how to enum datatype using multiple values store?

hii i have column like datatype is enum and also store multiple value like comma seperated so is it possible to store ?

here is my code i try but i cant find any solution

here is my migrations

public function up()
	{
    	Schema::table('fraud_alerts', function (Blueprint $table) {
        		$table->enum('alert_for',['disposition','fraudalert'])->after('type')->nullable()->comment('Alert For');
    });
	}

here is my controller code

 public function store(Request $request){
	$requestData = $request->all();
	foreach($requestData['email'] as $i => $list){
		$data = array();
		$all = ['fraudalert','disposition'];
		$rowdata = array();
		if(in_array("all",$requestData['email_alert_for'])){
                    	$rowdata['alert_for'] = implode(',' , $all);
                	 }else{
               		$rowdata['alert_for'] = $requestData['email_alert_for'];
                	 }
		array_push($data,$rowdata);
                	FraudAlert::insert($data);
	}
}

i try but everytime store null value in alert_for column