4.7 CSEI-sweeping-MEKC eletropherogram of extraction urine.

(A) blank urine, (B) sample urine. Analyte: peak 1, CE 10 ppb; peak 2, NC 10 ppb; peak 3, CC 10 ppb; peak 4, BE 50 ppb; *, unknown.

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Table 4.1 Stacking efficiency in term of peak height

Compound SEheighta SEheightb

cocaethylene 20,600 1,030

norcocaine 39,600 1,390

cocaine 30,000 1,740

benzoylecgonine 1,750 81

a peak height(CSEI-sweeping-MEKC)/ peak height(normal MEKC)×dilution factor

b peak height(CSEI-sweeping-MEKC)/ peak height(sweeping-MEKC)×dilution factor

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Table 4.2 Regression equation, Coefficient of variation (r²), limits of quantization (LOQ), limits of detection (LOD), and values of RSD for cocaine, benzoylecgonine, norcocaine, and cocaethylene during separation using sweeping-MEKC and CSEI-sweeping-MEKC technique, respectively.

a Calibration line (0.2 – 5 ppm): peak area (arbitrary units) = slope × concentration (ppm) + y-intercept

b Calibration line (0.2 – 10 ppb): peak area (arbitrary units) = slope × concentration (ppb) + y-intercept

c Calibration line (1 – 50 ppb): peak area (arbitrary units) = slope × concentration (ppb) + y-intercept

cocaethylene norcocaine cocaine benzoylecgonine sweeping-MEKC Regression equation Coefficient of variation LOD(S/N = 3, ppt; n = 3) LOQ(S/N = 10, ppt; n = 3) RSD(%; n = 3)

(a) Migration time (min) (b) Peak area

59 有會影響中樞神經系統的Δ⁹-tetrahydrocannabinol（Δ⁹-THC）成分。吸 食大麻會有陶醉感，Marijuana 是由葡萄牙文的 Mariguango 語彙演變而 來的，有令人陶醉的意思，在美國稱「Marijuana」者是泛指大麻植物的 tetrahydrocannabinol（THC-OH），其作用與 Δ⁹-THC 相似，最後會代謝